Add support for field aliases. (#32172)

* Add basic support for field aliases in index mappings. (#31287)
* Allow for aliases when fetching stored fields. (#31411)
* Add tests around accessing field aliases in scripts. (#31417)
* Add documentation around field aliases. (#31538)
* Add validation for field alias mappings. (#31518)
* Return both concrete fields and aliases in DocumentFieldMappers#getMapper. (#31671)
* Make sure that field-level security is enforced when using field aliases. (#31807)
* Add more comprehensive tests for field aliases in queries + aggregations. (#31565)
* Remove the deprecated method DocumentFieldMappers#getFieldMapper. (#32148)

docs/reference/indices/clearcache.asciidoc

@@ -16,7 +16,8 @@ explicitly by setting `query`, `fielddata` or `request`.
 
 All caches relating to a specific field(s) can also be cleared by
 specifying `fields` parameter with a comma delimited list of the
-relevant fields.
+relevant fields. Note that the provided names must refer to concrete
+fields -- objects and field aliases are not supported.
 
 [float]
 === Multi Index

docs/reference/mapping.asciidoc

@@ -124,8 +124,10 @@ fields to an existing index with the <<indices-put-mapping,PUT mapping API>>.
 
 Other than where documented, *existing field mappings cannot be
 updated*. Changing the mapping would mean invalidating already indexed
-documents.  Instead, you should create a new index with the correct mappings
-and <<docs-reindex,reindex>> your data into that index.
+documents. Instead, you should create a new index with the correct mappings
+and <<docs-reindex,reindex>> your data into that index. If you only wish
+to rename a field and not change its mappings, it may make sense to introduce
+an <<alias, `alias`>> field.
 
 [float]
 == Example mapping

docs/reference/mapping/types.asciidoc

@@ -40,6 +40,8 @@ string::        <<text,`text`>> and <<keyword,`keyword`>>
 
 <<parent-join>>::   Defines parent/child relation for documents within the same index
 
+<<alias>>::         Defines an alias to an existing field.
+
 <<feature>>::       Record numeric features to boost hits at query time.
 
 <<feature-vector>>:: Record numeric feature vectors to boost hits at query time.
@@ -58,6 +60,8 @@ the <<analysis-standard-analyzer,`standard` analyzer>>, the
 This is the purpose of _multi-fields_.  Most datatypes support multi-fields
 via the <<multi-fields>> parameter.
 
+include::types/alias.asciidoc[]
+
 include::types/array.asciidoc[]
 
 include::types/binary.asciidoc[]

docs/reference/mapping/types/alias.asciidoc

@@ -0,0 +1,101 @@
+[[alias]]
+=== Alias datatype
+
+An `alias` mapping defines an alternate name for a field in the  index.
+The alias can be used in place of the target field in <<search, search>> requests,
+and selected other APIs like <<search-field-caps, field capabilities>>.
+
+[source,js]
+--------------------------------
+PUT trips
+{
+  "mappings": {
+    "_doc": {
+      "properties": {
+        "distance": {
+          "type": "long"
+        },
+        "route_length_miles": {
+          "type": "alias",
+          "path": "distance" // <1>
+        },
+        "transit_mode": {
+          "type": "keyword"
+        }
+      }
+    }
+  }
+}
+
+GET _search
+{
+  "query": {
+    "range" : {
+      "route_length_miles" : {
+        "gte" : 39
+      }
+    }
+  }
+}
+--------------------------------
+// CONSOLE
+
+<1> The path to the target field. Note that this must be the full path, including any parent
+objects (e.g. `object1.object2.field`).
+
+Almost all components of the search request accept field aliases. In particular, aliases can be
+used in queries, aggregations, and sort fields, as well as when requesting `docvalue_fields`,
+`stored_fields`, suggestions, and highlights. Scripts also support aliases when accessing
+field values. Please see the section on <<unsupported-apis, unsupported APIs>> for exceptions.
+
+In some parts of the search request and when requesting field capabilities, field wildcard patterns can be
+provided. In these cases, the wildcard pattern will match field aliases in addition to concrete fields:
+
+[source,js]
+--------------------------------
+GET trips/_field_caps?fields=route_*,transit_mode
+--------------------------------
+// CONSOLE
+// TEST[continued]
+
+[[alias-targets]]
+==== Alias targets
+
+There are a few restrictions on the target of an alias:
+
+  * The target must be a concrete field, and not an object or another field alias.
+  * The target field must exist at the time the alias is created.
+  * If nested objects are defined, a field alias must have the same nested scope as its target.
+
+Additionally, a field alias can only have one target. This means that it is not possible to use a
+field alias to query over multiple target fields in a single clause.
+
+[[unsupported-apis]]
+==== Unsupported APIs
+
+Writes to field aliases are not supported: attempting to use an alias in an index or update request
+will result in a failure. Likewise, aliases cannot be used as the target of `copy_to`.
+
+Because alias names are not present in the document source, aliases cannot be used when performing
+source filtering. For example, the following request will return an empty result for `_source`:
+
+[source,js]
+--------------------------------
+GET /_search
+{
+  "query" : {
+    "match_all": {}
+  },
+  "_source": "route_length_miles"
+}
+--------------------------------
+// CONSOLE
+// TEST[continued]
+
+Currently only the search and field capabilities APIs will accept and resolve field aliases.
+Other APIs that accept field names, such as <<docs-termvectors, term vectors>>, cannot be used
+with field aliases.
+
+Finally, some queries, such as `terms`, `geo_shape`, and `more_like_this`, allow for fetching query
+information from an indexed document. Because field aliases aren't supported when fetching documents,
+the part of the query that specifies the lookup path cannot refer to a field by its alias.

modules/lang-expression/src/test/java/org/elasticsearch/script/expression/ExpressionTests.java

@@ -20,27 +20,52 @@
 package org.elasticsearch.script.expression;
 
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.index.IndexService;
-import org.elasticsearch.index.query.QueryShardContext;
+import org.elasticsearch.index.fielddata.AtomicNumericFieldData;
+import org.elasticsearch.index.fielddata.IndexNumericFieldData;
+import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
+import org.elasticsearch.index.mapper.MapperService;
+import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
+import org.elasticsearch.index.mapper.NumberFieldMapper.NumberType;
 import org.elasticsearch.script.ScriptException;
 import org.elasticsearch.script.SearchScript;
 import org.elasticsearch.search.lookup.SearchLookup;
-import org.elasticsearch.test.ESSingleNodeTestCase;
+import org.elasticsearch.test.ESTestCase;
 
+import java.io.IOException;
 import java.text.ParseException;
 import java.util.Collections;
 
-public class ExpressionTests extends ESSingleNodeTestCase {
-    ExpressionScriptEngine service;
-    SearchLookup lookup;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyObject;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class ExpressionTests extends ESTestCase {
+    private ExpressionScriptEngine service;
+    private SearchLookup lookup;
 
     @Override
     public void setUp() throws Exception {
         super.setUp();
-        IndexService index = createIndex("test", Settings.EMPTY, "type", "d", "type=double");
+
+        NumberFieldType fieldType = new NumberFieldType(NumberType.DOUBLE);
+        MapperService mapperService = mock(MapperService.class);
+        when(mapperService.fullName("field")).thenReturn(fieldType);
+        when(mapperService.fullName("alias")).thenReturn(fieldType);
+
+        SortedNumericDoubleValues doubleValues = mock(SortedNumericDoubleValues.class);
+        when(doubleValues.advanceExact(anyInt())).thenReturn(true);
+        when(doubleValues.nextValue()).thenReturn(2.718);
+
+        AtomicNumericFieldData atomicFieldData = mock(AtomicNumericFieldData.class);
+        when(atomicFieldData.getDoubleValues()).thenReturn(doubleValues);
+
+        IndexNumericFieldData fieldData = mock(IndexNumericFieldData.class);
+        when(fieldData.getFieldName()).thenReturn("field");
+        when(fieldData.load(anyObject())).thenReturn(atomicFieldData);
+
         service = new ExpressionScriptEngine(Settings.EMPTY);
-        QueryShardContext shardContext = index.newQueryShardContext(0, null, () -> 0, null);
-        lookup = new SearchLookup(index.mapperService(), shardContext::getForField, null);
+        lookup = new SearchLookup(mapperService, ignored -> fieldData, null);
     }
 
     private SearchScript.LeafFactory compile(String expression) {
@@ -50,22 +75,38 @@ public class ExpressionTests extends ESSingleNodeTestCase {
 
     public void testNeedsScores() {
         assertFalse(compile("1.2").needs_score());
-        assertFalse(compile("doc['d'].value").needs_score());
+        assertFalse(compile("doc['field'].value").needs_score());
         assertTrue(compile("1/_score").needs_score());
-        assertTrue(compile("doc['d'].value * _score").needs_score());
+        assertTrue(compile("doc['field'].value * _score").needs_score());
     }
 
     public void testCompileError() {
         ScriptException e = expectThrows(ScriptException.class, () -> {
-            compile("doc['d'].value * *@#)(@$*@#$ + 4");
+            compile("doc['field'].value * *@#)(@$*@#$ + 4");
         });
         assertTrue(e.getCause() instanceof ParseException);
     }
 
     public void testLinkError() {
         ScriptException e = expectThrows(ScriptException.class, () -> {
-            compile("doc['e'].value * 5");
+            compile("doc['nonexistent'].value * 5");
         });
         assertTrue(e.getCause() instanceof ParseException);
     }
+
+    public void testFieldAccess() throws IOException {
+        SearchScript script = compile("doc['field'].value").newInstance(null);
+        script.setDocument(1);
+
+        double result = script.runAsDouble();
+        assertEquals(2.718, result, 0.0);
+    }
+
+    public void testFieldAccessWithFieldAlias() throws IOException {
+        SearchScript script = compile("doc['alias'].value").newInstance(null);
+        script.setDocument(1);
+
+        double result = script.runAsDouble();
+        assertEquals(2.718, result, 0.0);
+    }
 }

modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQuery.java

@@ -194,6 +194,10 @@ final class PercolateQuery extends Query implements Accountable {
         return candidateMatchesQuery;
     }
 
+    Query getVerifiedMatchesQuery() {
+        return verifiedMatchesQuery;
+    }
+
     // Comparing identity here to avoid being cached
     // Note that in theory if the same instance gets used multiple times it could still get cached,
     // however since we create a new query instance each time we this query this shouldn't happen and thus

modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQueryBuilder.java

@@ -618,13 +618,13 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
             docSearcher.setQueryCache(null);
         }
 
-        PercolatorFieldMapper percolatorFieldMapper = (PercolatorFieldMapper) docMapper.mappers().getMapper(field);
-        boolean mapUnmappedFieldsAsString = percolatorFieldMapper.isMapUnmappedFieldAsText();
-        QueryShardContext percolateShardContext = wrap(context);
-
-        String name = this.name != null ? this.name : field;
         PercolatorFieldMapper.FieldType pft = (PercolatorFieldMapper.FieldType) fieldType;
-        PercolateQuery.QueryStore queryStore = createStore(pft.queryBuilderField, percolateShardContext, mapUnmappedFieldsAsString);
+        String name = this.name != null ? this.name : pft.name();
+        QueryShardContext percolateShardContext = wrap(context);
+        PercolateQuery.QueryStore queryStore = createStore(pft.queryBuilderField,
+            percolateShardContext,
+            pft.mapUnmappedFieldsAsText);
+
         return pft.percolateQuery(name, queryStore, documents, docSearcher, context.indexVersionCreated());
     }
 

modules/percolator/src/main/java/org/elasticsearch/percolator/PercolatorFieldMapper.java

@@ -136,6 +136,8 @@ public class PercolatorFieldMapper extends FieldMapper {
             fieldType.rangeField = rangeFieldMapper.fieldType();
             NumberFieldMapper minimumShouldMatchFieldMapper = createMinimumShouldMatchField(context);
             fieldType.minimumShouldMatchField = minimumShouldMatchFieldMapper.fieldType();
+            fieldType.mapUnmappedFieldsAsText = getMapUnmappedFieldAsText(context.indexSettings());
+
             context.path().remove();
             setupFieldType(context);
             return new PercolatorFieldMapper(name(), fieldType, defaultFieldType, context.indexSettings(),
@@ -143,6 +145,10 @@ public class PercolatorFieldMapper extends FieldMapper {
                     extractionResultField, queryBuilderField, rangeFieldMapper, minimumShouldMatchFieldMapper);
         }
 
+        private static boolean getMapUnmappedFieldAsText(Settings indexSettings) {
+            return INDEX_MAP_UNMAPPED_FIELDS_AS_TEXT_SETTING.get(indexSettings);
+        }
+
         static KeywordFieldMapper createExtractQueryFieldBuilder(String name, BuilderContext context) {
             KeywordFieldMapper.Builder queryMetaDataFieldBuilder = new KeywordFieldMapper.Builder(name);
             queryMetaDataFieldBuilder.docValues(false);
@@ -195,6 +201,7 @@ public class PercolatorFieldMapper extends FieldMapper {
         MappedFieldType minimumShouldMatchField;
 
         RangeFieldMapper.RangeFieldType rangeField;
+        boolean mapUnmappedFieldsAsText;
 
         FieldType() {
             setIndexOptions(IndexOptions.NONE);
@@ -209,6 +216,7 @@ public class PercolatorFieldMapper extends FieldMapper {
             queryBuilderField = ref.queryBuilderField;
             rangeField = ref.rangeField;
             minimumShouldMatchField = ref.minimumShouldMatchField;
+            mapUnmappedFieldsAsText = ref.mapUnmappedFieldsAsText;
         }
 
         @Override
@@ -327,7 +335,6 @@ public class PercolatorFieldMapper extends FieldMapper {
 
     }
 
-    private final boolean mapUnmappedFieldAsText;
     private final Supplier<QueryShardContext> queryShardContext;
     private KeywordFieldMapper queryTermsField;
     private KeywordFieldMapper extractionResultField;
@@ -348,14 +355,9 @@ public class PercolatorFieldMapper extends FieldMapper {
         this.extractionResultField = extractionResultField;
         this.queryBuilderField = queryBuilderField;
         this.minimumShouldMatchFieldMapper = minimumShouldMatchFieldMapper;
-        this.mapUnmappedFieldAsText = getMapUnmappedFieldAsText(indexSettings);
         this.rangeFieldMapper = rangeFieldMapper;
     }
 
-    private static boolean getMapUnmappedFieldAsText(Settings indexSettings) {
-        return INDEX_MAP_UNMAPPED_FIELDS_AS_TEXT_SETTING.get(indexSettings);
-    }
-
     @Override
     public FieldMapper updateFieldType(Map<String, MappedFieldType> fullNameToFieldType) {
         PercolatorFieldMapper updated = (PercolatorFieldMapper) super.updateFieldType(fullNameToFieldType);
@@ -402,7 +404,7 @@ public class PercolatorFieldMapper extends FieldMapper {
 
         Version indexVersion = context.mapperService().getIndexSettings().getIndexVersionCreated();
         createQueryBuilderField(indexVersion, queryBuilderField, queryBuilder, context);
-        Query query = toQuery(queryShardContext, mapUnmappedFieldAsText, queryBuilder);
+        Query query = toQuery(queryShardContext, isMapUnmappedFieldAsText(), queryBuilder);
         processQuery(query, context);
         return null;
     }
@@ -522,7 +524,7 @@ public class PercolatorFieldMapper extends FieldMapper {
     }
 
     boolean isMapUnmappedFieldAsText() {
-        return mapUnmappedFieldAsText;
+        return ((FieldType) fieldType).mapUnmappedFieldsAsText;
     }
 
     /**

modules/percolator/src/test/java/org/elasticsearch/percolator/CandidateQueryTests.java

@@ -194,8 +194,7 @@ public class CandidateQueryTests extends ESSingleNodeTestCase {
         }
         Collections.sort(intValues);
 
-        MappedFieldType intFieldType = mapperService.documentMapper("type").mappers()
-            .getMapper("int_field").fieldType();
+        MappedFieldType intFieldType = mapperService.fullName("int_field");
 
         List<Supplier<Query>> queryFunctions = new ArrayList<>();
         queryFunctions.add(MatchNoDocsQuery::new);
@@ -327,8 +326,7 @@ public class CandidateQueryTests extends ESSingleNodeTestCase {
         stringValues.add("value2");
         stringValues.add("value3");
 
-        MappedFieldType intFieldType = mapperService.documentMapper("type").mappers()
-            .getMapper("int_field").fieldType();
+        MappedFieldType intFieldType = mapperService.fullName("int_field");
         List<int[]> ranges = new ArrayList<>();
         ranges.add(new int[]{-5, 5});
         ranges.add(new int[]{0, 10});

modules/percolator/src/test/java/org/elasticsearch/percolator/PercolateQueryBuilderTests.java

@@ -75,7 +75,8 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
         PercolateQueryBuilder.DOCUMENTS_FIELD.getPreferredName()
     };
 
-    private static String queryField;
+    private static String queryField = "field";
+    private static String aliasField = "alias";
     private static String docType;
 
     private String indexedDocumentIndex;
@@ -96,9 +97,11 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
     @Override
     protected void initializeAdditionalMappings(MapperService mapperService) throws IOException {
         queryField = randomAlphaOfLength(4);
+        aliasField = randomAlphaOfLength(4);
+
         String docType = "_doc";
         mapperService.merge(docType, new CompressedXContent(Strings.toString(PutMappingRequest.buildFromSimplifiedDef(docType,
-                queryField, "type=percolator"
+                queryField, "type=percolator", aliasField, "type=alias,path=" + queryField
         ))), MapperService.MergeReason.MAPPING_UPDATE);
         mapperService.merge(docType, new CompressedXContent(Strings.toString(PutMappingRequest.buildFromSimplifiedDef(docType,
                 STRING_FIELD_NAME, "type=text"
@@ -355,4 +358,21 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
         builder = rewriteAndFetch(builder, createShardContext());
         builder.writeTo(new BytesStreamOutput(10));
     }
+
+    public void testFieldAlias() throws IOException {
+        QueryShardContext shardContext = createShardContext();
+
+        PercolateQueryBuilder builder = doCreateTestQueryBuilder(false);
+        QueryBuilder rewrittenBuilder = rewriteAndFetch(builder, shardContext);
+        PercolateQuery query = (PercolateQuery) rewrittenBuilder.toQuery(shardContext);
+
+        PercolateQueryBuilder aliasBuilder = new PercolateQueryBuilder(aliasField,
+            builder.getDocuments(),
+            builder.getXContentType());
+        QueryBuilder rewrittenAliasBuilder = rewriteAndFetch(aliasBuilder, shardContext);
+        PercolateQuery aliasQuery = (PercolateQuery) rewrittenAliasBuilder.toQuery(shardContext);
+
+        assertEquals(query.getCandidateMatchesQuery(), aliasQuery.getCandidateMatchesQuery());
+        assertEquals(query.getVerifiedMatchesQuery(), aliasQuery.getVerifiedMatchesQuery());
+    }
 }

modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorFieldMapperTests.java

@@ -224,10 +224,10 @@ public class PercolatorFieldMapperTests extends ESSingleNodeTestCase {
     public void testExtractRanges() throws Exception {
         addQueryFieldMappings();
         BooleanQuery.Builder bq = new BooleanQuery.Builder();
-        Query rangeQuery1 = mapperService.documentMapper("doc").mappers().getMapper("number_field1").fieldType()
+        Query rangeQuery1 = mapperService.fullName("number_field1")
             .rangeQuery(10, 20, true, true, null, null, null, null);
         bq.add(rangeQuery1, Occur.MUST);
-        Query rangeQuery2 = mapperService.documentMapper("doc").mappers().getMapper("number_field1").fieldType()
+        Query rangeQuery2 = mapperService.fullName("number_field1")
             .rangeQuery(15, 20, true, true, null, null, null, null);
         bq.add(rangeQuery2, Occur.MUST);
 
@@ -255,7 +255,7 @@ public class PercolatorFieldMapperTests extends ESSingleNodeTestCase {
         // Range queries on different fields:
         bq = new BooleanQuery.Builder();
         bq.add(rangeQuery1, Occur.MUST);
-        rangeQuery2 = mapperService.documentMapper("doc").mappers().getMapper("number_field2").fieldType()
+        rangeQuery2 = mapperService.fullName("number_field2")
             .rangeQuery(15, 20, true, true, null, null, null, null);
         bq.add(rangeQuery2, Occur.MUST);
 

server/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java

@@ -39,7 +39,7 @@ import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.mapper.DocumentFieldMappers;
 import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.indices.TypeMissingException;
@@ -174,19 +174,19 @@ public class TransportGetFieldMappingsIndexAction extends TransportSingleShardAc
         final DocumentFieldMappers allFieldMappers = documentMapper.mappers();
         for (String field : request.fields()) {
             if (Regex.isMatchAllPattern(field)) {
-                for (FieldMapper fieldMapper : allFieldMappers) {
-                    addFieldMapper(fieldPredicate, fieldMapper.fieldType().name(), fieldMapper, fieldMappings, request.includeDefaults());
+                for (Mapper fieldMapper : allFieldMappers) {
+                    addFieldMapper(fieldPredicate, fieldMapper.name(), fieldMapper, fieldMappings, request.includeDefaults());
                 }
             } else if (Regex.isSimpleMatchPattern(field)) {
-                for (FieldMapper fieldMapper : allFieldMappers) {
-                    if (Regex.simpleMatch(field, fieldMapper.fieldType().name())) {
-                        addFieldMapper(fieldPredicate,  fieldMapper.fieldType().name(),
+                for (Mapper fieldMapper : allFieldMappers) {
+                    if (Regex.simpleMatch(field, fieldMapper.name())) {
+                        addFieldMapper(fieldPredicate,  fieldMapper.name(),
                                 fieldMapper, fieldMappings, request.includeDefaults());
                     }
                 }
             } else {
                 // not a pattern
-                FieldMapper fieldMapper = allFieldMappers.getMapper(field);
+                Mapper fieldMapper = allFieldMappers.getMapper(field);
                 if (fieldMapper != null) {
                     addFieldMapper(fieldPredicate, field, fieldMapper, fieldMappings, request.includeDefaults());
                 } else if (request.probablySingleFieldRequest()) {
@@ -198,7 +198,7 @@ public class TransportGetFieldMappingsIndexAction extends TransportSingleShardAc
     }
 
     private static void addFieldMapper(Predicate<String> fieldPredicate,
-                                       String field, FieldMapper fieldMapper, Map<String, FieldMappingMetaData> fieldMappings,
+                                       String field, Mapper fieldMapper, Map<String, FieldMappingMetaData> fieldMappings,
                                        boolean includeDefaults) {
         if (fieldMappings.containsKey(field)) {
             return;
@@ -207,7 +207,7 @@ public class TransportGetFieldMappingsIndexAction extends TransportSingleShardAc
             try {
                 BytesReference bytes = XContentHelper.toXContent(fieldMapper, XContentType.JSON,
                         includeDefaults ? includeDefaultsParams : ToXContent.EMPTY_PARAMS, false);
-                fieldMappings.put(field, new FieldMappingMetaData(fieldMapper.fieldType().name(), bytes));
+                fieldMappings.put(field, new FieldMappingMetaData(fieldMapper.name(), bytes));
             } catch (IOException e) {
                 throw new ElasticsearchException("failed to serialize XContent of field [" + field + "]", e);
             }

server/src/main/java/org/elasticsearch/action/fieldcaps/TransportFieldCapabilitiesIndexAction.java

@@ -83,8 +83,8 @@ public class TransportFieldCapabilitiesIndexAction extends TransportSingleShardA
         for (String field : fieldNames) {
             MappedFieldType ft = mapperService.fullName(field);
             if (ft != null) {
-                FieldCapabilities fieldCap = new FieldCapabilities(field, ft.typeName(), ft.isSearchable(), ft.isAggregatable());
-                if (indicesService.isMetaDataField(field) || fieldPredicate.test(field)) {
+                if (indicesService.isMetaDataField(field) || fieldPredicate.test(ft.name())) {
+                    FieldCapabilities fieldCap = new FieldCapabilities(field, ft.typeName(), ft.isSearchable(), ft.isAggregatable());
                     responseMap.put(field, fieldCap);
                 }
             }

server/src/main/java/org/elasticsearch/index/IndexWarmer.java

@@ -27,8 +27,6 @@ import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexFieldDataService;
-import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.FieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.shard.IndexShard;
@@ -121,16 +119,12 @@ public final class IndexWarmer extends AbstractComponent {
         public TerminationHandle warmReader(final IndexShard indexShard, final Engine.Searcher searcher) {
             final MapperService mapperService = indexShard.mapperService();
             final Map<String, MappedFieldType> warmUpGlobalOrdinals = new HashMap<>();
-            DocumentMapper docMapper = mapperService.documentMapper();
-            if (docMapper != null) {
-                for (FieldMapper fieldMapper : docMapper.mappers()) {
-                    final MappedFieldType fieldType = fieldMapper.fieldType();
-                    final String indexName = fieldType.name();
-                    if (fieldType.eagerGlobalOrdinals() == false) {
-                        continue;
-                    }
-                    warmUpGlobalOrdinals.put(indexName, fieldType);
+            for (MappedFieldType fieldType : mapperService.fieldTypes()) {
+                final String indexName = fieldType.name();
+                if (fieldType.eagerGlobalOrdinals() == false) {
+                    continue;
                 }
+                warmUpGlobalOrdinals.put(indexName, fieldType);
             }
             final CountDownLatch latch = new CountDownLatch(warmUpGlobalOrdinals.size());
             for (final MappedFieldType fieldType : warmUpGlobalOrdinals.values()) {

server/src/main/java/org/elasticsearch/index/fieldvisitor/CustomFieldsVisitor.java

@@ -19,11 +19,8 @@
 package org.elasticsearch.index.fieldvisitor;
 
 import org.apache.lucene.index.FieldInfo;
-import org.elasticsearch.common.regex.Regex;
 
 import java.io.IOException;
-import java.util.Collections;
-import java.util.List;
 import java.util.Set;
 
 /**
@@ -35,16 +32,10 @@ import java.util.Set;
 public class CustomFieldsVisitor extends FieldsVisitor {
 
     private final Set<String> fields;
-    private final List<String> patterns;
-
-    public CustomFieldsVisitor(Set<String> fields, List<String> patterns, boolean loadSource) {
-        super(loadSource);
-        this.fields = fields;
-        this.patterns = patterns;
-    }
 
     public CustomFieldsVisitor(Set<String> fields, boolean loadSource) {
-        this(fields, Collections.emptyList(), loadSource);
+        super(loadSource);
+        this.fields = fields;
     }
 
     @Override
@@ -55,11 +46,6 @@ public class CustomFieldsVisitor extends FieldsVisitor {
         if (fields.contains(fieldInfo.name)) {
             return Status.YES;
         }
-        for (String pattern : patterns) {
-            if (Regex.simpleMatch(pattern, fieldInfo.name)) {
-                return Status.YES;
-            }
-        }
         return Status.NO;
     }
 }

server/src/main/java/org/elasticsearch/index/get/ShardGetService.java

@@ -39,7 +39,7 @@ import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.fieldvisitor.CustomFieldsVisitor;
 import org.elasticsearch.index.fieldvisitor.FieldsVisitor;
 import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.RoutingFieldMapper;
 import org.elasticsearch.index.mapper.SourceFieldMapper;
@@ -202,7 +202,7 @@ public final class ShardGetService extends AbstractIndexShardComponent {
 
         if (gFields != null && gFields.length > 0) {
             for (String field : gFields) {
-                FieldMapper fieldMapper = docMapper.mappers().getMapper(field);
+                Mapper fieldMapper = docMapper.mappers().getMapper(field);
                 if (fieldMapper == null) {
                     if (docMapper.objectMappers().get(field) != null) {
                         // Only fail if we know it is a object field, missing paths / fields shouldn't fail.

server/src/main/java/org/elasticsearch/index/mapper/DocumentFieldMappers.java

@@ -28,10 +28,10 @@ import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 
-public final class DocumentFieldMappers implements Iterable<FieldMapper> {
+public final class DocumentFieldMappers implements Iterable<Mapper> {
 
     /** Full field name to mapper */
-    private final Map<String, FieldMapper> fieldMappers;
+    private final Map<String, Mapper> fieldMappers;
 
     private final FieldNameAnalyzer indexAnalyzer;
     private final FieldNameAnalyzer searchAnalyzer;
@@ -44,8 +44,12 @@ public final class DocumentFieldMappers implements Iterable<FieldMapper> {
         analyzers.put(key, value);
     }
 
-    public DocumentFieldMappers(Collection<FieldMapper> mappers, Analyzer defaultIndex, Analyzer defaultSearch, Analyzer defaultSearchQuote) {
-        Map<String, FieldMapper> fieldMappers = new HashMap<>();
+    public DocumentFieldMappers(Collection<FieldMapper> mappers,
+                                Collection<FieldAliasMapper> aliasMappers,
+                                Analyzer defaultIndex,
+                                Analyzer defaultSearch,
+                                Analyzer defaultSearchQuote) {
+        Map<String, Mapper> fieldMappers = new HashMap<>();
         Map<String, Analyzer> indexAnalyzers = new HashMap<>();
         Map<String, Analyzer> searchAnalyzers = new HashMap<>();
         Map<String, Analyzer> searchQuoteAnalyzers = new HashMap<>();
@@ -56,14 +60,24 @@ public final class DocumentFieldMappers implements Iterable<FieldMapper> {
             put(searchAnalyzers, fieldType.name(), fieldType.searchAnalyzer(), defaultSearch);
             put(searchQuoteAnalyzers, fieldType.name(), fieldType.searchQuoteAnalyzer(), defaultSearchQuote);
         }
+
+        for (FieldAliasMapper aliasMapper : aliasMappers) {
+            fieldMappers.put(aliasMapper.name(), aliasMapper);
+        }
+
         this.fieldMappers = Collections.unmodifiableMap(fieldMappers);
         this.indexAnalyzer = new FieldNameAnalyzer(indexAnalyzers);
         this.searchAnalyzer = new FieldNameAnalyzer(searchAnalyzers);
         this.searchQuoteAnalyzer = new FieldNameAnalyzer(searchQuoteAnalyzers);
     }
 
-    /** Returns the mapper for the given field */
-    public FieldMapper getMapper(String field) {
+    /**
+     * Returns the leaf mapper associated with this field name. Note that the returned mapper
+     * could be either a concrete {@link FieldMapper}, or a {@link FieldAliasMapper}.
+     *
+     * To access a field's type information, {@link MapperService#fullName} should be used instead.
+     */
+    public Mapper getMapper(String field) {
         return fieldMappers.get(field);
     }
 
@@ -87,7 +101,7 @@ public final class DocumentFieldMappers implements Iterable<FieldMapper> {
         return this.searchQuoteAnalyzer;
     }
 
-    public Iterator<FieldMapper> iterator() {
+    public Iterator<Mapper> iterator() {
         return fieldMappers.values().iterator();
     }
 }

server/src/main/java/org/elasticsearch/index/mapper/DocumentMapper.java

@@ -133,15 +133,18 @@ public class DocumentMapper implements ToXContentFragment {
         // collect all the mappers for this type
         List<ObjectMapper> newObjectMappers = new ArrayList<>();
         List<FieldMapper> newFieldMappers = new ArrayList<>();
+        List<FieldAliasMapper> newFieldAliasMappers = new ArrayList<>();
         for (MetadataFieldMapper metadataMapper : this.mapping.metadataMappers) {
             if (metadataMapper instanceof FieldMapper) {
                 newFieldMappers.add(metadataMapper);
             }
         }
-        MapperUtils.collect(this.mapping.root, newObjectMappers, newFieldMappers);
+        MapperUtils.collect(this.mapping.root,
+            newObjectMappers, newFieldMappers, newFieldAliasMappers);
 
         final IndexAnalyzers indexAnalyzers = mapperService.getIndexAnalyzers();
         this.fieldMappers = new DocumentFieldMappers(newFieldMappers,
+                newFieldAliasMappers,
                 indexAnalyzers.getDefaultIndexAnalyzer(),
                 indexAnalyzers.getDefaultSearchAnalyzer(),
                 indexAnalyzers.getDefaultSearchQuoteAnalyzer());

server/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java

@@ -459,13 +459,18 @@ final class DocumentParser {
     private static void parseObjectOrField(ParseContext context, Mapper mapper) throws IOException {
         if (mapper instanceof ObjectMapper) {
             parseObjectOrNested(context, (ObjectMapper) mapper);
-        } else {
-            FieldMapper fieldMapper = (FieldMapper)mapper;
+        } else if (mapper instanceof FieldMapper) {
+            FieldMapper fieldMapper = (FieldMapper) mapper;
             Mapper update = fieldMapper.parse(context);
             if (update != null) {
                 context.addDynamicMapper(update);
             }
             parseCopyFields(context, fieldMapper.copyTo().copyToFields());
+        } else if (mapper instanceof FieldAliasMapper) {
+            throw new IllegalArgumentException("Cannot write to a field alias [" + mapper.name() + "].");
+        } else {
+            throw new IllegalStateException("The provided mapper [" + mapper.name() + "] has an unrecognized type [" +
+                mapper.getClass().getSimpleName() + "].");
         }
     }
 
@@ -827,9 +832,16 @@ final class DocumentParser {
 
     /** Creates an copy of the current field with given field name and boost */
     private static void parseCopy(String field, ParseContext context) throws IOException {
-        FieldMapper fieldMapper = context.docMapper().mappers().getMapper(field);
-        if (fieldMapper != null) {
-            fieldMapper.parse(context);
+        Mapper mapper = context.docMapper().mappers().getMapper(field);
+        if (mapper != null) {
+            if (mapper instanceof FieldMapper) {
+                ((FieldMapper) mapper).parse(context);
+            } else if (mapper instanceof FieldAliasMapper) {
+                throw new IllegalArgumentException("Cannot copy to a field alias [" + mapper.name() + "].");
+            } else {
+                throw new IllegalStateException("The provided mapper [" + mapper.name() +
+                    "] has an unrecognized type [" + mapper.getClass().getSimpleName() + "].");
+            }
         } else {
             // The path of the dest field might be completely different from the current one so we need to reset it
             context = context.overridePath(new ContentPath(0));
@@ -837,8 +849,8 @@ final class DocumentParser {
             final String[] paths = splitAndValidatePath(field);
             final String fieldName = paths[paths.length-1];
             Tuple<Integer, ObjectMapper> parentMapperTuple = getDynamicParentMapper(context, paths, null);
-            ObjectMapper mapper = parentMapperTuple.v2();
-            parseDynamicValue(context, mapper, fieldName, context.parser().currentToken());
+            ObjectMapper objectMapper = parentMapperTuple.v2();
+            parseDynamicValue(context, objectMapper, fieldName, context.parser().currentToken());
             for (int i = 0; i < parentMapperTuple.v1(); i++) {
                 context.path().remove();
             }
@@ -849,46 +861,46 @@ final class DocumentParser {
             ObjectMapper currentParent) {
         ObjectMapper mapper = currentParent == null ? context.root() : currentParent;
         int pathsAdded = 0;
-            ObjectMapper parent = mapper;
-            for (int i = 0; i < paths.length-1; i++) {
-            String currentPath = context.path().pathAsText(paths[i]);
-            FieldMapper existingFieldMapper = context.docMapper().mappers().getMapper(currentPath);
-            if (existingFieldMapper != null) {
-                throw new MapperParsingException(
-                        "Could not dynamically add mapping for field [{}]. Existing mapping for [{}] must be of type object but found [{}].",
-                        null, String.join(".", paths), currentPath, existingFieldMapper.fieldType.typeName());
-            }
-            mapper = context.docMapper().objectMappers().get(currentPath);
-                if (mapper == null) {
-                    // One mapping is missing, check if we are allowed to create a dynamic one.
-                    ObjectMapper.Dynamic dynamic = dynamicOrDefault(parent, context);
+        ObjectMapper parent = mapper;
+        for (int i = 0; i < paths.length-1; i++) {
+        String currentPath = context.path().pathAsText(paths[i]);
+        Mapper existingFieldMapper = context.docMapper().mappers().getMapper(currentPath);
+        if (existingFieldMapper != null) {
+            throw new MapperParsingException(
+                    "Could not dynamically add mapping for field [{}]. Existing mapping for [{}] must be of type object but found [{}].",
+                    null, String.join(".", paths), currentPath, existingFieldMapper.typeName());
+        }
+        mapper = context.docMapper().objectMappers().get(currentPath);
+            if (mapper == null) {
+                // One mapping is missing, check if we are allowed to create a dynamic one.
+                ObjectMapper.Dynamic dynamic = dynamicOrDefault(parent, context);
 
-                    switch (dynamic) {
-                        case STRICT:
-                            throw new StrictDynamicMappingException(parent.fullPath(), paths[i]);
-                        case TRUE:
-                            Mapper.Builder builder = context.root().findTemplateBuilder(context, paths[i], XContentFieldType.OBJECT);
-                            if (builder == null) {
-                                builder = new ObjectMapper.Builder(paths[i]).enabled(true);
-                            }
-                            Mapper.BuilderContext builderContext = new Mapper.BuilderContext(context.indexSettings(), context.path());
-                            mapper = (ObjectMapper) builder.build(builderContext);
-                            if (mapper.nested() != ObjectMapper.Nested.NO) {
-                                throw new MapperParsingException("It is forbidden to create dynamic nested objects ([" + context.path().pathAsText(paths[i])
-                                        + "]) through `copy_to` or dots in field names");
-                            }
-                            context.addDynamicMapper(mapper);
-                            break;
-                        case FALSE:
-                           // Should not dynamically create any more mappers so return the last mapper
-                        return new Tuple<>(pathsAdded, parent);
+                switch (dynamic) {
+                    case STRICT:
+                        throw new StrictDynamicMappingException(parent.fullPath(), paths[i]);
+                    case TRUE:
+                        Mapper.Builder builder = context.root().findTemplateBuilder(context, paths[i], XContentFieldType.OBJECT);
+                        if (builder == null) {
+                            builder = new ObjectMapper.Builder(paths[i]).enabled(true);
+                        }
+                        Mapper.BuilderContext builderContext = new Mapper.BuilderContext(context.indexSettings(), context.path());
+                        mapper = (ObjectMapper) builder.build(builderContext);
+                        if (mapper.nested() != ObjectMapper.Nested.NO) {
+                            throw new MapperParsingException("It is forbidden to create dynamic nested objects ([" + context.path().pathAsText(paths[i])
+                                    + "]) through `copy_to` or dots in field names");
+                        }
+                        context.addDynamicMapper(mapper);
+                        break;
+                    case FALSE:
+                       // Should not dynamically create any more mappers so return the last mapper
+                    return new Tuple<>(pathsAdded, parent);
 
-                    }
                 }
-                context.path().add(paths[i]);
-                pathsAdded++;
-                parent = mapper;
             }
+            context.path().add(paths[i]);
+            pathsAdded++;
+            parent = mapper;
+        }
         return new Tuple<>(pathsAdded, mapper);
     }
 

server/src/main/java/org/elasticsearch/index/mapper/FieldAliasMapper.java

@@ -0,0 +1,132 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.index.mapper;
+
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.support.XContentMapValues;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.Map;
+
+/**
+ * A mapper for field aliases.
+ *
+ * A field alias has no concrete field mappings of its own, but instead points to another field by
+ * its path. Once defined, an alias can be used in place of the concrete field name in search requests.
+ */
+public final class FieldAliasMapper extends Mapper {
+    public static final String CONTENT_TYPE = "alias";
+
+    public static class Names {
+        public static final String PATH = "path";
+    }
+
+    private final String name;
+    private final String path;
+
+    public FieldAliasMapper(String simpleName,
+                            String name,
+                            String path) {
+        super(simpleName);
+        this.name = name;
+        this.path = path;
+    }
+
+    @Override
+    public String name() {
+        return name;
+    }
+
+    @Override
+    public String typeName() {
+        return CONTENT_TYPE;
+    }
+
+    public String path() {
+        return path;
+    }
+
+    @Override
+    public Mapper merge(Mapper mergeWith) {
+        if (!(mergeWith instanceof FieldAliasMapper)) {
+            throw new IllegalArgumentException("Cannot merge a field alias mapping ["
+                + name() + "] with a mapping that is not for a field alias.");
+        }
+        return mergeWith;
+    }
+
+    @Override
+    public Mapper updateFieldType(Map<String, MappedFieldType> fullNameToFieldType) {
+        return this;
+    }
+
+    @Override
+    public Iterator<Mapper> iterator() {
+        return Collections.emptyIterator();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.startObject(simpleName())
+            .field("type", CONTENT_TYPE)
+            .field(Names.PATH, path)
+            .endObject();
+    }
+
+    public static class TypeParser implements Mapper.TypeParser {
+        @Override
+        public Mapper.Builder parse(String name, Map<String, Object> node, ParserContext parserContext)
+            throws MapperParsingException {
+            FieldAliasMapper.Builder builder = new FieldAliasMapper.Builder(name);
+            Object pathField = node.remove(Names.PATH);
+            String path = XContentMapValues.nodeStringValue(pathField, null);
+            if (path == null) {
+                throw new MapperParsingException("The [path] property must be specified for field [" + name + "].");
+            }
+            return builder.path(path);
+        }
+    }
+
+    public static class Builder extends Mapper.Builder<FieldAliasMapper.Builder, FieldAliasMapper> {
+        private String name;
+        private String path;
+
+        protected Builder(String name) {
+            super(name);
+            this.name = name;
+        }
+
+        public String name() {
+            return this.name;
+        }
+
+        public Builder path(String path) {
+            this.path = path;
+            return this;
+        }
+
+        public FieldAliasMapper build(BuilderContext context) {
+            String fullName = context.path().pathAsText(name);
+            return new FieldAliasMapper(name, fullName, path);
+        }
+    }
+}

server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java

@@ -247,6 +247,11 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
         return fieldType().name();
     }
 
+    @Override
+    public String typeName() {
+        return fieldType.typeName();
+    }
+
     public MappedFieldType fieldType() {
         return fieldType;
     }

server/src/main/java/org/elasticsearch/index/mapper/FieldTypeLookup.java

@@ -35,64 +35,115 @@ import java.util.Set;
  */
 class FieldTypeLookup implements Iterable<MappedFieldType> {
 
-    /** Full field name to field type */
     final CopyOnWriteHashMap<String, MappedFieldType> fullNameToFieldType;
+    private final CopyOnWriteHashMap<String, String> aliasToConcreteName;
 
-    /** Create a new empty instance. */
     FieldTypeLookup() {
         fullNameToFieldType = new CopyOnWriteHashMap<>();
+        aliasToConcreteName = new CopyOnWriteHashMap<>();
     }
 
-    private FieldTypeLookup(CopyOnWriteHashMap<String, MappedFieldType> fullName) {
-        this.fullNameToFieldType = fullName;
+    private FieldTypeLookup(CopyOnWriteHashMap<String, MappedFieldType> fullNameToFieldType,
+                            CopyOnWriteHashMap<String, String> aliasToConcreteName) {
+        this.fullNameToFieldType = fullNameToFieldType;
+        this.aliasToConcreteName = aliasToConcreteName;
     }
 
     /**
      * Return a new instance that contains the union of this instance and the field types
-     * from the provided fields. If a field already exists, the field type will be updated
-     * to use the new mappers field type.
+     * from the provided mappers. If a field already exists, its field type will be updated
+     * to use the new type from the given field mapper. Similarly if an alias already
+     * exists, it will be updated to reference the field type from the new mapper.
      */
-    public FieldTypeLookup copyAndAddAll(String type, Collection<FieldMapper> fieldMappers) {
+    public FieldTypeLookup copyAndAddAll(String type,
+                                         Collection<FieldMapper> fieldMappers,
+                                         Collection<FieldAliasMapper> fieldAliasMappers) {
         Objects.requireNonNull(type, "type must not be null");
         if (MapperService.DEFAULT_MAPPING.equals(type)) {
             throw new IllegalArgumentException("Default mappings should not be added to the lookup");
         }
 
         CopyOnWriteHashMap<String, MappedFieldType> fullName = this.fullNameToFieldType;
+        CopyOnWriteHashMap<String, String> aliases = this.aliasToConcreteName;
 
         for (FieldMapper fieldMapper : fieldMappers) {
             MappedFieldType fieldType = fieldMapper.fieldType();
             MappedFieldType fullNameFieldType = fullName.get(fieldType.name());
 
-            if (fullNameFieldType == null) {
-                // introduction of a new field
-                fullName = fullName.copyAndPut(fieldType.name(), fieldMapper.fieldType());
-            } else {
-                // modification of an existing field
-                checkCompatibility(fullNameFieldType, fieldType);
-                if (fieldType.equals(fullNameFieldType) == false) {
-                    fullName = fullName.copyAndPut(fieldType.name(), fieldMapper.fieldType());
-                }
+            if (!Objects.equals(fieldType, fullNameFieldType)) {
+                validateField(fullNameFieldType, fieldType, aliases);
+                fullName = fullName.copyAndPut(fieldType.name(), fieldType);
             }
         }
-        return new FieldTypeLookup(fullName);
+
+        for (FieldAliasMapper fieldAliasMapper : fieldAliasMappers) {
+            String aliasName = fieldAliasMapper.name();
+            String path = fieldAliasMapper.path();
+
+            validateAlias(aliasName, path, aliases, fullName);
+            aliases = aliases.copyAndPut(aliasName, path);
+        }
+
+        return new FieldTypeLookup(fullName, aliases);
     }
 
     /**
-     * Checks if the given field type is compatible with an existing field type.
-     * An IllegalArgumentException is thrown in case of incompatibility.
+     * Checks that the new field type is valid.
      */
-    private void checkCompatibility(MappedFieldType existingFieldType, MappedFieldType newFieldType) {
-        List<String> conflicts = new ArrayList<>();
-        existingFieldType.checkCompatibility(newFieldType, conflicts);
-        if (conflicts.isEmpty() == false) {
-            throw new IllegalArgumentException("Mapper for [" + newFieldType.name() + "] conflicts with existing mapping:\n" + conflicts.toString());
+    private void validateField(MappedFieldType existingFieldType,
+                               MappedFieldType newFieldType,
+                               CopyOnWriteHashMap<String, String> aliasToConcreteName) {
+        String fieldName = newFieldType.name();
+        if (aliasToConcreteName.containsKey(fieldName)) {
+            throw new IllegalArgumentException("The name for field [" + fieldName + "] has already" +
+                " been used to define a field alias.");
+        }
+
+        if (existingFieldType != null) {
+            List<String> conflicts = new ArrayList<>();
+            existingFieldType.checkCompatibility(newFieldType, conflicts);
+            if (conflicts.isEmpty() == false) {
+                throw new IllegalArgumentException("Mapper for [" + fieldName +
+                    "] conflicts with existing mapping:\n" + conflicts.toString());
+            }
+        }
+    }
+
+    /**
+     * Checks that the new field alias is valid.
+     *
+     * Note that this method assumes that new concrete fields have already been processed, so that it
+     * can verify that an alias refers to an existing concrete field.
+     */
+    private void validateAlias(String aliasName,
+                               String path,
+                               CopyOnWriteHashMap<String, String> aliasToConcreteName,
+                               CopyOnWriteHashMap<String, MappedFieldType> fullNameToFieldType) {
+        if (fullNameToFieldType.containsKey(aliasName)) {
+            throw new IllegalArgumentException("The name for field alias [" + aliasName + "] has already" +
+                " been used to define a concrete field.");
+        }
+
+        if (path.equals(aliasName)) {
+            throw new IllegalArgumentException("Invalid [path] value [" + path + "] for field alias [" +
+                aliasName + "]: an alias cannot refer to itself.");
+        }
+
+        if (aliasToConcreteName.containsKey(path)) {
+            throw new IllegalArgumentException("Invalid [path] value [" + path + "] for field alias [" +
+                aliasName + "]: an alias cannot refer to another alias.");
+        }
+
+        if (!fullNameToFieldType.containsKey(path)) {
+            throw new IllegalArgumentException("Invalid [path] value [" + path + "] for field alias [" +
+                aliasName + "]: an alias must refer to an existing field in the mappings.");
         }
     }
 
     /** Returns the field for the given field */
     public MappedFieldType get(String field) {
-        return fullNameToFieldType.get(field);
+        String concreteField = aliasToConcreteName.getOrDefault(field, field);
+        return fullNameToFieldType.get(concreteField);
     }
 
     /**
@@ -105,6 +156,11 @@ class FieldTypeLookup implements Iterable<MappedFieldType> {
                 fields.add(fieldType.name());
             }
         }
+        for (String aliasName : aliasToConcreteName.keySet()) {
+            if (Regex.simpleMatch(pattern, aliasName)) {
+                fields.add(aliasName);
+            }
+        }
         return fields;
     }
 

server/src/main/java/org/elasticsearch/index/mapper/Mapper.java

@@ -173,6 +173,11 @@ public abstract class Mapper implements ToXContentFragment, Iterable<Mapper> {
     /** Returns the canonical name which uniquely identifies the mapper against other mappers in a type. */
     public abstract String name();
 
+    /**
+     * Returns a name representing the the type of this mapper.
+     */
+    public abstract String typeName();
+
     /** Return the merge of {@code mergeWith} into this.
      *  Both {@code this} and {@code mergeWith} will be left unmodified. */
     public abstract Mapper merge(Mapper mergeWith);

server/src/main/java/org/elasticsearch/index/mapper/MapperMergeValidator.java

@@ -0,0 +1,214 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.index.mapper;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Stream;
+
+/**
+ * A utility class that helps validate certain aspects of a mappings update.
+ */
+class MapperMergeValidator {
+
+    /**
+     * Validates the overall structure of the mapping addition, including whether
+     * duplicate fields are present, and if the provided fields have already been
+     * defined with a different data type.
+     *
+     * @param type The mapping type, for use in error messages.
+     * @param objectMappers The newly added object mappers.
+     * @param fieldMappers The newly added field mappers.
+     * @param fieldAliasMappers The newly added field alias mappers.
+     * @param fullPathObjectMappers All object mappers, indexed by their full path.
+     * @param fieldTypes All field and field alias mappers, collected into a lookup structure.
+     */
+    public static void validateMapperStructure(String type,
+                                               Collection<ObjectMapper> objectMappers,
+                                               Collection<FieldMapper> fieldMappers,
+                                               Collection<FieldAliasMapper> fieldAliasMappers,
+                                               Map<String, ObjectMapper> fullPathObjectMappers,
+                                               FieldTypeLookup fieldTypes) {
+        checkFieldUniqueness(type, objectMappers, fieldMappers,
+            fieldAliasMappers, fullPathObjectMappers, fieldTypes);
+        checkObjectsCompatibility(objectMappers, fullPathObjectMappers);
+    }
+
+    private static void checkFieldUniqueness(String type,
+                                             Collection<ObjectMapper> objectMappers,
+                                             Collection<FieldMapper> fieldMappers,
+                                             Collection<FieldAliasMapper> fieldAliasMappers,
+                                             Map<String, ObjectMapper> fullPathObjectMappers,
+                                             FieldTypeLookup fieldTypes) {
+
+        // first check within mapping
+        Set<String> objectFullNames = new HashSet<>();
+        for (ObjectMapper objectMapper : objectMappers) {
+            String fullPath = objectMapper.fullPath();
+            if (objectFullNames.add(fullPath) == false) {
+                throw new IllegalArgumentException("Object mapper [" + fullPath + "] is defined twice in mapping for type [" + type + "]");
+            }
+        }
+
+        Set<String> fieldNames = new HashSet<>();
+        Stream.concat(fieldMappers.stream(), fieldAliasMappers.stream())
+            .forEach(mapper -> {
+                String name = mapper.name();
+                if (objectFullNames.contains(name)) {
+                    throw new IllegalArgumentException("Field [" + name + "] is defined both as an object and a field in [" + type + "]");
+                } else if (fieldNames.add(name) == false) {
+                    throw new IllegalArgumentException("Field [" + name + "] is defined twice in [" + type + "]");
+                }
+            });
+
+        // then check other types
+        for (String fieldName : fieldNames) {
+            if (fullPathObjectMappers.containsKey(fieldName)) {
+                throw new IllegalArgumentException("[" + fieldName + "] is defined as a field in mapping [" + type
+                    + "] but this name is already used for an object in other types");
+            }
+        }
+
+        for (String objectPath : objectFullNames) {
+            if (fieldTypes.get(objectPath) != null) {
+                throw new IllegalArgumentException("[" + objectPath + "] is defined as an object in mapping [" + type
+                    + "] but this name is already used for a field in other types");
+            }
+        }
+    }
+
+    private static void checkObjectsCompatibility(Collection<ObjectMapper> objectMappers,
+                                                  Map<String, ObjectMapper> fullPathObjectMappers) {
+        for (ObjectMapper newObjectMapper : objectMappers) {
+            ObjectMapper existingObjectMapper = fullPathObjectMappers.get(newObjectMapper.fullPath());
+            if (existingObjectMapper != null) {
+                // simulate a merge and ignore the result, we are just interested
+                // in exceptions here
+                existingObjectMapper.merge(newObjectMapper);
+            }
+        }
+    }
+
+    /**
+     * Verifies that each field reference, e.g. the value of copy_to or the target
+     * of a field alias, corresponds to a valid part of the mapping.
+     *
+     * @param fieldMappers The newly added field mappers.
+     * @param fieldAliasMappers The newly added field alias mappers.
+     * @param fullPathObjectMappers All object mappers, indexed by their full path.
+     * @param fieldTypes All field and field alias mappers, collected into a lookup structure.
+     */
+    public static void validateFieldReferences(List<FieldMapper> fieldMappers,
+                                               List<FieldAliasMapper> fieldAliasMappers,
+                                               Map<String, ObjectMapper> fullPathObjectMappers,
+                                               FieldTypeLookup fieldTypes) {
+        validateCopyTo(fieldMappers, fullPathObjectMappers, fieldTypes);
+        validateFieldAliasTargets(fieldAliasMappers, fullPathObjectMappers);
+    }
+
+    private static void validateCopyTo(List<FieldMapper> fieldMappers,
+                                       Map<String, ObjectMapper> fullPathObjectMappers,
+                                       FieldTypeLookup fieldTypes) {
+        for (FieldMapper mapper : fieldMappers) {
+            if (mapper.copyTo() != null && mapper.copyTo().copyToFields().isEmpty() == false) {
+                String sourceParent = parentObject(mapper.name());
+                if (sourceParent != null && fieldTypes.get(sourceParent) != null) {
+                    throw new IllegalArgumentException("[copy_to] may not be used to copy from a multi-field: [" + mapper.name() + "]");
+                }
+
+                final String sourceScope = getNestedScope(mapper.name(), fullPathObjectMappers);
+                for (String copyTo : mapper.copyTo().copyToFields()) {
+                    String copyToParent = parentObject(copyTo);
+                    if (copyToParent != null && fieldTypes.get(copyToParent) != null) {
+                        throw new IllegalArgumentException("[copy_to] may not be used to copy to a multi-field: [" + copyTo + "]");
+                    }
+
+                    if (fullPathObjectMappers.containsKey(copyTo)) {
+                        throw new IllegalArgumentException("Cannot copy to field [" + copyTo + "] since it is mapped as an object");
+                    }
+
+                    final String targetScope = getNestedScope(copyTo, fullPathObjectMappers);
+                    checkNestedScopeCompatibility(sourceScope, targetScope);
+                }
+            }
+        }
+    }
+
+    private static void validateFieldAliasTargets(List<FieldAliasMapper> fieldAliasMappers,
+                                                  Map<String, ObjectMapper> fullPathObjectMappers) {
+        for (FieldAliasMapper mapper : fieldAliasMappers) {
+            String aliasName = mapper.name();
+            String path = mapper.path();
+
+            String aliasScope = getNestedScope(aliasName, fullPathObjectMappers);
+            String pathScope = getNestedScope(path, fullPathObjectMappers);
+
+            if (!Objects.equals(aliasScope, pathScope)) {
+                StringBuilder message = new StringBuilder("Invalid [path] value [" + path + "] for field alias [" +
+                    aliasName + "]: an alias must have the same nested scope as its target. ");
+                message.append(aliasScope == null
+                    ? "The alias is not nested"
+                    : "The alias's nested scope is [" + aliasScope + "]");
+                message.append(", but ");
+                message.append(pathScope == null
+                    ? "the target is not nested."
+                    : "the target's nested scope is [" + pathScope + "].");
+                throw new IllegalArgumentException(message.toString());
+            }
+        }
+    }
+
+    private static String getNestedScope(String path, Map<String, ObjectMapper> fullPathObjectMappers) {
+        for (String parentPath = parentObject(path); parentPath != null; parentPath = parentObject(parentPath)) {
+            ObjectMapper objectMapper = fullPathObjectMappers.get(parentPath);
+            if (objectMapper != null && objectMapper.nested().isNested()) {
+                return parentPath;
+            }
+        }
+        return null;
+    }
+
+    private static void checkNestedScopeCompatibility(String source, String target) {
+        boolean targetIsParentOfSource;
+        if (source == null || target == null) {
+            targetIsParentOfSource = target == null;
+        } else {
+            targetIsParentOfSource = source.equals(target) || source.startsWith(target + ".");
+        }
+        if (targetIsParentOfSource == false) {
+            throw new IllegalArgumentException(
+                "Illegal combination of [copy_to] and [nested] mappings: [copy_to] may only copy data to the current nested " +
+                    "document or any of its parents, however one [copy_to] directive is trying to copy data from nested object [" +
+                    source + "] to [" + target + "]");
+        }
+    }
+
+    private static String parentObject(String field) {
+        int lastDot = field.lastIndexOf('.');
+        if (lastDot == -1) {
+            return null;
+        }
+        return field.substring(0, lastDot);
+    }
+}

server/src/main/java/org/elasticsearch/index/mapper/MapperService.java

@@ -21,7 +21,6 @@ package org.elasticsearch.index.mapper;
 
 import com.carrotsearch.hppc.ObjectHashSet;
 import com.carrotsearch.hppc.cursors.ObjectCursor;
-
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.DelegatingAnalyzerWrapper;
@@ -395,15 +394,17 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
             // check basic sanity of the new mapping
             List<ObjectMapper> objectMappers = new ArrayList<>();
             List<FieldMapper> fieldMappers = new ArrayList<>();
+            List<FieldAliasMapper> fieldAliasMappers = new ArrayList<>();
             Collections.addAll(fieldMappers, newMapper.mapping().metadataMappers);
-            MapperUtils.collect(newMapper.mapping().root(), objectMappers, fieldMappers);
-            checkFieldUniqueness(newMapper.type(), objectMappers, fieldMappers, fullPathObjectMappers, fieldTypes);
-            checkObjectsCompatibility(objectMappers, fullPathObjectMappers);
+            MapperUtils.collect(newMapper.mapping().root(), objectMappers, fieldMappers, fieldAliasMappers);
+
+            MapperMergeValidator.validateMapperStructure(newMapper.type(), objectMappers, fieldMappers,
+                fieldAliasMappers, fullPathObjectMappers, fieldTypes);
             checkPartitionedIndexConstraints(newMapper);
 
             // update lookup data-structures
             // this will in particular make sure that the merged fields are compatible with other types
-            fieldTypes = fieldTypes.copyAndAddAll(newMapper.type(), fieldMappers);
+            fieldTypes = fieldTypes.copyAndAddAll(newMapper.type(), fieldMappers, fieldAliasMappers);
 
             for (ObjectMapper objectMapper : objectMappers) {
                 if (fullPathObjectMappers == this.fullPathObjectMappers) {
@@ -417,7 +418,8 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
                 }
             }
 
-            validateCopyTo(fieldMappers, fullPathObjectMappers, fieldTypes);
+            MapperMergeValidator.validateFieldReferences(fieldMappers, fieldAliasMappers,
+                fullPathObjectMappers, fieldTypes);
 
             if (reason == MergeReason.MAPPING_UPDATE) {
                 // this check will only be performed on the master node when there is
@@ -482,7 +484,7 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
         if (mapper != null) {
             List<FieldMapper> fieldMappers = new ArrayList<>();
             Collections.addAll(fieldMappers, mapper.mapping().metadataMappers);
-            MapperUtils.collect(mapper.root(), new ArrayList<>(), fieldMappers);
+            MapperUtils.collect(mapper.root(), new ArrayList<>(), fieldMappers, new ArrayList<>());
             for (FieldMapper fieldMapper : fieldMappers) {
                 assert fieldMapper.fieldType() == fieldTypes.get(fieldMapper.name()) : fieldMapper.name();
             }
@@ -503,56 +505,6 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
         return true;
     }
 
-    private static void checkFieldUniqueness(String type, Collection<ObjectMapper> objectMappers, Collection<FieldMapper> fieldMappers,
-                                             Map<String, ObjectMapper> fullPathObjectMappers, FieldTypeLookup fieldTypes) {
-
-        // first check within mapping
-        final Set<String> objectFullNames = new HashSet<>();
-        for (ObjectMapper objectMapper : objectMappers) {
-            final String fullPath = objectMapper.fullPath();
-            if (objectFullNames.add(fullPath) == false) {
-                throw new IllegalArgumentException("Object mapper [" + fullPath + "] is defined twice in mapping for type [" + type + "]");
-            }
-        }
-
-        final Set<String> fieldNames = new HashSet<>();
-        for (FieldMapper fieldMapper : fieldMappers) {
-            final String name = fieldMapper.name();
-            if (objectFullNames.contains(name)) {
-                throw new IllegalArgumentException("Field [" + name + "] is defined both as an object and a field in [" + type + "]");
-            } else if (fieldNames.add(name) == false) {
-                throw new IllegalArgumentException("Field [" + name + "] is defined twice in [" + type + "]");
-            }
-        }
-
-        // then check other types
-        for (String fieldName : fieldNames) {
-            if (fullPathObjectMappers.containsKey(fieldName)) {
-                throw new IllegalArgumentException("[" + fieldName + "] is defined as a field in mapping [" + type
-                        + "] but this name is already used for an object in other types");
-            }
-        }
-
-        for (String objectPath : objectFullNames) {
-            if (fieldTypes.get(objectPath) != null) {
-                throw new IllegalArgumentException("[" + objectPath + "] is defined as an object in mapping [" + type
-                        + "] but this name is already used for a field in other types");
-            }
-        }
-    }
-
-    private static void checkObjectsCompatibility(Collection<ObjectMapper> objectMappers,
-                                                  Map<String, ObjectMapper> fullPathObjectMappers) {
-        for (ObjectMapper newObjectMapper : objectMappers) {
-            ObjectMapper existingObjectMapper = fullPathObjectMappers.get(newObjectMapper.fullPath());
-            if (existingObjectMapper != null) {
-                // simulate a merge and ignore the result, we are just interested
-                // in exceptions here
-                existingObjectMapper.merge(newObjectMapper);
-            }
-        }
-    }
-
     private void checkNestedFieldsLimit(Map<String, ObjectMapper> fullPathObjectMappers) {
         long allowedNestedFields = indexSettings.getValue(INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING);
         long actualNestedFields = 0;
@@ -609,66 +561,6 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
         }
     }
 
-    private static void validateCopyTo(List<FieldMapper> fieldMappers, Map<String, ObjectMapper> fullPathObjectMappers,
-            FieldTypeLookup fieldTypes) {
-        for (FieldMapper mapper : fieldMappers) {
-            if (mapper.copyTo() != null && mapper.copyTo().copyToFields().isEmpty() == false) {
-                String sourceParent = parentObject(mapper.name());
-                if (sourceParent != null && fieldTypes.get(sourceParent) != null) {
-                    throw new IllegalArgumentException("[copy_to] may not be used to copy from a multi-field: [" + mapper.name() + "]");
-                }
-
-                final String sourceScope = getNestedScope(mapper.name(), fullPathObjectMappers);
-                for (String copyTo : mapper.copyTo().copyToFields()) {
-                    String copyToParent = parentObject(copyTo);
-                    if (copyToParent != null && fieldTypes.get(copyToParent) != null) {
-                        throw new IllegalArgumentException("[copy_to] may not be used to copy to a multi-field: [" + copyTo + "]");
-                    }
-
-                    if (fullPathObjectMappers.containsKey(copyTo)) {
-                        throw new IllegalArgumentException("Cannot copy to field [" + copyTo + "] since it is mapped as an object");
-                    }
-
-                    final String targetScope = getNestedScope(copyTo, fullPathObjectMappers);
-                    checkNestedScopeCompatibility(sourceScope, targetScope);
-                }
-            }
-        }
-    }
-
-    private static String getNestedScope(String path, Map<String, ObjectMapper> fullPathObjectMappers) {
-        for (String parentPath = parentObject(path); parentPath != null; parentPath = parentObject(parentPath)) {
-            ObjectMapper objectMapper = fullPathObjectMappers.get(parentPath);
-            if (objectMapper != null && objectMapper.nested().isNested()) {
-                return parentPath;
-            }
-        }
-        return null;
-    }
-
-    private static void checkNestedScopeCompatibility(String source, String target) {
-        boolean targetIsParentOfSource;
-        if (source == null || target == null) {
-            targetIsParentOfSource = target == null;
-        } else {
-            targetIsParentOfSource = source.equals(target) || source.startsWith(target + ".");
-        }
-        if (targetIsParentOfSource == false) {
-            throw new IllegalArgumentException(
-                    "Illegal combination of [copy_to] and [nested] mappings: [copy_to] may only copy data to the current nested " +
-                            "document or any of its parents, however one [copy_to] directive is trying to copy data from nested object [" +
-                            source + "] to [" + target + "]");
-        }
-    }
-
-    private static String parentObject(String field) {
-        int lastDot = field.lastIndexOf('.');
-        if (lastDot == -1) {
-            return null;
-        }
-        return field.substring(0, lastDot);
-    }
-
     public DocumentMapper parse(String mappingType, CompressedXContent mappingSource, boolean applyDefault) throws MapperParsingException {
         return documentParser.parse(mappingType, mappingSource, applyDefault ? defaultMappingSource : null);
     }
@@ -729,6 +621,13 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
         return fieldTypes.simpleMatchToFullName(pattern);
     }
 
+    /**
+     * Returns all mapped field types.
+     */
+    public Iterable<MappedFieldType> fieldTypes() {
+        return fieldTypes;
+    }
+
     public ObjectMapper getObjectMapper(String name) {
         return fullPathObjectMappers.get(name);
     }

server/src/main/java/org/elasticsearch/index/mapper/MapperUtils.java

@@ -24,17 +24,28 @@ import java.util.Collection;
 enum MapperUtils {
     ;
 
-    /** Split mapper and its descendants into object and field mappers. */
-    public static void collect(Mapper mapper, Collection<ObjectMapper> objectMappers, Collection<FieldMapper> fieldMappers) {
+    /**
+     * Splits the provided mapper and its descendants into object, field, and field alias mappers.
+     */
+    public static void collect(Mapper mapper, Collection<ObjectMapper> objectMappers,
+                               Collection<FieldMapper> fieldMappers,
+                               Collection<FieldAliasMapper> fieldAliasMappers) {
         if (mapper instanceof RootObjectMapper) {
             // root mapper isn't really an object mapper
         } else if (mapper instanceof ObjectMapper) {
             objectMappers.add((ObjectMapper)mapper);
         } else if (mapper instanceof FieldMapper) {
             fieldMappers.add((FieldMapper)mapper);
+        } else if (mapper instanceof FieldAliasMapper) {
+            fieldAliasMappers.add((FieldAliasMapper) mapper);
+        } else {
+            throw new IllegalStateException("Unrecognized mapper type [" +
+                mapper.getClass().getSimpleName() + "].");
         }
+
+
         for (Mapper child : mapper) {
-            collect(child, objectMappers, fieldMappers);
+            collect(child, objectMappers, fieldMappers, fieldAliasMappers);
         }
     }
 }

server/src/main/java/org/elasticsearch/index/mapper/ObjectMapper.java

@@ -359,6 +359,11 @@ public class ObjectMapper extends Mapper implements Cloneable {
         return this.fullPath;
     }
 
+    @Override
+    public String typeName() {
+        return CONTENT_TYPE;
+    }
+
     public boolean isEnabled() {
         return this.enabled;
     }

server/src/main/java/org/elasticsearch/index/query/ExistsQueryBuilder.java

@@ -149,7 +149,7 @@ public class ExistsQueryBuilder extends AbstractQueryBuilder<ExistsQueryBuilder>
         }
 
         if (context.indexVersionCreated().before(Version.V_6_1_0)) {
-            return newLegacyExistsQuery(fields);
+            return newLegacyExistsQuery(context, fields);
         }
 
         if (fields.size() == 1) {
@@ -164,22 +164,28 @@ public class ExistsQueryBuilder extends AbstractQueryBuilder<ExistsQueryBuilder>
         return new ConstantScoreQuery(boolFilterBuilder.build());
     }
 
-    private static Query newLegacyExistsQuery(Collection<String> fields) {
+    private static Query newLegacyExistsQuery(QueryShardContext context, Collection<String> fields) {
         // We create TermsQuery directly here rather than using FieldNamesFieldType.termsQuery()
         // so we don't end up with deprecation warnings
         if (fields.size() == 1) {
-            Query filter = new TermQuery(new Term(FieldNamesFieldMapper.NAME, fields.iterator().next()));
+            Query filter = newLegacyExistsQuery(context, fields.iterator().next());
             return new ConstantScoreQuery(filter);
         }
 
         BooleanQuery.Builder boolFilterBuilder = new BooleanQuery.Builder();
         for (String field : fields) {
-            Query filter = new TermQuery(new Term(FieldNamesFieldMapper.NAME, field));
+            Query filter = newLegacyExistsQuery(context, field);
             boolFilterBuilder.add(filter, BooleanClause.Occur.SHOULD);
         }
         return new ConstantScoreQuery(boolFilterBuilder.build());
     }
 
+    private static Query newLegacyExistsQuery(QueryShardContext context, String field) {
+        MappedFieldType fieldType = context.fieldMapper(field);
+        String fieldName = fieldType != null ? fieldType.name() : field;
+        return new TermQuery(new Term(FieldNamesFieldMapper.NAME, fieldName));
+    }
+
     private static Query newFieldExistsQuery(QueryShardContext context, String field) {
         MappedFieldType fieldType = context.getMapperService().fullName(field);
         if (fieldType == null) {

server/src/main/java/org/elasticsearch/index/query/SpanMultiTermQueryBuilder.java

@@ -44,6 +44,7 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.query.support.QueryParsers;
 
 import java.io.IOException;
@@ -202,14 +203,18 @@ public class SpanMultiTermQueryBuilder extends AbstractQueryBuilder<SpanMultiTer
                     multiTermQueryBuilder.getClass().getName() + ", should be " + MultiTermQuery.class.getName()
                     + " but was " + subQuery.getClass().getName());
             }
+
+            PrefixQueryBuilder prefixBuilder = (PrefixQueryBuilder) multiTermQueryBuilder;
+            MappedFieldType fieldType = context.fieldMapper(prefixBuilder.fieldName());
+            String fieldName = fieldType != null ? fieldType.name() : prefixBuilder.fieldName();
+
             if (context.getIndexSettings().getIndexVersionCreated().before(Version.V_6_4_0)) {
                 /**
                  * Indices created in this version do not index positions on the prefix field
                  * so we cannot use it to match positional queries. Instead, we explicitly create the prefix
                  * query on the main field to avoid the rewrite.
                  */
-                PrefixQueryBuilder prefixBuilder = (PrefixQueryBuilder) multiTermQueryBuilder;
-                PrefixQuery prefixQuery = new PrefixQuery(new Term(prefixBuilder.fieldName(), prefixBuilder.value()));
+                PrefixQuery prefixQuery = new PrefixQuery(new Term(fieldName, prefixBuilder.value()));
                 if (prefixBuilder.rewrite() != null) {
                     MultiTermQuery.RewriteMethod rewriteMethod =
                         QueryParsers.parseRewriteMethod(prefixBuilder.rewrite(), null, LoggingDeprecationHandler.INSTANCE);
@@ -218,15 +223,14 @@ public class SpanMultiTermQueryBuilder extends AbstractQueryBuilder<SpanMultiTer
                 subQuery = prefixQuery;
                 spanQuery = new SpanMultiTermQueryWrapper<>(prefixQuery);
             } else {
-                String origFieldName = ((PrefixQueryBuilder) multiTermQueryBuilder).fieldName();
-                SpanTermQuery spanTermQuery = new SpanTermQuery(((TermQuery) subQuery).getTerm());
                 /**
                  * Prefixes are indexed in a different field so we mask the term query with the original field
                  * name. This is required because span_near and span_or queries don't work across different field.
                  * The masking is safe because the prefix field is indexed using the same content than the original field
                  * and the prefix analyzer preserves positions.
                  */
-                spanQuery = new FieldMaskingSpanQuery(spanTermQuery, origFieldName);
+                SpanTermQuery spanTermQuery = new SpanTermQuery(((TermQuery) subQuery).getTerm());
+                spanQuery = new FieldMaskingSpanQuery(spanTermQuery, fieldName);
             }
         } else {
             if (subQuery instanceof MultiTermQuery == false) {

server/src/main/java/org/elasticsearch/index/query/SpanNearQueryBuilder.java

@@ -30,6 +30,7 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentLocation;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.index.mapper.MappedFieldType;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -218,7 +219,8 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
         }
         String spanNearFieldName = null;
         if (isGap) {
-            spanNearFieldName = ((SpanGapQueryBuilder) queryBuilder).fieldName();
+            String fieldName = ((SpanGapQueryBuilder) queryBuilder).fieldName();
+            spanNearFieldName = queryFieldName(context, fieldName);
         } else {
             spanNearFieldName = ((SpanQuery) query).getField();
         }
@@ -241,7 +243,9 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
             isGap = queryBuilder instanceof SpanGapQueryBuilder;
             if (isGap) {
                 String fieldName = ((SpanGapQueryBuilder) queryBuilder).fieldName();
-                if (!spanNearFieldName.equals(fieldName)) {
+                String spanGapFieldName = queryFieldName(context, fieldName);
+
+                if (!spanNearFieldName.equals(spanGapFieldName)) {
                     throw new IllegalArgumentException("[span_near] clauses must have same field");
                 }
                 int gap = ((SpanGapQueryBuilder) queryBuilder).width();
@@ -255,6 +259,11 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
         return builder.build();
     }
 
+    private String queryFieldName(QueryShardContext context, String fieldName) {
+        MappedFieldType fieldType = context.fieldMapper(fieldName);
+        return fieldType != null ? fieldType.name() : fieldName;
+    }
+
     @Override
     protected int doHashCode() {
         return Objects.hash(clauses, slop, inOrder);
@@ -273,11 +282,11 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
     }
 
     /**
-     * SpanGapQueryBuilder enables gaps in a SpanNearQuery. 
+     * SpanGapQueryBuilder enables gaps in a SpanNearQuery.
      * Since, SpanGapQuery is private to SpanNearQuery, SpanGapQueryBuilder cannot
      * be used to generate a Query (SpanGapQuery) like another QueryBuilder.
-     * Instead, it just identifies a span_gap clause so that SpanNearQuery.addGap(int) 
-     * can be invoked for it. 
+     * Instead, it just identifies a span_gap clause so that SpanNearQuery.addGap(int)
+     * can be invoked for it.
      * This QueryBuilder is only applicable as a clause in SpanGapQueryBuilder but
      * yet to enforce this restriction.
      */
@@ -286,9 +295,9 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
 
         /** Name of field to match against. */
         private final String fieldName;
-    
+
         /** Width of the gap introduced. */
-        private final int width; 
+        private final int width;
 
         /**
          * Constructs a new SpanGapQueryBuilder term query.
@@ -301,7 +310,7 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
                 throw new IllegalArgumentException("[span_gap] field name is null or empty");
             }
             //lucene has not coded any restriction on value of width.
-            //to-do : find if theoretically it makes sense to apply restrictions. 
+            //to-do : find if theoretically it makes sense to apply restrictions.
             this.fieldName = fieldName;
             this.width = width;
         }
@@ -396,7 +405,7 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
                     fieldName = currentFieldName;
                 } else if (token.isValue()) {
                     width = parser.intValue();
-                } 
+                }
             }
             SpanGapQueryBuilder result = new SpanGapQueryBuilder(fieldName, width);
             return result;
@@ -420,7 +429,7 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
             return Objects.hash(getClass(), fieldName, width);
         }
 
-        
+
         @Override
         public final String toString() {
             return Strings.toString(this, true, true);

server/src/main/java/org/elasticsearch/index/query/TermsSetQueryBuilder.java

@@ -221,7 +221,7 @@ public final class TermsSetQueryBuilder extends AbstractQueryBuilder<TermsSetQue
     }
 
     @Override
-    protected Query doToQuery(QueryShardContext context) throws IOException {
+    protected Query doToQuery(QueryShardContext context) {
         if (values.isEmpty()) {
             return Queries.newMatchNoDocsQuery("No terms supplied for \"" + getName() + "\" query.");
         }
@@ -230,6 +230,15 @@ public final class TermsSetQueryBuilder extends AbstractQueryBuilder<TermsSetQue
             throw new BooleanQuery.TooManyClauses();
         }
 
+        List<Query> queries = createTermQueries(context);
+        LongValuesSource longValuesSource = createValuesSource(context);
+        return new CoveringQuery(queries, longValuesSource);
+    }
+
+    /**
+     * Visible only for testing purposes.
+     */
+    List<Query> createTermQueries(QueryShardContext context) {
         final MappedFieldType fieldType = context.fieldMapper(fieldName);
         final List<Query> queries = new ArrayList<>(values.size());
         for (Object value : values) {
@@ -239,7 +248,11 @@ public final class TermsSetQueryBuilder extends AbstractQueryBuilder<TermsSetQue
                 queries.add(new TermQuery(new Term(fieldName, BytesRefs.toBytesRef(value))));
             }
         }
-        final LongValuesSource longValuesSource;
+        return queries;
+    }
+
+    private LongValuesSource createValuesSource(QueryShardContext context) {
+        LongValuesSource longValuesSource;
         if (minimumShouldMatchField != null) {
             MappedFieldType msmFieldType = context.fieldMapper(minimumShouldMatchField);
             if (msmFieldType == null) {
@@ -253,13 +266,13 @@ public final class TermsSetQueryBuilder extends AbstractQueryBuilder<TermsSetQue
                 SearchScript.TERMS_SET_QUERY_CONTEXT);
             Map<String, Object> params = new HashMap<>();
             params.putAll(minimumShouldMatchScript.getParams());
-            params.put("num_terms", queries.size());
+            params.put("num_terms", values.size());
             SearchScript.LeafFactory leafFactory = factory.newFactory(params, context.lookup());
             longValuesSource = new ScriptLongValueSource(minimumShouldMatchScript, leafFactory);
         } else {
             throw new IllegalStateException("No minimum should match has been specified");
         }
-        return new CoveringQuery(queries, longValuesSource);
+        return longValuesSource;
     }
 
     static final class ScriptLongValueSource extends LongValuesSource {

server/src/main/java/org/elasticsearch/index/search/QueryParserHelper.java

@@ -25,6 +25,8 @@ import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.FieldMapper;
 import org.elasticsearch.index.mapper.IpFieldMapper;
 import org.elasticsearch.index.mapper.KeywordFieldMapper;
+import org.elasticsearch.index.mapper.MappedFieldType;
+import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.MetadataFieldMapper;
 import org.elasticsearch.index.mapper.NumberFieldMapper;
@@ -88,10 +90,10 @@ public final class QueryParserHelper {
      * @param mapperService The mapper service where to find the mapping.
      * @param field The field name to search.
      */
-    public static FieldMapper getFieldMapper(MapperService mapperService, String field) {
+    public static Mapper getFieldMapper(MapperService mapperService, String field) {
         DocumentMapper mapper = mapperService.documentMapper();
         if (mapper != null) {
-            FieldMapper fieldMapper = mapper.mappers().getMapper(field);
+            Mapper fieldMapper = mapper.mappers().getMapper(field);
             if (fieldMapper != null) {
                 return fieldMapper;
             }
@@ -167,23 +169,27 @@ public final class QueryParserHelper {
             if (fieldSuffix != null && context.fieldMapper(fieldName + fieldSuffix) != null) {
                 fieldName = fieldName + fieldSuffix;
             }
-            FieldMapper mapper = getFieldMapper(context.getMapperService(), fieldName);
-            if (mapper == null) {
-                // Unmapped fields are not ignored
-                fields.put(fieldOrPattern, weight);
-                continue;
-            }
-            if (acceptMetadataField == false && mapper instanceof MetadataFieldMapper) {
-                // Ignore metadata fields
+
+            MappedFieldType fieldType = context.getMapperService().fullName(fieldName);
+            if (fieldType == null) {
+                // Note that we don't ignore unmapped fields.
+                fields.put(fieldName, weight);
                 continue;
             }
+
             // Ignore fields that are not in the allowed mapper types. Some
             // types do not support term queries, and thus we cannot generate
             // a special query for them.
-            String mappingType = mapper.fieldType().typeName();
+            String mappingType = fieldType.typeName();
             if (acceptAllTypes == false && ALLOWED_QUERY_MAPPER_TYPES.contains(mappingType) == false) {
                 continue;
             }
+
+            // Ignore metadata fields.
+            Mapper mapper = getFieldMapper(context.getMapperService(), fieldName);
+            if (acceptMetadataField == false && mapper instanceof MetadataFieldMapper) {
+                continue;
+            }
             fields.put(fieldName, weight);
         }
         checkForTooManyFields(fields);

server/src/main/java/org/elasticsearch/indices/IndicesModule.java

@@ -36,6 +36,7 @@ import org.elasticsearch.index.mapper.BinaryFieldMapper;
 import org.elasticsearch.index.mapper.BooleanFieldMapper;
 import org.elasticsearch.index.mapper.CompletionFieldMapper;
 import org.elasticsearch.index.mapper.DateFieldMapper;
+import org.elasticsearch.index.mapper.FieldAliasMapper;
 import org.elasticsearch.index.mapper.FieldNamesFieldMapper;
 import org.elasticsearch.index.mapper.GeoPointFieldMapper;
 import org.elasticsearch.index.mapper.GeoShapeFieldMapper;
@@ -129,7 +130,9 @@ public class IndicesModule extends AbstractModule {
         mappers.put(ObjectMapper.CONTENT_TYPE, new ObjectMapper.TypeParser());
         mappers.put(ObjectMapper.NESTED_CONTENT_TYPE, new ObjectMapper.TypeParser());
         mappers.put(CompletionFieldMapper.CONTENT_TYPE, new CompletionFieldMapper.TypeParser());
+        mappers.put(FieldAliasMapper.CONTENT_TYPE, new FieldAliasMapper.TypeParser());
         mappers.put(GeoPointFieldMapper.CONTENT_TYPE, new GeoPointFieldMapper.TypeParser());
+
         if (ShapesAvailability.JTS_AVAILABLE && ShapesAvailability.SPATIAL4J_AVAILABLE) {
             mappers.put(GeoShapeFieldMapper.CONTENT_TYPE, new GeoShapeFieldMapper.TypeParser());
         }

server/src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantTermsAggregatorFactory.java

@@ -85,6 +85,12 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
                                              AggregatorFactories.Builder subFactoriesBuilder,
                                              Map<String, Object> metaData) throws IOException {
         super(name, config, context, parent, subFactoriesBuilder, metaData);
+
+        if (!config.unmapped()) {
+            this.fieldType = config.fieldContext().fieldType();
+            this.indexedFieldName = fieldType.name();
+        }
+
         this.includeExclude = includeExclude;
         this.executionHint = executionHint;
         this.filter = filterBuilder == null
@@ -98,15 +104,6 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
                 : searcher.count(filter);
         this.bucketCountThresholds = bucketCountThresholds;
         this.significanceHeuristic = significanceHeuristic;
-        setFieldInfo(context);
-
-    }
-
-    private void setFieldInfo(SearchContext context) {
-        if (!config.unmapped()) {
-            this.indexedFieldName = config.fieldContext().field();
-            fieldType = context.smartNameFieldType(indexedFieldName);
-        }
     }
 
     /**

server/src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantTextAggregationBuilder.java

@@ -343,13 +343,10 @@ public class SignificantTextAggregationBuilder extends AbstractAggregationBuilde
     protected AggregatorFactory<?> doBuild(SearchContext context, AggregatorFactory<?> parent,
             Builder subFactoriesBuilder) throws IOException {
         SignificanceHeuristic executionHeuristic = this.significanceHeuristic.rewrite(context);
-        String[] execFieldNames = sourceFieldNames;
-        if (execFieldNames == null) {
-            execFieldNames = new String[] { fieldName };
-        }
+
         return new SignificantTextAggregatorFactory(name, includeExclude, filterBuilder,
                 bucketCountThresholds, executionHeuristic, context, parent, subFactoriesBuilder,
-                fieldName, execFieldNames, filterDuplicateText, metaData);
+                fieldName, sourceFieldNames, filterDuplicateText, metaData);
     }
 
     @Override

server/src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantTextAggregatorFactory.java

@@ -71,12 +71,19 @@ public class SignificantTextAggregatorFactory extends AggregatorFactory<Signific
             AggregatorFactories.Builder subFactoriesBuilder, String fieldName, String [] sourceFieldNames,
             boolean filterDuplicateText, Map<String, Object> metaData) throws IOException {
         super(name, context, parent, subFactoriesBuilder, metaData);
+
+        // Note that if the field is unmapped (its field type is null), we don't fail,
+        // and just use the given field name as a placeholder.
+        this.fieldType = context.getQueryShardContext().fieldMapper(fieldName);
+        this.indexedFieldName = fieldType != null ? fieldType.name() : fieldName;
+        this.sourceFieldNames = sourceFieldNames == null
+            ? new String[] { indexedFieldName }
+            : sourceFieldNames;
+
         this.includeExclude = includeExclude;
         this.filter = filterBuilder == null
                 ? null
                 : filterBuilder.toQuery(context.getQueryShardContext());
-        this.indexedFieldName = fieldName;
-        this.sourceFieldNames = sourceFieldNames;
         this.filterDuplicateText = filterDuplicateText;
         IndexSearcher searcher = context.searcher();
         // Important - need to use the doc count that includes deleted docs
@@ -86,11 +93,8 @@ public class SignificantTextAggregatorFactory extends AggregatorFactory<Signific
                 : searcher.count(filter);
         this.bucketCountThresholds = bucketCountThresholds;
         this.significanceHeuristic = significanceHeuristic;
-        fieldType = context.getQueryShardContext().fieldMapper(indexedFieldName);
-
     }
 
-
     /**
      * Get the number of docs in the superset.
      */
@@ -133,13 +137,13 @@ public class SignificantTextAggregatorFactory extends AggregatorFactory<Signific
         }
         return context.searcher().count(query);
     }
-    
+
     public long getBackgroundFrequency(BytesRef termBytes) throws IOException {
         String value = format.format(termBytes).toString();
         return getBackgroundFrequency(value);
-    }    
+    }
+
 
-    
     @Override
     public void close() {
         try {
@@ -154,11 +158,11 @@ public class SignificantTextAggregatorFactory extends AggregatorFactory<Signific
     @Override
     protected Aggregator createInternal(Aggregator parent, boolean collectsFromSingleBucket,
             List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
-            throws IOException {        
+            throws IOException {
         if (collectsFromSingleBucket == false) {
             return asMultiBucketAggregator(this, context, parent);
         }
-        
+
         numberOfAggregatorsCreated++;
         BucketCountThresholds bucketCountThresholds = new BucketCountThresholds(this.bucketCountThresholds);
         if (bucketCountThresholds.getShardSize() == SignificantTextAggregationBuilder.DEFAULT_BUCKET_COUNT_THRESHOLDS.getShardSize()) {
@@ -166,7 +170,7 @@ public class SignificantTextAggregatorFactory extends AggregatorFactory<Signific
             // Use default heuristic to avoid any wrong-ranking caused by
             // distributed counting but request double the usual amount.
             // We typically need more than the number of "top" terms requested
-            // by other aggregations as the significance algorithm is in less 
+            // by other aggregations as the significance algorithm is in less
             // of a position to down-select at shard-level - some of the things
             // we want to find have only one occurrence on each shard and as
             // such are impossible to differentiate from non-significant terms
@@ -177,9 +181,9 @@ public class SignificantTextAggregatorFactory extends AggregatorFactory<Signific
 
 //        TODO - need to check with mapping that this is indeed a text field....
 
-        IncludeExclude.StringFilter incExcFilter = includeExclude == null ? null: 
+        IncludeExclude.StringFilter incExcFilter = includeExclude == null ? null:
             includeExclude.convertToStringFilter(DocValueFormat.RAW);
-        
+
         return new SignificantTextAggregator(name, factories, context, parent, pipelineAggregators, bucketCountThresholds,
                 incExcFilter, significanceHeuristic, this, indexedFieldName, sourceFieldNames, filterDuplicateText, metaData);
 

server/src/main/java/org/elasticsearch/search/fetch/FetchPhase.java

@@ -31,7 +31,6 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.document.DocumentField;
 import org.elasticsearch.common.lucene.search.Queries;
-import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.text.Text;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.common.xcontent.XContentType;
@@ -55,7 +54,7 @@ import org.elasticsearch.search.lookup.SourceLookup;
 import org.elasticsearch.tasks.TaskCancelledException;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -84,8 +83,7 @@ public class FetchPhase implements SearchPhase {
     @Override
     public void execute(SearchContext context) {
         final FieldsVisitor fieldsVisitor;
-        Set<String> fieldNames = null;
-        List<String> fieldNamePatterns = null;
+        Map<String, Set<String>> storedToRequestedFields = new HashMap<>();
         StoredFieldsContext storedFieldsContext = context.storedFieldsContext();
 
         if (storedFieldsContext == null) {
@@ -98,39 +96,36 @@ public class FetchPhase implements SearchPhase {
             // disable stored fields entirely
             fieldsVisitor = null;
         } else {
-            for (String fieldName : context.storedFieldsContext().fieldNames()) {
-                if (fieldName.equals(SourceFieldMapper.NAME)) {
+            for (String fieldNameOrPattern : context.storedFieldsContext().fieldNames()) {
+                if (fieldNameOrPattern.equals(SourceFieldMapper.NAME)) {
                     FetchSourceContext fetchSourceContext = context.hasFetchSourceContext() ? context.fetchSourceContext()
-                            : FetchSourceContext.FETCH_SOURCE;
+                        : FetchSourceContext.FETCH_SOURCE;
                     context.fetchSourceContext(new FetchSourceContext(true, fetchSourceContext.includes(), fetchSourceContext.excludes()));
                     continue;
                 }
-                if (Regex.isSimpleMatchPattern(fieldName)) {
-                    if (fieldNamePatterns == null) {
-                        fieldNamePatterns = new ArrayList<>();
-                    }
-                    fieldNamePatterns.add(fieldName);
-                } else {
+
+                Collection<String> fieldNames = context.mapperService().simpleMatchToFullName(fieldNameOrPattern);
+                for (String fieldName : fieldNames) {
                     MappedFieldType fieldType = context.smartNameFieldType(fieldName);
                     if (fieldType == null) {
                         // Only fail if we know it is a object field, missing paths / fields shouldn't fail.
                         if (context.getObjectMapper(fieldName) != null) {
                             throw new IllegalArgumentException("field [" + fieldName + "] isn't a leaf field");
                         }
+                    } else {
+                        String storedField = fieldType.name();
+                        Set<String> requestedFields = storedToRequestedFields.computeIfAbsent(
+                            storedField, key -> new HashSet<>());
+                        requestedFields.add(fieldName);
                     }
-                    if (fieldNames == null) {
-                        fieldNames = new HashSet<>();
-                    }
-                    fieldNames.add(fieldName);
                 }
             }
             boolean loadSource = context.sourceRequested();
-            if (fieldNames == null && fieldNamePatterns == null) {
+            if (storedToRequestedFields.isEmpty()) {
                 // empty list specified, default to disable _source if no explicit indication
                 fieldsVisitor = new FieldsVisitor(loadSource);
             } else {
-                fieldsVisitor = new CustomFieldsVisitor(fieldNames == null ? Collections.emptySet() : fieldNames,
-                        fieldNamePatterns == null ? Collections.emptyList() : fieldNamePatterns, loadSource);
+                fieldsVisitor = new CustomFieldsVisitor(storedToRequestedFields.keySet(), loadSource);
             }
         }
 
@@ -149,10 +144,11 @@ public class FetchPhase implements SearchPhase {
                 final SearchHit searchHit;
                 int rootDocId = findRootDocumentIfNested(context, subReaderContext, subDocId);
                 if (rootDocId != -1) {
-                    searchHit = createNestedSearchHit(context, docId, subDocId, rootDocId, fieldNames, fieldNamePatterns,
-                            subReaderContext);
+                    searchHit = createNestedSearchHit(context, docId, subDocId, rootDocId,
+                        storedToRequestedFields, subReaderContext);
                 } else {
-                    searchHit = createSearchHit(context, fieldsVisitor, docId, subDocId, subReaderContext);
+                    searchHit = createSearchHit(context, fieldsVisitor, docId, subDocId,
+                        storedToRequestedFields, subReaderContext);
                 }
 
                 hits[index] = searchHit;
@@ -190,21 +186,18 @@ public class FetchPhase implements SearchPhase {
         return -1;
     }
 
-    private SearchHit createSearchHit(SearchContext context, FieldsVisitor fieldsVisitor, int docId, int subDocId,
+    private SearchHit createSearchHit(SearchContext context,
+                                      FieldsVisitor fieldsVisitor,
+                                      int docId,
+                                      int subDocId,
+                                      Map<String, Set<String>> storedToRequestedFields,
                                       LeafReaderContext subReaderContext) {
         if (fieldsVisitor == null) {
             return new SearchHit(docId);
         }
-        loadStoredFields(context, subReaderContext, fieldsVisitor, subDocId);
-        fieldsVisitor.postProcess(context.mapperService());
 
-        Map<String, DocumentField> searchFields = null;
-        if (!fieldsVisitor.fields().isEmpty()) {
-            searchFields = new HashMap<>(fieldsVisitor.fields().size());
-            for (Map.Entry<String, List<Object>> entry : fieldsVisitor.fields().entrySet()) {
-                searchFields.put(entry.getKey(), new DocumentField(entry.getKey(), entry.getValue()));
-            }
-        }
+        Map<String, DocumentField> searchFields = getSearchFields(context, fieldsVisitor, subDocId,
+            storedToRequestedFields, subReaderContext);
 
         DocumentMapper documentMapper = context.mapperService().documentMapper(fieldsVisitor.uid().type());
         Text typeText;
@@ -223,9 +216,40 @@ public class FetchPhase implements SearchPhase {
         return searchHit;
     }
 
-    private SearchHit createNestedSearchHit(SearchContext context, int nestedTopDocId, int nestedSubDocId,
-                                            int rootSubDocId, Set<String> fieldNames,
-                                            List<String> fieldNamePatterns, LeafReaderContext subReaderContext) throws IOException {
+    private Map<String, DocumentField> getSearchFields(SearchContext context,
+                                                       FieldsVisitor fieldsVisitor,
+                                                       int subDocId,
+                                                       Map<String, Set<String>> storedToRequestedFields,
+                                                       LeafReaderContext subReaderContext) {
+        loadStoredFields(context, subReaderContext, fieldsVisitor, subDocId);
+        fieldsVisitor.postProcess(context.mapperService());
+
+        if (fieldsVisitor.fields().isEmpty()) {
+            return null;
+        }
+
+        Map<String, DocumentField> searchFields = new HashMap<>(fieldsVisitor.fields().size());
+        for (Map.Entry<String, List<Object>> entry : fieldsVisitor.fields().entrySet()) {
+            String storedField = entry.getKey();
+            List<Object> storedValues = entry.getValue();
+
+            if (storedToRequestedFields.containsKey(storedField)) {
+                for (String requestedField : storedToRequestedFields.get(storedField)) {
+                    searchFields.put(requestedField, new DocumentField(requestedField, storedValues));
+                }
+            } else {
+                searchFields.put(storedField, new DocumentField(storedField, storedValues));
+            }
+        }
+        return searchFields;
+    }
+
+    private SearchHit createNestedSearchHit(SearchContext context,
+                                            int nestedTopDocId,
+                                            int nestedSubDocId,
+                                            int rootSubDocId,
+                                            Map<String, Set<String>> storedToRequestedFields,
+                                            LeafReaderContext subReaderContext) throws IOException {
         // Also if highlighting is requested on nested documents we need to fetch the _source from the root document,
         // otherwise highlighting will attempt to fetch the _source from the nested doc, which will fail,
         // because the entire _source is only stored with the root document.
@@ -244,9 +268,13 @@ public class FetchPhase implements SearchPhase {
             source = null;
         }
 
+        Map<String, DocumentField> searchFields = null;
+        if (context.hasStoredFields() && !context.storedFieldsContext().fieldNames().isEmpty()) {
+            FieldsVisitor nestedFieldsVisitor = new CustomFieldsVisitor(storedToRequestedFields.keySet(), false);
+            searchFields = getSearchFields(context, nestedFieldsVisitor, nestedSubDocId,
+                storedToRequestedFields, subReaderContext);
+        }
 
-        Map<String, DocumentField> searchFields =
-                getSearchFields(context, nestedSubDocId, fieldNames, fieldNamePatterns, subReaderContext);
         DocumentMapper documentMapper = context.mapperService().documentMapper(uid.type());
         SourceLookup sourceLookup = context.lookup().source();
         sourceLookup.setSegmentAndDocument(subReaderContext, nestedSubDocId);
@@ -307,26 +335,6 @@ public class FetchPhase implements SearchPhase {
         return new SearchHit(nestedTopDocId, uid.id(), documentMapper.typeText(), nestedIdentity, searchFields);
     }
 
-    private Map<String, DocumentField> getSearchFields(SearchContext context, int nestedSubDocId, Set<String> fieldNames,
-                                                       List<String> fieldNamePatterns, LeafReaderContext subReaderContext) {
-        Map<String, DocumentField> searchFields = null;
-        if (context.hasStoredFields() && !context.storedFieldsContext().fieldNames().isEmpty()) {
-            FieldsVisitor nestedFieldsVisitor = new CustomFieldsVisitor(fieldNames == null ? Collections.emptySet() : fieldNames,
-                    fieldNamePatterns == null ? Collections.emptyList() : fieldNamePatterns, false);
-            if (nestedFieldsVisitor != null) {
-                loadStoredFields(context, subReaderContext, nestedFieldsVisitor, nestedSubDocId);
-                nestedFieldsVisitor.postProcess(context.mapperService());
-                if (!nestedFieldsVisitor.fields().isEmpty()) {
-                    searchFields = new HashMap<>(nestedFieldsVisitor.fields().size());
-                    for (Map.Entry<String, List<Object>> entry : nestedFieldsVisitor.fields().entrySet()) {
-                        searchFields.put(entry.getKey(), new DocumentField(entry.getKey(), entry.getValue()));
-                    }
-                }
-            }
-        }
-        return searchFields;
-    }
-
     private SearchHit.NestedIdentity getInternalNestedIdentity(SearchContext context, int nestedSubDocId,
                                                                LeafReaderContext subReaderContext,
                                                                MapperService mapperService,

server/src/main/java/org/elasticsearch/search/fetch/subphase/highlight/HighlightPhase.java

@@ -100,7 +100,7 @@ public class HighlightPhase extends AbstractComponent implements FetchSubPhase {
                 if (highlightQuery == null) {
                     highlightQuery = context.parsedQuery().query();
                 }
-                HighlighterContext highlighterContext = new HighlighterContext(fieldName,
+                HighlighterContext highlighterContext = new HighlighterContext(fieldType.name(),
                     field, fieldType, context, hitContext, highlightQuery);
 
                 if ((highlighter.canHighlight(fieldType) == false) && fieldNameContainsWildcards) {
@@ -109,7 +109,11 @@ public class HighlightPhase extends AbstractComponent implements FetchSubPhase {
                 }
                 HighlightField highlightField = highlighter.highlight(highlighterContext);
                 if (highlightField != null) {
-                    highlightFields.put(highlightField.name(), highlightField);
+                    // Note that we make sure to use the original field name in the response. This is because the
+                    // original field could be an alias, and highlighter implementations may instead reference the
+                    // concrete field it points to.
+                    highlightFields.put(fieldName,
+                        new HighlightField(fieldName, highlightField.fragments()));
                 }
             }
         }

server/src/main/java/org/elasticsearch/search/lookup/LeafFieldsLookup.java

@@ -148,7 +148,7 @@ public class LeafFieldsLookup implements Map {
                 reader.document(docId, fieldVisitor);
                 fieldVisitor.postProcess(mapperService);
                 List<Object> storedFields = fieldVisitor.fields().get(data.fieldType().name());
-                data.fields(singletonMap(name, storedFields));
+                data.fields(singletonMap(fieldName, storedFields));
             } catch (IOException e) {
                 throw new ElasticsearchParseException("failed to load field [{}]", e, name);
             }

server/src/main/java/org/elasticsearch/search/suggest/SuggestionBuilder.java

@@ -27,7 +27,6 @@ import org.elasticsearch.common.io.stream.NamedWriteable;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.lucene.BytesRefs;
-import org.elasticsearch.common.xcontent.ToXContent.Params;
 import org.elasticsearch.common.xcontent.ToXContentFragment;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
@@ -321,7 +320,7 @@ public abstract class SuggestionBuilder<T extends SuggestionBuilder<T>> implemen
             suggestionContext.setAnalyzer(luceneAnalyzer);
         }
 
-        suggestionContext.setField(field);
+        suggestionContext.setField(fieldType.name());
 
         if (size != null) {
             suggestionContext.setSize(size);

server/src/main/java/org/elasticsearch/search/suggest/completion/context/GeoContextMapping.java

@@ -29,8 +29,8 @@ import org.elasticsearch.common.unit.DistanceUnit;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentParser.Token;
-import org.elasticsearch.index.mapper.FieldMapper;
 import org.elasticsearch.index.mapper.GeoPointFieldMapper;
+import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.ParseContext;
 import org.elasticsearch.index.mapper.ParseContext.Document;
 
@@ -138,8 +138,8 @@ public class GeoContextMapping extends ContextMapping<GeoQueryContext> {
     @Override
     public Set<CharSequence> parseContext(ParseContext parseContext, XContentParser parser) throws IOException, ElasticsearchParseException {
         if (fieldName != null) {
-            FieldMapper mapper = parseContext.docMapper().mappers().getMapper(fieldName);
-            if (!(mapper instanceof GeoPointFieldMapper)) {
+            MappedFieldType fieldType = parseContext.mapperService().fullName(fieldName);
+            if (!(fieldType instanceof GeoPointFieldMapper.GeoPointFieldType)) {
                 throw new ElasticsearchParseException("referenced field must be mapped to geo_point");
             }
         }

server/src/test/java/org/elasticsearch/index/analysis/PreBuiltAnalyzerTests.java

@@ -21,12 +21,11 @@ package org.elasticsearch.index.analysis;
 import org.apache.lucene.analysis.Analyzer;
 import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
-import org.elasticsearch.common.Strings;
-import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.MappedFieldType;
+import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.indices.analysis.PreBuiltAnalyzers;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESSingleNodeTestCase;
@@ -84,14 +83,14 @@ public class PreBuiltAnalyzerTests extends ESSingleNodeTestCase {
 
         NamedAnalyzer namedAnalyzer = new PreBuiltAnalyzerProvider(analyzerName, AnalyzerScope.INDEX, randomPreBuiltAnalyzer.getAnalyzer(randomVersion)).get();
 
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
                 .startObject("properties").startObject("field").field("type", "text").field("analyzer", analyzerName).endObject().endObject()
-                .endObject().endObject());
-        DocumentMapper docMapper = createIndex("test", indexSettings).mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
+                .endObject().endObject();
+        MapperService mapperService = createIndex("test", indexSettings, "type", mapping).mapperService();
 
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("field");
-        assertThat(fieldMapper.fieldType().searchAnalyzer(), instanceOf(NamedAnalyzer.class));
-        NamedAnalyzer fieldMapperNamedAnalyzer = fieldMapper.fieldType().searchAnalyzer();
+        MappedFieldType fieldType = mapperService.fullName("field");
+        assertThat(fieldType.searchAnalyzer(), instanceOf(NamedAnalyzer.class));
+        NamedAnalyzer fieldMapperNamedAnalyzer = fieldType.searchAnalyzer();
 
         assertThat(fieldMapperNamedAnalyzer.analyzer(), is(namedAnalyzer.analyzer()));
     }

server/src/test/java/org/elasticsearch/index/mapper/BinaryFieldMapperTests.java

@@ -27,6 +27,8 @@ import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.compress.CompressorFactory;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
@@ -49,32 +51,32 @@ public class BinaryFieldMapperTests extends ESSingleNodeTestCase {
     }
 
     public void testDefaultMapping() throws Exception {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
                 .startObject("properties")
                 .startObject("field")
                 .field("type", "binary")
                 .endObject()
                 .endObject()
-                .endObject().endObject());
+                .endObject().endObject();
 
-        DocumentMapper mapper = createIndex("test").mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
+        MapperService mapperService = createIndex("test", Settings.EMPTY, "type", mapping).mapperService();
+        MappedFieldType fieldType = mapperService.fullName("field");
 
-        FieldMapper fieldMapper = mapper.mappers().getMapper("field");
-        assertThat(fieldMapper, instanceOf(BinaryFieldMapper.class));
-        assertThat(fieldMapper.fieldType().stored(), equalTo(false));
+        assertThat(fieldType, instanceOf(BinaryFieldMapper.BinaryFieldType.class));
+        assertThat(fieldType.stored(), equalTo(false));
     }
 
     public void testStoredValue() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
                 .startObject("properties")
                 .startObject("field")
                 .field("type", "binary")
                 .field("store", true)
                 .endObject()
                 .endObject()
-                .endObject().endObject());
+                .endObject().endObject();
 
-        DocumentMapper mapper = createIndex("test").mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
+        MapperService mapperService = createIndex("test", Settings.EMPTY, "type", mapping).mapperService();
 
         // case 1: a simple binary value
         final byte[] binaryValue1 = new byte[100];
@@ -89,13 +91,14 @@ public class BinaryFieldMapperTests extends ESSingleNodeTestCase {
         assertTrue(CompressorFactory.isCompressed(new BytesArray(binaryValue2)));
 
         for (byte[] value : Arrays.asList(binaryValue1, binaryValue2)) {
-            ParsedDocument doc = mapper.parse(SourceToParse.source("test", "type", "id",
+            ParsedDocument doc = mapperService.documentMapper().parse(SourceToParse.source("test", "type", "id",
                     BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("field", value).endObject()),
                     XContentType.JSON));
             BytesRef indexedValue = doc.rootDoc().getBinaryValue("field");
             assertEquals(new BytesRef(value), indexedValue);
-            FieldMapper fieldMapper = mapper.mappers().getMapper("field");
-            Object originalValue = fieldMapper.fieldType().valueForDisplay(indexedValue);
+
+            MappedFieldType fieldType = mapperService.fullName("field");
+            Object originalValue = fieldType.valueForDisplay(indexedValue);
             assertEquals(new BytesArray(value), originalValue);
         }
     }

server/src/test/java/org/elasticsearch/index/mapper/BooleanFieldMapperTests.java

@@ -52,7 +52,6 @@ import static org.hamcrest.Matchers.containsString;
 public class BooleanFieldMapperTests extends ESSingleNodeTestCase {
     private IndexService indexService;
     private DocumentMapperParser parser;
-    private DocumentMapperParser preEs6Parser;
 
     @Before
     public void setup() {
@@ -101,7 +100,7 @@ public class BooleanFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = parser.parse("type", new CompressedXContent(mapping));
-        FieldMapper mapper = defaultMapper.mappers().getMapper("field");
+        Mapper mapper = defaultMapper.mappers().getMapper("field");
         XContentBuilder builder = XContentFactory.jsonBuilder().startObject();
         mapper.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();

server/src/test/java/org/elasticsearch/index/mapper/CompletionFieldMapperTests.java

@@ -32,6 +32,7 @@ import org.apache.lucene.util.automaton.RegExp;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.compress.CompressedXContent;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.Fuzziness;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -61,10 +62,9 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
 
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
         assertThat(fieldMapper, instanceOf(CompletionFieldMapper.class));
-
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        MappedFieldType completionFieldType = ((CompletionFieldMapper) fieldMapper).fieldType();
 
         NamedAnalyzer indexAnalyzer = completionFieldType.indexAnalyzer();
         assertThat(indexAnalyzer.name(), equalTo("simple"));
@@ -94,10 +94,9 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
 
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
         assertThat(fieldMapper, instanceOf(CompletionFieldMapper.class));
-
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        MappedFieldType completionFieldType = ((CompletionFieldMapper) fieldMapper).fieldType();
 
         NamedAnalyzer indexAnalyzer = completionFieldType.indexAnalyzer();
         assertThat(indexAnalyzer.name(), equalTo("simple"));
@@ -129,12 +128,11 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
 
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
         assertThat(fieldMapper, instanceOf(CompletionFieldMapper.class));
 
-        CompletionFieldMapper completionFieldMapper = (CompletionFieldMapper) fieldMapper;
         XContentBuilder builder = jsonBuilder().startObject();
-        completionFieldMapper.toXContent(builder, ToXContent.EMPTY_PARAMS).endObject();
+        fieldMapper.toXContent(builder, ToXContent.EMPTY_PARAMS).endObject();
         builder.close();
         Map<String, Object> serializedMap = createParser(JsonXContent.jsonXContent, BytesReference.bytes(builder)).map();
         Map<String, Object> configMap = (Map<String, Object>) serializedMap.get("completion");
@@ -153,15 +151,15 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+
         ParsedDocument parsedDocument = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
                 .bytes(XContentFactory.jsonBuilder()
                         .startObject()
                         .field("completion", "suggestion")
                         .endObject()),
                 XContentType.JSON));
-        IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertSuggestFields(fields, 1);
     }
 
@@ -192,15 +190,15 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+
         ParsedDocument parsedDocument = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
                 .bytes(XContentFactory.jsonBuilder()
                         .startObject()
                         .array("completion", "suggestion1", "suggestion2")
                         .endObject()),
                 XContentType.JSON));
-        IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertSuggestFields(fields, 2);
     }
 
@@ -212,8 +210,8 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+
         ParsedDocument parsedDocument = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
                 .bytes(XContentFactory.jsonBuilder()
                         .startObject()
@@ -223,7 +221,7 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                         .endObject()
                         .endObject()),
                 XContentType.JSON));
-        IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertSuggestFields(fields, 1);
     }
 
@@ -235,8 +233,8 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+
         ParsedDocument parsedDocument = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
                 .bytes(XContentFactory.jsonBuilder()
                         .startObject()
@@ -246,10 +244,50 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                         .endObject()
                         .endObject()),
                 XContentType.JSON));
-        IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertSuggestFields(fields, 3);
     }
 
+    public void testParsingWithGeoFieldAlias() throws Exception {
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject()
+            .startObject("type1")
+                .startObject("properties")
+                    .startObject("completion")
+                        .field("type", "completion")
+                        .startObject("contexts")
+                            .field("name", "location")
+                            .field("type", "geo")
+                            .field("path", "alias")
+                        .endObject()
+                    .endObject()
+                    .startObject("birth-place")
+                        .field("type", "geo_point")
+                    .endObject()
+                    .startObject("alias")
+                        .field("type", "alias")
+                        .field("path", "birth-place")
+                    .endObject()
+                .endObject()
+            .endObject()
+        .endObject();
+
+        MapperService mapperService = createIndex("test", Settings.EMPTY, "type1", mapping).mapperService();
+        Mapper fieldMapper = mapperService.documentMapper().mappers().getMapper("completion");
+
+        ParsedDocument parsedDocument = mapperService.documentMapper().parse(SourceToParse.source("test", "type1", "1",
+            BytesReference.bytes(XContentFactory.jsonBuilder()
+                .startObject()
+                    .startObject("completion")
+                        .field("input", "suggestion")
+                        .startObject("contexts")
+                            .field("location", "37.77,-122.42")
+                        .endObject()
+                    .endObject()
+                .endObject()), XContentType.JSON));
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
+        assertSuggestFields(fields, 1);
+    }
+
     public void testParsingFull() throws Exception {
         String mapping = Strings.toString(jsonBuilder().startObject().startObject("type1")
                 .startObject("properties").startObject("completion")
@@ -258,8 +296,8 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+
         ParsedDocument parsedDocument = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
                 .bytes(XContentFactory.jsonBuilder()
                         .startObject()
@@ -279,7 +317,7 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                         .endArray()
                         .endObject()),
                 XContentType.JSON));
-        IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertSuggestFields(fields, 3);
     }
 
@@ -291,8 +329,8 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
-        MappedFieldType completionFieldType = fieldMapper.fieldType();
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+
         ParsedDocument parsedDocument = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
                 .bytes(XContentFactory.jsonBuilder()
                         .startObject()
@@ -312,7 +350,7 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                         .endArray()
                         .endObject()),
                 XContentType.JSON));
-        IndexableField[] fields = parsedDocument.rootDoc().getFields(completionFieldType.name());
+        IndexableField[] fields = parsedDocument.rootDoc().getFields(fieldMapper.name());
         assertSuggestFields(fields, 6);
     }
 
@@ -420,7 +458,7 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
         CompletionFieldMapper completionFieldMapper = (CompletionFieldMapper) fieldMapper;
         Query prefixQuery = completionFieldMapper.fieldType().prefixQuery(new BytesRef("co"));
         assertThat(prefixQuery, instanceOf(PrefixCompletionQuery.class));
@@ -434,7 +472,7 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
         CompletionFieldMapper completionFieldMapper = (CompletionFieldMapper) fieldMapper;
         Query prefixQuery = completionFieldMapper.fieldType().fuzzyQuery("co",
                 Fuzziness.fromEdits(FuzzyCompletionQuery.DEFAULT_MAX_EDITS), FuzzyCompletionQuery.DEFAULT_NON_FUZZY_PREFIX,
@@ -451,7 +489,7 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("completion");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("completion");
         CompletionFieldMapper completionFieldMapper = (CompletionFieldMapper) fieldMapper;
         Query prefixQuery = completionFieldMapper.fieldType()
                 .regexpQuery(new BytesRef("co"), RegExp.ALL, Operations.DEFAULT_MAX_DETERMINIZED_STATES);

server/src/test/java/org/elasticsearch/index/mapper/CopyToMapperTests.java

@@ -72,7 +72,7 @@ public class CopyToMapperTests extends ESSingleNodeTestCase {
         IndexService index = createIndex("test");
         client().admin().indices().preparePutMapping("test").setType("type1").setSource(mapping, XContentType.JSON).get();
         DocumentMapper docMapper = index.mapperService().documentMapper("type1");
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("copy_test");
+        Mapper fieldMapper = docMapper.mappers().getMapper("copy_test");
 
         // Check json serialization
         TextFieldMapper stringFieldMapper = (TextFieldMapper) fieldMapper;
@@ -123,7 +123,7 @@ public class CopyToMapperTests extends ESSingleNodeTestCase {
 
         docMapper = index.mapperService().documentMapper("type1");
         fieldMapper = docMapper.mappers().getMapper("new_field");
-        assertThat(fieldMapper.fieldType().typeName(), equalTo("long"));
+        assertThat(fieldMapper.typeName(), equalTo("long"));
     }
 
     public void testCopyToFieldsInnerObjectParsing() throws Exception {
@@ -308,13 +308,15 @@ public class CopyToMapperTests extends ESSingleNodeTestCase {
 
         MapperService mapperService = createIndex("test").mapperService();
         DocumentMapper docMapperBefore = mapperService.merge("type1", new CompressedXContent(mappingBefore), MapperService.MergeReason.MAPPING_UPDATE);
+        FieldMapper fieldMapperBefore = (FieldMapper) docMapperBefore.mappers().getMapper("copy_test");
 
-        assertEquals(Arrays.asList("foo", "bar"), docMapperBefore.mappers().getMapper("copy_test").copyTo().copyToFields());
+        assertEquals(Arrays.asList("foo", "bar"), fieldMapperBefore.copyTo().copyToFields());
 
         DocumentMapper docMapperAfter = mapperService.merge("type1", new CompressedXContent(mappingAfter), MapperService.MergeReason.MAPPING_UPDATE);
+        FieldMapper fieldMapperAfter = (FieldMapper) docMapperAfter.mappers().getMapper("copy_test");
 
-        assertEquals(Arrays.asList("baz", "bar"), docMapperAfter.mappers().getMapper("copy_test").copyTo().copyToFields());
-        assertEquals(Arrays.asList("foo", "bar"), docMapperBefore.mappers().getMapper("copy_test").copyTo().copyToFields());
+        assertEquals(Arrays.asList("baz", "bar"), fieldMapperAfter.copyTo().copyToFields());
+        assertEquals(Arrays.asList("foo", "bar"), fieldMapperBefore.copyTo().copyToFields());
     }
 
     public void testCopyToNestedField() throws Exception {

server/src/test/java/org/elasticsearch/index/mapper/DateFieldMapperTests.java

@@ -382,11 +382,11 @@ public class DateFieldMapperTests extends ESSingleNodeTestCase {
             .startObject("properties")
             .startObject("release_date").field("type", "date").field("format", "yyyy/MM/dd").endObject()
             .endObject().endObject().endObject());
-        DocumentMapper initMapper = indexService.mapperService().merge("movie", new CompressedXContent(initMapping),
+        indexService.mapperService().merge("movie", new CompressedXContent(initMapping),
             MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertThat(initMapper.mappers().getMapper("release_date"), notNullValue());
-        assertFalse(initMapper.mappers().getMapper("release_date").fieldType().stored());
+        assertThat(indexService.mapperService().fullName("release_date"), notNullValue());
+        assertFalse(indexService.mapperService().fullName("release_date").stored());
 
         String updateFormatMapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("movie")
             .startObject("properties")

server/src/test/java/org/elasticsearch/index/mapper/DocumentFieldMapperTests.java

@@ -39,6 +39,7 @@ import org.elasticsearch.index.query.QueryShardContext;
 import java.io.IOException;
 import java.io.StringReader;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 public class DocumentFieldMapperTests extends LuceneTestCase {
@@ -138,7 +139,12 @@ public class DocumentFieldMapperTests extends LuceneTestCase {
         Analyzer defaultSearch = new FakeAnalyzer("default_search");
         Analyzer defaultSearchQuote = new FakeAnalyzer("default_search_quote");
 
-        DocumentFieldMappers documentFieldMappers = new DocumentFieldMappers(Arrays.asList(fieldMapper1, fieldMapper2), defaultIndex, defaultSearch, defaultSearchQuote);
+        DocumentFieldMappers documentFieldMappers = new DocumentFieldMappers(
+            Arrays.asList(fieldMapper1, fieldMapper2),
+            Collections.emptyList(),
+            defaultIndex,
+            defaultSearch,
+            defaultSearchQuote);
 
         assertAnalyzes(documentFieldMappers.indexAnalyzer(), "field1", "index");
         assertAnalyzes(documentFieldMappers.searchAnalyzer(), "field1", "search");

server/src/test/java/org/elasticsearch/index/mapper/DocumentMapperMergeTests.java

@@ -23,9 +23,10 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.compress.CompressedXContent;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentType;
-import org.elasticsearch.index.analysis.NamedAnalyzer;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
 import java.io.IOException;
@@ -104,38 +105,50 @@ public class DocumentMapperMergeTests extends ESSingleNodeTestCase {
     }
 
     public void testMergeSearchAnalyzer() throws Exception {
-        DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
-        String mapping1 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
-                .startObject("properties").startObject("field").field("type", "text").field("analyzer", "standard").field("search_analyzer", "whitespace").endObject().endObject()
-                .endObject().endObject());
+        XContentBuilder mapping1 = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "text")
+                .field("analyzer", "standard")
+                .field("search_analyzer", "whitespace")
+            .endObject().endObject()
+        .endObject().endObject();
+        MapperService mapperService = createIndex("test", Settings.EMPTY, "type", mapping1).mapperService();
+
+        assertThat(mapperService.fullName("field").searchAnalyzer().name(), equalTo("whitespace"));
+
         String mapping2 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
-                .startObject("properties").startObject("field").field("type", "text").field("analyzer", "standard").field("search_analyzer", "keyword").endObject().endObject()
-                .endObject().endObject());
+            .startObject("properties").startObject("field")
+                .field("type", "text")
+                .field("analyzer", "standard")
+                .field("search_analyzer", "keyword")
+            .endObject().endObject()
+        .endObject().endObject());
 
-        DocumentMapper existing = parser.parse("type", new CompressedXContent(mapping1));
-        DocumentMapper changed = parser.parse("type", new CompressedXContent(mapping2));
-
-        assertThat(((NamedAnalyzer) existing.mappers().getMapper("field").fieldType().searchAnalyzer()).name(), equalTo("whitespace"));
-        DocumentMapper merged = existing.merge(changed.mapping());
-
-        assertThat(((NamedAnalyzer) merged.mappers().getMapper("field").fieldType().searchAnalyzer()).name(), equalTo("keyword"));
+        mapperService.merge("type", new CompressedXContent(mapping2), MapperService.MergeReason.MAPPING_UPDATE);
+        assertThat(mapperService.fullName("field").searchAnalyzer().name(), equalTo("keyword"));
     }
 
     public void testChangeSearchAnalyzerToDefault() throws Exception {
-        MapperService mapperService = createIndex("test").mapperService();
-        String mapping1 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
-                .startObject("properties").startObject("field").field("type", "text").field("analyzer", "standard").field("search_analyzer", "whitespace").endObject().endObject()
-                .endObject().endObject());
+          XContentBuilder mapping1 = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "text")
+                .field("analyzer", "standard")
+                .field("search_analyzer", "whitespace")
+            .endObject().endObject()
+        .endObject().endObject();
+        MapperService mapperService = createIndex("test", Settings.EMPTY, "type", mapping1).mapperService();
+
+        assertThat(mapperService.fullName("field").searchAnalyzer().name(), equalTo("whitespace"));
+
         String mapping2 = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
-                .startObject("properties").startObject("field").field("type", "text").field("analyzer", "standard").endObject().endObject()
-                .endObject().endObject());
+            .startObject("properties").startObject("field")
+                .field("type", "text")
+                .field("analyzer", "standard")
+            .endObject().endObject()
+        .endObject().endObject());
 
-        DocumentMapper existing = mapperService.merge("type", new CompressedXContent(mapping1), MapperService.MergeReason.MAPPING_UPDATE);
-        DocumentMapper merged = mapperService.merge("type", new CompressedXContent(mapping2), MapperService.MergeReason.MAPPING_UPDATE);
-
-        assertThat(((NamedAnalyzer) existing.mappers().getMapper("field").fieldType().searchAnalyzer()).name(), equalTo("whitespace"));
-
-        assertThat(((NamedAnalyzer) merged.mappers().getMapper("field").fieldType().searchAnalyzer()).name(), equalTo("standard"));
+        mapperService.merge("type", new CompressedXContent(mapping2), MapperService.MergeReason.MAPPING_UPDATE);
+        assertThat(mapperService.fullName("field").searchAnalyzer().name(), equalTo("standard"));
     }
 
     public void testConcurrentMergeTest() throws Throwable {

server/src/test/java/org/elasticsearch/index/mapper/DocumentParserTests.java

@@ -1001,7 +1001,7 @@ public class DocumentParserTests extends ESSingleNodeTestCase {
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/elasticsearch/index/mapper/simple/test1.json"));
         Document doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
 
-        assertThat(doc.get(docMapper.mappers().getMapper("name.first").fieldType().name()), equalTo("shay"));
+        assertThat(doc.get(docMapper.mappers().getMapper("name.first").name()), equalTo("shay"));
         doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
     }
 
@@ -1014,8 +1014,8 @@ public class DocumentParserTests extends ESSingleNodeTestCase {
         DocumentMapper builtDocMapper = parser.parse("person", new CompressedXContent(builtMapping));
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/elasticsearch/index/mapper/simple/test1.json"));
         Document doc = builtDocMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
-        assertThat(doc.getBinaryValue(docMapper.idFieldMapper().fieldType().name()), equalTo(Uid.encodeId("1")));
-        assertThat(doc.get(docMapper.mappers().getMapper("name.first").fieldType().name()), equalTo("shay"));
+        assertThat(doc.getBinaryValue(docMapper.idFieldMapper().name()), equalTo(Uid.encodeId("1")));
+        assertThat(doc.get(docMapper.mappers().getMapper("name.first").name()), equalTo("shay"));
     }
 
     public void testSimpleParser() throws Exception {
@@ -1026,8 +1026,8 @@ public class DocumentParserTests extends ESSingleNodeTestCase {
 
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/elasticsearch/index/mapper/simple/test1.json"));
         Document doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
-        assertThat(doc.getBinaryValue(docMapper.idFieldMapper().fieldType().name()), equalTo(Uid.encodeId("1")));
-        assertThat(doc.get(docMapper.mappers().getMapper("name.first").fieldType().name()), equalTo("shay"));
+        assertThat(doc.getBinaryValue(docMapper.idFieldMapper().name()), equalTo(Uid.encodeId("1")));
+        assertThat(doc.get(docMapper.mappers().getMapper("name.first").name()), equalTo("shay"));
     }
 
     public void testSimpleParserNoTypeNoId() throws Exception {
@@ -1035,8 +1035,8 @@ public class DocumentParserTests extends ESSingleNodeTestCase {
         DocumentMapper docMapper = createIndex("test").mapperService().documentMapperParser().parse("person", new CompressedXContent(mapping));
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/elasticsearch/index/mapper/simple/test1-notype-noid.json"));
         Document doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
-        assertThat(doc.getBinaryValue(docMapper.idFieldMapper().fieldType().name()), equalTo(Uid.encodeId("1")));
-        assertThat(doc.get(docMapper.mappers().getMapper("name.first").fieldType().name()), equalTo("shay"));
+        assertThat(doc.getBinaryValue(docMapper.idFieldMapper().name()), equalTo(Uid.encodeId("1")));
+        assertThat(doc.get(docMapper.mappers().getMapper("name.first").name()), equalTo("shay"));
     }
 
     public void testAttributes() throws Exception {
@@ -1389,4 +1389,98 @@ public class DocumentParserTests extends ESSingleNodeTestCase {
                 client().prepareIndex("idx", "type").setSource(bytes2, XContentType.JSON).get());
         assertThat(ExceptionsHelper.detailedMessage(err), containsString("field name cannot be an empty string"));
     }
+
+    public void testWriteToFieldAlias() throws Exception {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "concrete-field")
+                        .endObject()
+                        .startObject("concrete-field")
+                            .field("type", "keyword")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+
+        DocumentMapperParser mapperParser = createIndex("test").mapperService().documentMapperParser();
+        DocumentMapper mapper = mapperParser.parse("type", new CompressedXContent(mapping));
+
+        BytesReference bytes = BytesReference.bytes(XContentFactory.jsonBuilder()
+            .startObject()
+                .field("alias-field", "value")
+            .endObject());
+        MapperParsingException exception = expectThrows(MapperParsingException.class,
+            () -> mapper.parse(SourceToParse.source("test", "type", "1", bytes, XContentType.JSON)));
+
+        assertEquals("Cannot write to a field alias [alias-field].", exception.getCause().getMessage());
+    }
+
+     public void testCopyToFieldAlias() throws Exception {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "concrete-field")
+                        .endObject()
+                        .startObject("concrete-field")
+                            .field("type", "keyword")
+                        .endObject()
+                        .startObject("text-field")
+                            .field("type", "text")
+                            .field("copy_to", "alias-field")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+
+        DocumentMapperParser mapperParser = createIndex("test").mapperService().documentMapperParser();
+        DocumentMapper mapper = mapperParser.parse("type", new CompressedXContent(mapping));
+
+        BytesReference bytes = BytesReference.bytes(XContentFactory.jsonBuilder()
+            .startObject()
+                .field("text-field", "value")
+            .endObject());
+        MapperParsingException exception = expectThrows(MapperParsingException.class,
+            () -> mapper.parse(SourceToParse.source("test", "type", "1", bytes, XContentType.JSON)));
+
+        assertEquals("Cannot copy to a field alias [alias-field].", exception.getCause().getMessage());
+    }
+
+    public void testDynamicDottedFieldNameWithFieldAlias() throws Exception {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "concrete-field")
+                        .endObject()
+                        .startObject("concrete-field")
+                            .field("type", "keyword")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+
+        DocumentMapperParser mapperParser = createIndex("test").mapperService().documentMapperParser();
+        DocumentMapper mapper = mapperParser.parse("type", new CompressedXContent(mapping));
+
+        BytesReference bytes = BytesReference.bytes(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("alias-field.dynamic-field")
+                    .field("type", "keyword")
+                .endObject()
+            .endObject());
+        MapperParsingException exception = expectThrows(MapperParsingException.class,
+            () -> mapper.parse(SourceToParse.source("test", "type", "1", bytes, XContentType.JSON)));
+
+        assertEquals("Could not dynamically add mapping for field [alias-field.dynamic-field]. "
+            + "Existing mapping for [alias-field] must be of type object but found [alias].", exception.getMessage());
+    }
 }

server/src/test/java/org/elasticsearch/index/mapper/DoubleIndexingDocTests.java

@@ -45,7 +45,9 @@ public class DoubleIndexingDocTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
         IndexService index = createIndex("test");
         client().admin().indices().preparePutMapping("test").setType("type").setSource(mapping, XContentType.JSON).get();
-        DocumentMapper mapper = index.mapperService().documentMapper("type");
+        MapperService mapperService = index.mapperService();
+        DocumentMapper mapper = mapperService.documentMapper();
+
         QueryShardContext context = index.newQueryShardContext(0, null, () -> 0L, null);
 
         ParsedDocument doc = mapper.parse(SourceToParse.source("test", "type", "1", BytesReference
@@ -61,7 +63,6 @@ public class DoubleIndexingDocTests extends ESSingleNodeTestCase {
         assertNotNull(doc.dynamicMappingsUpdate());
         client().admin().indices().preparePutMapping("test").setType("type")
             .setSource(doc.dynamicMappingsUpdate().toString(), XContentType.JSON).get();
-        mapper = index.mapperService().documentMapper("type");
 
         writer.addDocument(doc.rootDoc());
         writer.addDocument(doc.rootDoc());
@@ -69,25 +70,25 @@ public class DoubleIndexingDocTests extends ESSingleNodeTestCase {
         IndexReader reader = DirectoryReader.open(writer);
         IndexSearcher searcher = new IndexSearcher(reader);
 
-        TopDocs topDocs = searcher.search(mapper.mappers().getMapper("field1").fieldType().termQuery("value1", context), 10);
+        TopDocs topDocs = searcher.search(mapperService.fullName("field1").termQuery("value1", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
 
-        topDocs = searcher.search(mapper.mappers().getMapper("field2").fieldType().termQuery("1", context), 10);
+        topDocs = searcher.search(mapperService.fullName("field2").termQuery("1", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
 
-        topDocs = searcher.search(mapper.mappers().getMapper("field3").fieldType().termQuery("1.1", context), 10);
+        topDocs = searcher.search(mapperService.fullName("field3").termQuery("1.1", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
 
-        topDocs = searcher.search(mapper.mappers().getMapper("field4").fieldType().termQuery("2010-01-01", context), 10);
+        topDocs = searcher.search(mapperService.fullName("field4").termQuery("2010-01-01", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
 
-        topDocs = searcher.search(mapper.mappers().getMapper("field5").fieldType().termQuery("1", context), 10);
+        topDocs = searcher.search(mapperService.fullName("field5").termQuery("1", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
 
-        topDocs = searcher.search(mapper.mappers().getMapper("field5").fieldType().termQuery("2", context), 10);
+        topDocs = searcher.search(mapperService.fullName("field5").termQuery("2", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
 
-        topDocs = searcher.search(mapper.mappers().getMapper("field5").fieldType().termQuery("3", context), 10);
+        topDocs = searcher.search(mapperService.fullName("field5").termQuery("3", context), 10);
         assertThat(topDocs.totalHits, equalTo(2L));
         writer.close();
         reader.close();

server/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java

@@ -625,11 +625,11 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
             .setSource(doc.dynamicMappingsUpdate().toString(), XContentType.JSON).get();
 
         defaultMapper = index.mapperService().documentMapper("type");
-        FieldMapper mapper = defaultMapper.mappers().getMapper("s_long");
-        assertThat(mapper.fieldType().typeName(), equalTo("long"));
+        Mapper mapper = defaultMapper.mappers().getMapper("s_long");
+        assertThat(mapper.typeName(), equalTo("long"));
 
         mapper = defaultMapper.mappers().getMapper("s_double");
-        assertThat(mapper.fieldType().typeName(), equalTo("float"));
+        assertThat(mapper.typeName(), equalTo("float"));
     }
 
     public void testNumericDetectionDefault() throws Exception {
@@ -652,7 +652,7 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
             .setSource(doc.dynamicMappingsUpdate().toString(), XContentType.JSON).get());
 
         defaultMapper = index.mapperService().documentMapper("type");
-        FieldMapper mapper = defaultMapper.mappers().getMapper("s_long");
+        Mapper mapper = defaultMapper.mappers().getMapper("s_long");
         assertThat(mapper, instanceOf(TextFieldMapper.class));
 
         mapper = defaultMapper.mappers().getMapper("s_double");

server/src/test/java/org/elasticsearch/index/mapper/DynamicTemplatesTests.java

@@ -30,11 +30,11 @@ import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.mapper.ParseContext.Document;
 import org.elasticsearch.test.ESSingleNodeTestCase;
-import org.hamcrest.Matchers;
 
 import static org.elasticsearch.test.StreamsUtils.copyToBytesFromClasspath;
 import static org.elasticsearch.test.StreamsUtils.copyToStringFromClasspath;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.notNullValue;
 
 public class DynamicTemplatesTests extends ESSingleNodeTestCase {
     public void testMatchTypeOnly() throws Exception {
@@ -45,7 +45,9 @@ public class DynamicTemplatesTests extends ESSingleNodeTestCase {
                 .endObject().endObject().endArray().endObject().endObject();
         IndexService index = createIndex("test");
         client().admin().indices().preparePutMapping("test").setType("person").setSource(builder).get();
-        DocumentMapper docMapper = index.mapperService().documentMapper("person");
+
+        MapperService mapperService = index.mapperService();
+        DocumentMapper docMapper = mapperService.documentMapper("person");
         builder = JsonXContent.contentBuilder();
         builder.startObject().field("s", "hello").field("l", 1).endObject();
         ParsedDocument parsedDoc = docMapper.parse(SourceToParse.source("test", "person", "1", BytesReference.bytes(builder),
@@ -53,14 +55,11 @@ public class DynamicTemplatesTests extends ESSingleNodeTestCase {
         client().admin().indices().preparePutMapping("test").setType("person")
             .setSource(parsedDoc.dynamicMappingsUpdate().toString(), XContentType.JSON).get();
 
-        docMapper = index.mapperService().documentMapper("person");
-        DocumentFieldMappers mappers = docMapper.mappers();
+        assertThat(mapperService.fullName("s"), notNullValue());
+        assertEquals(IndexOptions.NONE, mapperService.fullName("s").indexOptions());
 
-        assertThat(mappers.getMapper("s"), Matchers.notNullValue());
-        assertEquals(IndexOptions.NONE, mappers.getMapper("s").fieldType().indexOptions());
-
-        assertThat(mappers.getMapper("l"), Matchers.notNullValue());
-        assertNotSame(IndexOptions.NONE, mappers.getMapper("l").fieldType().indexOptions());
+        assertThat(mapperService.fullName("l"), notNullValue());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("l").indexOptions());
 
 
     }
@@ -84,7 +83,7 @@ public class DynamicTemplatesTests extends ESSingleNodeTestCase {
         assertNotSame(IndexOptions.NONE, f.fieldType().indexOptions());
         assertThat(f.fieldType().tokenized(), equalTo(false));
 
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("name");
+        Mapper fieldMapper = docMapper.mappers().getMapper("name");
         assertNotNull(fieldMapper);
 
         f = doc.getField("multi1");
@@ -143,7 +142,7 @@ public class DynamicTemplatesTests extends ESSingleNodeTestCase {
         assertNotSame(IndexOptions.NONE, f.fieldType().indexOptions());
         assertThat(f.fieldType().tokenized(), equalTo(false));
 
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("name");
+        Mapper fieldMapper = docMapper.mappers().getMapper("name");
         assertNotNull(fieldMapper);
 
         f = doc.getField("multi1");

server/src/test/java/org/elasticsearch/index/mapper/FieldAliasMapperTests.java

@@ -0,0 +1,167 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.index.mapper;
+
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.compress.CompressedXContent;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.index.IndexService;
+import org.elasticsearch.index.mapper.MapperService.MergeReason;
+import org.elasticsearch.test.ESSingleNodeTestCase;
+import org.junit.Before;
+
+import java.io.IOException;
+
+public class FieldAliasMapperTests extends ESSingleNodeTestCase {
+    private MapperService mapperService;
+    private DocumentMapperParser parser;
+
+    @Before
+    public void setup() {
+        IndexService indexService = createIndex("test");
+        mapperService = indexService.mapperService();
+        parser = mapperService.documentMapperParser();
+    }
+
+    public void testParsing() throws IOException {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "concrete-field")
+                        .endObject()
+                        .startObject("concrete-field")
+                            .field("type", "keyword")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
+        assertEquals(mapping, mapper.mappingSource().toString());
+    }
+
+    public void testParsingWithMissingPath() throws IOException {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        MapperParsingException exception = expectThrows(MapperParsingException.class,
+            () -> parser.parse("type", new CompressedXContent(mapping)));
+        assertEquals("The [path] property must be specified for field [alias-field].", exception.getMessage());
+    }
+
+    public void testParsingWithExtraArgument() throws IOException {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+            .startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "concrete-field")
+                            .field("extra-field", "extra-value")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        MapperParsingException exception = expectThrows(MapperParsingException.class,
+            () -> parser.parse("type", new CompressedXContent(mapping)));
+        assertEquals("Mapping definition for [alias-field] has unsupported parameters:  [extra-field : extra-value]",
+            exception.getMessage());
+    }
+
+    public void testMerge() throws IOException {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("first-field")
+                            .field("type", "keyword")
+                        .endObject()
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "first-field")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        mapperService.merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
+
+        MappedFieldType firstFieldType = mapperService.fullName("alias-field");
+        assertEquals("first-field", firstFieldType.name());
+        assertTrue(firstFieldType instanceof KeywordFieldMapper.KeywordFieldType);
+
+        String newMapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+               .startObject("type")
+                    .startObject("properties")
+                        .startObject("second-field")
+                            .field("type", "text")
+                        .endObject()
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "second-field")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        mapperService.merge("type", new CompressedXContent(newMapping), MergeReason.MAPPING_UPDATE);
+
+        MappedFieldType secondFieldType = mapperService.fullName("alias-field");
+        assertEquals("second-field", secondFieldType.name());
+        assertTrue(secondFieldType instanceof TextFieldMapper.TextFieldType);
+    }
+
+    public void testMergeFailure() throws IOException {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+                .startObject("type")
+                    .startObject("properties")
+                        .startObject("concrete-field")
+                            .field("type", "text")
+                        .endObject()
+                        .startObject("alias-field")
+                            .field("type", "alias")
+                            .field("path", "concrete-field")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        mapperService.merge("type", new CompressedXContent(mapping), MergeReason.MAPPING_UPDATE);
+
+        String newMapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+               .startObject("type")
+                    .startObject("properties")
+                        .startObject("alias-field")
+                            .field("type", "keyword")
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject());
+        IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
+            () -> mapperService.merge("type", new CompressedXContent(newMapping), MergeReason.MAPPING_UPDATE));
+        assertEquals("Cannot merge a field alias mapping [alias-field] with a mapping that is not for a field alias.",
+            exception.getMessage());
+    }
+}

server/src/test/java/org/elasticsearch/index/mapper/FieldTypeLookupTests.java

@@ -28,10 +28,11 @@ import org.elasticsearch.test.ESTestCase;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
+import static java.util.Collections.emptyList;
+
 public class FieldTypeLookupTests extends ESTestCase {
 
     public void testEmpty() {
@@ -48,7 +49,7 @@ public class FieldTypeLookupTests extends ESTestCase {
     public void testDefaultMapping() {
         FieldTypeLookup lookup = new FieldTypeLookup();
         try {
-            lookup.copyAndAddAll(MapperService.DEFAULT_MAPPING, Collections.emptyList());
+            lookup.copyAndAddAll(MapperService.DEFAULT_MAPPING, emptyList(), emptyList());
             fail();
         } catch (IllegalArgumentException expected) {
             assertEquals("Default mappings should not be added to the lookup", expected.getMessage());
@@ -58,7 +59,7 @@ public class FieldTypeLookupTests extends ESTestCase {
     public void testAddNewField() {
         FieldTypeLookup lookup = new FieldTypeLookup();
         MockFieldMapper f = new MockFieldMapper("foo");
-        FieldTypeLookup lookup2 = lookup.copyAndAddAll("type", newList(f));
+        FieldTypeLookup lookup2 = lookup.copyAndAddAll("type", newList(f), emptyList());
         assertNull(lookup.get("foo"));
         assertNull(lookup.get("bar"));
         assertEquals(f.fieldType(), lookup2.get("foo"));
@@ -70,68 +71,203 @@ public class FieldTypeLookupTests extends ESTestCase {
         MockFieldMapper f = new MockFieldMapper("foo");
         MockFieldMapper f2 = new MockFieldMapper("foo");
         FieldTypeLookup lookup = new FieldTypeLookup();
-        lookup = lookup.copyAndAddAll("type1", newList(f));
-        FieldTypeLookup lookup2 = lookup.copyAndAddAll("type2", newList(f2));
+        lookup = lookup.copyAndAddAll("type1", newList(f), emptyList());
+        FieldTypeLookup lookup2 = lookup.copyAndAddAll("type2", newList(f2), emptyList());
 
         assertEquals(1, size(lookup2.iterator()));
         assertSame(f.fieldType(), lookup2.get("foo"));
         assertEquals(f2.fieldType(), lookup2.get("foo"));
     }
 
-    public void testCheckCompatibilityMismatchedTypes() {
+    public void testMismatchedFieldTypes() {
         FieldMapper f1 = new MockFieldMapper("foo");
         FieldTypeLookup lookup = new FieldTypeLookup();
-        lookup = lookup.copyAndAddAll("type", newList(f1));
+        lookup = lookup.copyAndAddAll("type", newList(f1), emptyList());
 
         OtherFakeFieldType ft2 = new OtherFakeFieldType();
         ft2.setName("foo");
         FieldMapper f2 = new MockFieldMapper("foo", ft2);
         try {
-            lookup.copyAndAddAll("type2", newList(f2));
+            lookup.copyAndAddAll("type2", newList(f2), emptyList());
             fail("expected type mismatch");
         } catch (IllegalArgumentException e) {
             assertTrue(e.getMessage().contains("cannot be changed from type [faketype] to [otherfaketype]"));
         }
     }
 
-    public void testCheckCompatibilityConflict() {
+    public void testConflictingFieldTypes() {
         FieldMapper f1 = new MockFieldMapper("foo");
         FieldTypeLookup lookup = new FieldTypeLookup();
-        lookup = lookup.copyAndAddAll("type", newList(f1));
+        lookup = lookup.copyAndAddAll("type", newList(f1), emptyList());
 
         MappedFieldType ft2 = new MockFieldMapper.FakeFieldType();
         ft2.setName("foo");
         ft2.setBoost(2.0f);
         FieldMapper f2 = new MockFieldMapper("foo", ft2);
-        lookup.copyAndAddAll("type", newList(f2)); // boost is updateable, so ok since we are implicitly updating all types
-        lookup.copyAndAddAll("type2", newList(f2)); // boost is updateable, so ok if forcing
+        lookup.copyAndAddAll("type", newList(f2), emptyList()); // boost is updateable, so ok since we are implicitly updating all types
+        lookup.copyAndAddAll("type2", newList(f2), emptyList()); // boost is updateable, so ok if forcing
         // now with a non changeable setting
         MappedFieldType ft3 = new MockFieldMapper.FakeFieldType();
         ft3.setName("foo");
         ft3.setStored(true);
         FieldMapper f3 = new MockFieldMapper("foo", ft3);
         try {
-            lookup.copyAndAddAll("type2", newList(f3));
+            lookup.copyAndAddAll("type2", newList(f3), emptyList());
             fail("expected conflict");
         } catch (IllegalArgumentException e) {
             assertTrue(e.getMessage().contains("has different [store] values"));
         }
     }
 
-    public void testSimpleMatchFullNames() {
-        MockFieldMapper f1 = new MockFieldMapper("foo");
-        MockFieldMapper f2 = new MockFieldMapper("bar");
+    public void testAddFieldAlias() {
+        MockFieldMapper field = new MockFieldMapper("foo");
+        FieldAliasMapper alias = new FieldAliasMapper("alias", "alias", "foo");
+
         FieldTypeLookup lookup = new FieldTypeLookup();
-        lookup = lookup.copyAndAddAll("type", newList(f1, f2));
+        lookup = lookup.copyAndAddAll("type", newList(field), newList(alias));
+
+        MappedFieldType aliasType = lookup.get("alias");
+        assertEquals(field.fieldType(), aliasType);
+    }
+
+    public void testUpdateFieldAlias() {
+        // Add an alias 'alias' to the concrete field 'foo'.
+        MockFieldMapper.FakeFieldType fieldType1 = new MockFieldMapper.FakeFieldType();
+        MockFieldMapper field1 = new MockFieldMapper("foo", fieldType1);
+        FieldAliasMapper alias1 = new FieldAliasMapper("alias", "alias", "foo");
+
+        FieldTypeLookup lookup = new FieldTypeLookup();
+        lookup = lookup.copyAndAddAll("type", newList(field1), newList(alias1));
+
+        // Check that the alias refers to 'foo'.
+        MappedFieldType aliasType1 = lookup.get("alias");
+        assertEquals(fieldType1, aliasType1);
+
+        // Update the alias to refer to a new concrete field 'bar'.
+        MockFieldMapper.FakeFieldType fieldType2 = new MockFieldMapper.FakeFieldType();
+        fieldType2.setStored(!fieldType1.stored());
+        MockFieldMapper field2 = new MockFieldMapper("bar", fieldType2);
+
+        FieldAliasMapper alias2 = new FieldAliasMapper("alias", "alias", "bar");
+        lookup = lookup.copyAndAddAll("type", newList(field2), newList(alias2));
+
+        // Check that the alias now refers to 'bar'.
+        MappedFieldType aliasType2 = lookup.get("alias");
+        assertEquals(fieldType2, aliasType2);
+    }
+
+    public void testUpdateConcreteFieldWithAlias() {
+        // Add an alias 'alias' to the concrete field 'foo'.
+        FieldAliasMapper alias1 = new FieldAliasMapper("alias", "alias", "foo");
+        MockFieldMapper.FakeFieldType fieldType1 = new MockFieldMapper.FakeFieldType();
+        fieldType1.setBoost(1.0f);
+        MockFieldMapper field1 = new MockFieldMapper("foo", fieldType1);
+
+        FieldTypeLookup lookup = new FieldTypeLookup();
+        lookup = lookup.copyAndAddAll("type", newList(field1), newList(alias1));
+
+        // Check that the alias maps to this field type.
+        MappedFieldType aliasType1 = lookup.get("alias");
+        assertEquals(fieldType1, aliasType1);
+
+        // Update the boost for field 'foo'.
+        MockFieldMapper.FakeFieldType fieldType2 = new MockFieldMapper.FakeFieldType();
+        fieldType2.setBoost(2.0f);
+        MockFieldMapper field2 = new MockFieldMapper("foo", fieldType2);
+        lookup = lookup.copyAndAddAll("type", newList(field2), emptyList());
+
+        // Check that the alias maps to the new field type.
+        MappedFieldType aliasType2 = lookup.get("alias");
+        assertEquals(fieldType2, aliasType2);
+    }
+
+    public void testAliasThatRefersToAlias() {
+        MockFieldMapper field = new MockFieldMapper("foo");
+        FieldAliasMapper alias = new FieldAliasMapper("alias", "alias", "foo");
+        FieldTypeLookup lookup = new FieldTypeLookup()
+            .copyAndAddAll("type", newList(field), newList(alias));
+
+        FieldAliasMapper invalidAlias = new FieldAliasMapper("invalid-alias", "invalid-alias", "alias");
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+            () -> lookup.copyAndAddAll("type", emptyList(), newList(invalidAlias)));
+        assertEquals("Invalid [path] value [alias] for field alias [invalid-alias]: an alias" +
+            " cannot refer to another alias.", e.getMessage());
+    }
+
+    public void testAliasThatRefersToItself() {
+        FieldAliasMapper invalidAlias = new FieldAliasMapper("invalid-alias", "invalid-alias", "invalid-alias");
+
+        FieldTypeLookup lookup = new FieldTypeLookup();
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+            () -> lookup.copyAndAddAll("type", emptyList(), newList(invalidAlias)));
+        assertEquals("Invalid [path] value [invalid-alias] for field alias [invalid-alias]: an alias" +
+            " cannot refer to itself.", e.getMessage());
+    }
+
+    public void testAliasWithNonExistentPath() {
+        FieldAliasMapper invalidAlias = new FieldAliasMapper("invalid-alias", "invalid-alias", "non-existent");
+
+        FieldTypeLookup lookup = new FieldTypeLookup();
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+            () -> lookup.copyAndAddAll("type", emptyList(), newList(invalidAlias)));
+        assertEquals("Invalid [path] value [non-existent] for field alias [invalid-alias]: an alias" +
+            " must refer to an existing field in the mappings.", e.getMessage());
+    }
+
+    public void testAddAliasWithPreexistingField() {
+        MockFieldMapper field = new MockFieldMapper("field");
+        FieldTypeLookup lookup = new FieldTypeLookup()
+            .copyAndAddAll("type", newList(field), emptyList());
+
+        MockFieldMapper invalidField = new MockFieldMapper("invalid");
+        FieldAliasMapper invalidAlias = new FieldAliasMapper("invalid", "invalid", "field");
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+            () -> lookup.copyAndAddAll("type", newList(invalidField), newList(invalidAlias)));
+        assertEquals("The name for field alias [invalid] has already been used to define a concrete field.",
+            e.getMessage());
+    }
+
+    public void testAddFieldWithPreexistingAlias() {
+        MockFieldMapper field = new MockFieldMapper("field");
+        FieldAliasMapper invalidAlias = new FieldAliasMapper("invalid", "invalid", "field");
+
+        FieldTypeLookup lookup = new FieldTypeLookup()
+            .copyAndAddAll("type", newList(field), newList(invalidAlias));
+
+        MockFieldMapper invalidField = new MockFieldMapper("invalid");
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+            () -> lookup.copyAndAddAll("type", newList(invalidField), emptyList()));
+        assertEquals("The name for field [invalid] has already been used to define a field alias.",
+            e.getMessage());
+    }
+
+    public void testSimpleMatchToFullName() {
+        MockFieldMapper field1 = new MockFieldMapper("foo");
+        MockFieldMapper field2 = new MockFieldMapper("bar");
+
+        FieldAliasMapper alias1 = new FieldAliasMapper("food", "food", "foo");
+        FieldAliasMapper alias2 = new FieldAliasMapper("barometer", "barometer", "bar");
+
+        FieldTypeLookup lookup = new FieldTypeLookup();
+        lookup = lookup.copyAndAddAll("type",
+            newList(field1, field2),
+            newList(alias1, alias2));
+
         Collection<String> names = lookup.simpleMatchToFullName("b*");
+
         assertFalse(names.contains("foo"));
+        assertFalse(names.contains("food"));
+
         assertTrue(names.contains("bar"));
+        assertTrue(names.contains("barometer"));
     }
 
     public void testIteratorImmutable() {
         MockFieldMapper f1 = new MockFieldMapper("foo");
         FieldTypeLookup lookup = new FieldTypeLookup();
-        lookup = lookup.copyAndAddAll("type", newList(f1));
+        lookup = lookup.copyAndAddAll("type", newList(f1), emptyList());
 
         try {
             Iterator<MappedFieldType> itr = lookup.iterator();
@@ -144,7 +280,11 @@ public class FieldTypeLookupTests extends ESTestCase {
         }
     }
 
-    static List<FieldMapper> newList(FieldMapper... mapper) {
+    private static List<FieldMapper> newList(FieldMapper... mapper) {
+        return Arrays.asList(mapper);
+    }
+
+    private static List<FieldAliasMapper> newList(FieldAliasMapper... mapper) {
         return Arrays.asList(mapper);
     }
 

server/src/test/java/org/elasticsearch/index/mapper/GenericStoreDynamicTemplateTests.java

@@ -23,10 +23,7 @@ import org.apache.lucene.index.IndexableField;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
-import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.FieldMapper;
 import org.elasticsearch.index.mapper.ParseContext.Document;
-import org.elasticsearch.index.mapper.ParsedDocument;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
 import static org.elasticsearch.test.StreamsUtils.copyToBytesFromClasspath;
@@ -38,13 +35,14 @@ public class GenericStoreDynamicTemplateTests extends ESSingleNodeTestCase {
         String mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/dynamictemplate/genericstore/test-mapping.json");
         IndexService index = createIndex("test");
         client().admin().indices().preparePutMapping("test").setType("person").setSource(mapping, XContentType.JSON).get();
-        DocumentMapper docMapper = index.mapperService().documentMapper("person");
+
+        MapperService mapperService = index.mapperService();
+
         byte[] json = copyToBytesFromClasspath("/org/elasticsearch/index/mapper/dynamictemplate/genericstore/test-data.json");
-        ParsedDocument parsedDoc = docMapper.parse(SourceToParse.source("test", "person", "1", new BytesArray(json),
-                XContentType.JSON));
+        ParsedDocument parsedDoc = mapperService.documentMapper().parse(
+            SourceToParse.source("test", "person", "1", new BytesArray(json), XContentType.JSON));
         client().admin().indices().preparePutMapping("test").setType("person")
             .setSource(parsedDoc.dynamicMappingsUpdate().toString(), XContentType.JSON).get();
-        docMapper = index.mapperService().documentMapper("person");
         Document doc = parsedDoc.rootDoc();
 
         IndexableField f = doc.getField("name");
@@ -52,8 +50,8 @@ public class GenericStoreDynamicTemplateTests extends ESSingleNodeTestCase {
         assertThat(f.stringValue(), equalTo("some name"));
         assertThat(f.fieldType().stored(), equalTo(true));
 
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("name");
-        assertThat(fieldMapper.fieldType().stored(), equalTo(true));
+        MappedFieldType fieldType = mapperService.fullName("name");
+        assertThat(fieldType.stored(), equalTo(true));
 
         boolean stored = false;
         for (IndexableField field : doc.getFields("age")) {
@@ -61,7 +59,7 @@ public class GenericStoreDynamicTemplateTests extends ESSingleNodeTestCase {
         }
         assertTrue(stored);
 
-        fieldMapper = docMapper.mappers().getMapper("age");
-        assertThat(fieldMapper.fieldType().stored(), equalTo(true));
+        fieldType = mapperService.fullName("age");
+        assertThat(fieldType.stored(), equalTo(true));
     }
 }

server/src/test/java/org/elasticsearch/index/mapper/GeoPointFieldMapperTests.java

@@ -287,7 +287,7 @@ public class GeoPointFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser()
             .parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoPointFieldMapper.class));
 
         boolean ignoreZValue = ((GeoPointFieldMapper)fieldMapper).ignoreZValue().value();
@@ -364,10 +364,10 @@ public class GeoPointFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser()
             .parse("type", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoPointFieldMapper.class));
 
-        Object nullValue = fieldMapper.fieldType().nullValue();
+        Object nullValue = ((GeoPointFieldMapper) fieldMapper).fieldType().nullValue();
         assertThat(nullValue, equalTo(new GeoPoint(1, 2)));
 
         ParsedDocument doc = defaultMapper.parse(SourceToParse.source("test", "type", "1", BytesReference

server/src/test/java/org/elasticsearch/index/mapper/GeoShapeFieldMapperTests.java

@@ -59,7 +59,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -83,7 +83,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         ShapeBuilder.Orientation orientation = ((GeoShapeFieldMapper)fieldMapper).fieldType().orientation();
@@ -121,7 +121,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         boolean coerce = ((GeoShapeFieldMapper)fieldMapper).coerce().value();
@@ -157,7 +157,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser()
             .parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         boolean ignoreZValue = ((GeoShapeFieldMapper)fieldMapper).ignoreZValue().value();
@@ -191,7 +191,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
             .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         Explicit<Boolean> ignoreMalformed = ((GeoShapeFieldMapper)fieldMapper).ignoreMalformed();
@@ -225,7 +225,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -248,7 +248,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -276,7 +276,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
 
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -300,7 +300,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
 
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -326,7 +326,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                     .endObject().endObject());
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -350,7 +350,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                     .endObject().endObject());
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -373,7 +373,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                     .endObject().endObject());
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -395,7 +395,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -418,7 +418,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
 
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -440,7 +440,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
                     .endObject().endObject());
 
             DocumentMapper defaultMapper = parser.parse("type1", new CompressedXContent(mapping));
-            FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+            Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
             assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
             GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -475,7 +475,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
         }
 
         // verify nothing changed
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("shape");
+        Mapper fieldMapper = docMapper.mappers().getMapper("shape");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;
@@ -600,7 +600,7 @@ public class GeoShapeFieldMapperTests extends ESSingleNodeTestCase {
             .endObject().endObject());
 
         DocumentMapper defaultMapper = createIndex("test").mapperService().documentMapperParser().parse("type1", new CompressedXContent(mapping));
-        FieldMapper fieldMapper = defaultMapper.mappers().getMapper("location");
+        Mapper fieldMapper = defaultMapper.mappers().getMapper("location");
         assertThat(fieldMapper, instanceOf(GeoShapeFieldMapper.class));
 
         GeoShapeFieldMapper geoShapeFieldMapper = (GeoShapeFieldMapper) fieldMapper;

server/src/test/java/org/elasticsearch/index/mapper/JavaMultiFieldMergeTests.java

@@ -38,69 +38,68 @@ public class JavaMultiFieldMergeTests extends ESSingleNodeTestCase {
         String mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/test-mapping1.json");
         MapperService mapperService = createIndex("test").mapperService();
 
-        DocumentMapper docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), nullValue());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
+        assertThat(mapperService.fullName("name.indexed"), nullValue());
 
         BytesReference json = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("name", "some name").endObject());
-        Document doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = mapperService.documentMapper().parse(
+            SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
         IndexableField f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
         assertThat(f, nullValue());
 
         mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/test-mapping2.json");
-        docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed2"), nullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed3"), nullValue());
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed2"), nullValue());
+        assertThat(mapperService.fullName("name.not_indexed3"), nullValue());
 
-        doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
+        doc = mapperService.documentMapper().parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
         f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
         assertThat(f, notNullValue());
 
         mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/test-mapping3.json");
-        docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed2"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed3"), nullValue());
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed2"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed3"), nullValue());
 
         mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/test-mapping4.json");
-        docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed2"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed3"), notNullValue());
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed2"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed3"), notNullValue());
     }
 
     public void testUpgradeFromMultiFieldTypeToMultiFields() throws Exception {
         String mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/test-mapping1.json");
         MapperService mapperService = createIndex("test").mapperService();
 
-        DocumentMapper docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), nullValue());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
+        assertThat(mapperService.fullName("name.indexed"), nullValue());
 
         BytesReference json = BytesReference.bytes(XContentFactory.jsonBuilder().startObject().field("name", "some name").endObject());
-        Document doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = mapperService.documentMapper().parse(
+            SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
         IndexableField f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
@@ -108,32 +107,31 @@ public class JavaMultiFieldMergeTests extends ESSingleNodeTestCase {
 
 
         mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/upgrade1.json");
-        docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed2"), nullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed3"), nullValue());
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed2"), nullValue());
+        assertThat(mapperService.fullName("name.not_indexed3"), nullValue());
 
-        doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
+        doc = mapperService.documentMapper().parse(
+            SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
         f = doc.getField("name");
         assertThat(f, notNullValue());
         f = doc.getField("name.indexed");
         assertThat(f, notNullValue());
 
         mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/upgrade2.json");
-        docMapper = mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
+        mapperService.merge("person", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
 
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed2"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed3"), nullValue());
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed2"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed3"), nullValue());
 
 
         mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/multifield/merge/upgrade3.json");
@@ -146,10 +144,10 @@ public class JavaMultiFieldMergeTests extends ESSingleNodeTestCase {
         }
 
         // There are conflicts, so the `name.not_indexed3` has not been added
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed2"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed3"), nullValue());
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed2"), notNullValue());
+        assertThat(mapperService.fullName("name.not_indexed3"), nullValue());
     }
 }

server/src/test/java/org/elasticsearch/index/mapper/MapperMergeValidatorTests.java

@@ -0,0 +1,118 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.index.mapper;
+
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.test.ESTestCase;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.singletonList;
+
+public class MapperMergeValidatorTests extends ESTestCase {
+
+    public void testDuplicateFieldAliasAndObject() {
+        ObjectMapper objectMapper = createObjectMapper("some.path");
+        FieldAliasMapper aliasMapper = new FieldAliasMapper("path", "some.path", "field");
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () ->
+            MapperMergeValidator.validateMapperStructure("type",
+                singletonList(objectMapper),
+                emptyList(),
+                singletonList(aliasMapper),
+                emptyMap(),
+                new FieldTypeLookup()));
+        assertEquals("Field [some.path] is defined both as an object and a field in [type]", e.getMessage());
+    }
+
+    public void testFieldAliasWithNestedScope() {
+        ObjectMapper objectMapper = createNestedObjectMapper("nested");
+        FieldAliasMapper aliasMapper = new FieldAliasMapper("alias", "nested.alias", "nested.field");
+
+        MapperMergeValidator.validateFieldReferences(emptyList(),
+            singletonList(aliasMapper),
+            Collections.singletonMap("nested", objectMapper),
+            new FieldTypeLookup());
+    }
+
+    public void testFieldAliasWithDifferentObjectScopes() {
+        Map<String, ObjectMapper> fullPathObjectMappers = new HashMap<>();
+        fullPathObjectMappers.put("object1", createObjectMapper("object1"));
+        fullPathObjectMappers.put("object2", createObjectMapper("object2"));
+
+        FieldAliasMapper aliasMapper = new FieldAliasMapper("alias", "object2.alias", "object1.field");
+
+        MapperMergeValidator.validateFieldReferences(emptyList(),
+            singletonList(aliasMapper),
+            fullPathObjectMappers,
+            new FieldTypeLookup());
+    }
+
+    public void testFieldAliasWithNestedTarget() {
+        ObjectMapper objectMapper = createNestedObjectMapper("nested");
+        FieldAliasMapper aliasMapper = new FieldAliasMapper("alias", "alias", "nested.field");
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () ->
+            MapperMergeValidator.validateFieldReferences(emptyList(),
+                singletonList(aliasMapper),
+                Collections.singletonMap("nested", objectMapper),
+                new FieldTypeLookup()));
+
+        String expectedMessage = "Invalid [path] value [nested.field] for field alias [alias]: " +
+            "an alias must have the same nested scope as its target. The alias is not nested, " +
+            "but the target's nested scope is [nested].";
+        assertEquals(expectedMessage, e.getMessage());
+    }
+
+    public void testFieldAliasWithDifferentNestedScopes() {
+        Map<String, ObjectMapper> fullPathObjectMappers = new HashMap<>();
+        fullPathObjectMappers.put("nested1", createNestedObjectMapper("nested1"));
+        fullPathObjectMappers.put("nested2", createNestedObjectMapper("nested2"));
+
+        FieldAliasMapper aliasMapper = new FieldAliasMapper("alias", "nested2.alias", "nested1.field");
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () ->
+            MapperMergeValidator.validateFieldReferences(emptyList(),
+                singletonList(aliasMapper),
+                fullPathObjectMappers,
+                new FieldTypeLookup()));
+
+
+        String expectedMessage = "Invalid [path] value [nested1.field] for field alias [nested2.alias]: " +
+            "an alias must have the same nested scope as its target. The alias's nested scope is [nested2], " +
+            "but the target's nested scope is [nested1].";
+        assertEquals(expectedMessage, e.getMessage());
+    }
+
+    private static ObjectMapper createObjectMapper(String name) {
+        return new ObjectMapper(name, name, true,
+            ObjectMapper.Nested.NO,
+            ObjectMapper.Dynamic.FALSE, emptyMap(), Settings.EMPTY);
+    }
+
+    private static ObjectMapper createNestedObjectMapper(String name) {
+        return new ObjectMapper(name, name, true,
+            ObjectMapper.Nested.newNested(false, false),
+            ObjectMapper.Dynamic.FALSE, emptyMap(), Settings.EMPTY);
+    }
+}

server/src/test/java/org/elasticsearch/index/mapper/MapperServiceTests.java

@@ -235,6 +235,41 @@ public class MapperServiceTests extends ESSingleNodeTestCase {
             containsString("cannot have nested fields when index sort is activated"));
     }
 
+     public void testFieldAliasWithMismatchedNestedScope() throws Throwable {
+        IndexService indexService = createIndex("test");
+        MapperService mapperService = indexService.mapperService();
+
+        CompressedXContent mapping = new CompressedXContent(BytesReference.bytes(
+            XContentFactory.jsonBuilder().startObject()
+                .startObject("properties")
+                    .startObject("nested")
+                        .field("type", "nested")
+                        .startObject("properties")
+                            .startObject("field")
+                                .field("type", "text")
+                            .endObject()
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject()));
+
+        mapperService.merge("type", mapping, MergeReason.MAPPING_UPDATE);
+
+        CompressedXContent mappingUpdate = new CompressedXContent(BytesReference.bytes(
+            XContentFactory.jsonBuilder().startObject()
+                .startObject("properties")
+                    .startObject("alias")
+                        .field("type", "alias")
+                        .field("path", "nested.field")
+                    .endObject()
+                .endObject()
+            .endObject()));
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+            () -> mapperService.merge("type", mappingUpdate, MergeReason.MAPPING_UPDATE));
+        assertThat(e.getMessage(), containsString("Invalid [path] value [nested.field] for field alias [alias]"));
+    }
+
     public void testForbidMultipleTypes() throws IOException {
         String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject());
         MapperService mapperService = createIndex("test").mapperService();

server/src/test/java/org/elasticsearch/index/mapper/MultiFieldTests.java

@@ -32,6 +32,7 @@ import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.mapper.ParseContext.Document;
+import org.elasticsearch.index.mapper.TextFieldMapper.TextFieldType;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
 import java.io.IOException;
@@ -55,9 +56,15 @@ public class MultiFieldTests extends ESSingleNodeTestCase {
     }
 
     private void testMultiField(String mapping) throws Exception {
-        DocumentMapper docMapper = createIndex("test").mapperService().documentMapperParser().parse("person", new CompressedXContent(mapping));
+        IndexService indexService = createIndex("test");
+        MapperService mapperService = indexService.mapperService();
+
+        indexService.mapperService().merge("person", new CompressedXContent(mapping),
+            MapperService.MergeReason.MAPPING_UPDATE);
+
         BytesReference json = new BytesArray(copyToBytesFromClasspath("/org/elasticsearch/index/mapper/multifield/test-data.json"));
-        Document doc = docMapper.parse(SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
+        Document doc = mapperService.documentMapper().parse(
+            SourceToParse.source("test", "person", "1", json, XContentType.JSON)).rootDoc();
 
         IndexableField f = doc.getField("name");
         assertThat(f.name(), equalTo("name"));
@@ -84,37 +91,37 @@ public class MultiFieldTests extends ESSingleNodeTestCase {
         assertThat(f.name(), equalTo("object1.multi1.string"));
         assertThat(f.binaryValue(), equalTo(new BytesRef("2010-01-01")));
 
-        assertThat(docMapper.mappers().getMapper("name"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name"), instanceOf(TextFieldMapper.class));
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name").fieldType().stored(), equalTo(true));
-        assertThat(docMapper.mappers().getMapper("name").fieldType().tokenized(), equalTo(true));
+        assertThat(mapperService.fullName("name"), notNullValue());
+        assertThat(mapperService.fullName("name"), instanceOf(TextFieldType.class));
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name").indexOptions());
+        assertThat(mapperService.fullName("name").stored(), equalTo(true));
+        assertThat(mapperService.fullName("name").tokenized(), equalTo(true));
 
-        assertThat(docMapper.mappers().getMapper("name.indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.indexed"), instanceOf(TextFieldMapper.class));
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name.indexed").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.indexed").fieldType().stored(), equalTo(false));
-        assertThat(docMapper.mappers().getMapper("name.indexed").fieldType().tokenized(), equalTo(true));
+        assertThat(mapperService.fullName("name.indexed"), notNullValue());
+        assertThat(mapperService.fullName("name"), instanceOf(TextFieldType.class));
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name.indexed").indexOptions());
+        assertThat(mapperService.fullName("name.indexed").stored(), equalTo(false));
+        assertThat(mapperService.fullName("name.indexed").tokenized(), equalTo(true));
 
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed"), instanceOf(TextFieldMapper.class));
-        assertEquals(IndexOptions.NONE, docMapper.mappers().getMapper("name.not_indexed").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.not_indexed").fieldType().stored(), equalTo(true));
-        assertThat(docMapper.mappers().getMapper("name.not_indexed").fieldType().tokenized(), equalTo(true));
+        assertThat(mapperService.fullName("name.not_indexed"), notNullValue());
+        assertThat(mapperService.fullName("name"), instanceOf(TextFieldType.class));
+        assertEquals(IndexOptions.NONE, mapperService.fullName("name.not_indexed").indexOptions());
+        assertThat(mapperService.fullName("name.not_indexed").stored(), equalTo(true));
+        assertThat(mapperService.fullName("name.not_indexed").tokenized(), equalTo(true));
 
-        assertThat(docMapper.mappers().getMapper("name.test1"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("name.test1"), instanceOf(TextFieldMapper.class));
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("name.test1").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("name.test1").fieldType().stored(), equalTo(true));
-        assertThat(docMapper.mappers().getMapper("name.test1").fieldType().tokenized(), equalTo(true));
-        assertThat(docMapper.mappers().getMapper("name.test1").fieldType().eagerGlobalOrdinals(), equalTo(true));
+        assertThat(mapperService.fullName("name.test1"), notNullValue());
+        assertThat(mapperService.fullName("name"), instanceOf(TextFieldType.class));
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("name.test1").indexOptions());
+        assertThat(mapperService.fullName("name.test1").stored(), equalTo(true));
+        assertThat(mapperService.fullName("name.test1").tokenized(), equalTo(true));
+        assertThat(mapperService.fullName("name.test1").eagerGlobalOrdinals(), equalTo(true));
 
-        assertThat(docMapper.mappers().getMapper("object1.multi1"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("object1.multi1"), instanceOf(DateFieldMapper.class));
-        assertThat(docMapper.mappers().getMapper("object1.multi1.string"), notNullValue());
-        assertThat(docMapper.mappers().getMapper("object1.multi1.string"), instanceOf(KeywordFieldMapper.class));
-        assertNotSame(IndexOptions.NONE, docMapper.mappers().getMapper("object1.multi1.string").fieldType().indexOptions());
-        assertThat(docMapper.mappers().getMapper("object1.multi1.string").fieldType().tokenized(), equalTo(false));
+        assertThat(mapperService.fullName("object1.multi1"), notNullValue());
+        assertThat(mapperService.fullName("object1.multi1"), instanceOf(DateFieldMapper.DateFieldType.class));
+        assertThat(mapperService.fullName("object1.multi1.string"), notNullValue());
+        assertThat(mapperService.fullName("object1.multi1.string"), instanceOf(KeywordFieldMapper.KeywordFieldType.class));
+        assertNotSame(IndexOptions.NONE, mapperService.fullName("object1.multi1.string").indexOptions());
+        assertThat(mapperService.fullName("object1.multi1.string").tokenized(), equalTo(false));
     }
 
     public void testBuildThenParse() throws Exception {

server/src/test/java/org/elasticsearch/index/mapper/PathMapperTests.java

@@ -20,7 +20,6 @@
 package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.common.compress.CompressedXContent;
-import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
 import java.io.IOException;

server/src/test/java/org/elasticsearch/index/mapper/PathMatchDynamicTemplateTests.java

@@ -23,10 +23,7 @@ import org.apache.lucene.index.IndexableField;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
-import org.elasticsearch.index.mapper.DocumentMapper;
-import org.elasticsearch.index.mapper.FieldMapper;
 import org.elasticsearch.index.mapper.ParseContext.Document;
-import org.elasticsearch.index.mapper.ParsedDocument;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
 import static org.elasticsearch.test.StreamsUtils.copyToBytesFromClasspath;
@@ -38,13 +35,14 @@ public class PathMatchDynamicTemplateTests extends ESSingleNodeTestCase {
         String mapping = copyToStringFromClasspath("/org/elasticsearch/index/mapper/dynamictemplate/pathmatch/test-mapping.json");
         IndexService index = createIndex("test");
         client().admin().indices().preparePutMapping("test").setType("person").setSource(mapping, XContentType.JSON).get();
-        DocumentMapper docMapper = index.mapperService().documentMapper("person");
+
+        MapperService mapperService = index.mapperService();
+
         byte[] json = copyToBytesFromClasspath("/org/elasticsearch/index/mapper/dynamictemplate/pathmatch/test-data.json");
-        ParsedDocument parsedDoc = docMapper.parse(SourceToParse.source("test", "person", "1", new BytesArray(json),
-                XContentType.JSON));
+        ParsedDocument parsedDoc = mapperService.documentMapper().parse(
+            SourceToParse.source("test", "person", "1", new BytesArray(json), XContentType.JSON));
         client().admin().indices().preparePutMapping("test").setType("person")
             .setSource(parsedDoc.dynamicMappingsUpdate().toString(), XContentType.JSON).get();
-        docMapper = index.mapperService().documentMapper("person");
         Document doc = parsedDoc.rootDoc();
 
         IndexableField f = doc.getField("name");
@@ -52,26 +50,26 @@ public class PathMatchDynamicTemplateTests extends ESSingleNodeTestCase {
         assertThat(f.stringValue(), equalTo("top_level"));
         assertThat(f.fieldType().stored(), equalTo(false));
 
-        FieldMapper fieldMapper = docMapper.mappers().getMapper("name");
-        assertThat(fieldMapper.fieldType().stored(), equalTo(false));
+        MappedFieldType fieldType = mapperService.fullName("name");
+        assertThat(fieldType.stored(), equalTo(false));
 
         f = doc.getField("obj1.name");
         assertThat(f.name(), equalTo("obj1.name"));
         assertThat(f.fieldType().stored(), equalTo(true));
 
-        fieldMapper = docMapper.mappers().getMapper("obj1.name");
-        assertThat(fieldMapper.fieldType().stored(), equalTo(true));
+        fieldType = mapperService.fullName("obj1.name");
+        assertThat(fieldType.stored(), equalTo(true));
 
         f = doc.getField("obj1.obj2.name");
         assertThat(f.name(), equalTo("obj1.obj2.name"));
         assertThat(f.fieldType().stored(), equalTo(false));
 
-        fieldMapper = docMapper.mappers().getMapper("obj1.obj2.name");
-        assertThat(fieldMapper.fieldType().stored(), equalTo(false));
+        fieldType = mapperService.fullName("obj1.obj2.name");
+        assertThat(fieldType.stored(), equalTo(false));
 
         // verify more complex path_match expressions
 
-        fieldMapper = docMapper.mappers().getMapper("obj3.obj4.prop1");
-        assertNotNull(fieldMapper);
+        fieldType = mapperService.fullName("obj3.obj4.prop1");
+        assertNotNull(fieldType);
     }
 }

server/src/test/java/org/elasticsearch/index/mapper/StoredNumericValuesTests.java

@@ -28,13 +28,14 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.lucene.Lucene;
+import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.fieldvisitor.CustomFieldsVisitor;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
-import java.util.Collections;
+import java.util.Set;
 
 import static org.hamcrest.Matchers.equalTo;
 
@@ -84,9 +85,11 @@ public class StoredNumericValuesTests extends ESSingleNodeTestCase {
         DirectoryReader reader = DirectoryReader.open(writer);
         IndexSearcher searcher = new IndexSearcher(reader);
 
-        CustomFieldsVisitor fieldsVisitor = new CustomFieldsVisitor(
-                Collections.emptySet(), Collections.singletonList("field*"), false);
+        Set<String> fieldNames = Sets.newHashSet("field1", "field2", "field3", "field4", "field5",
+            "field6", "field7", "field8", "field9", "field10");
+        CustomFieldsVisitor fieldsVisitor = new CustomFieldsVisitor(fieldNames, false);
         searcher.doc(0, fieldsVisitor);
+
         fieldsVisitor.postProcess(mapperService);
         assertThat(fieldsVisitor.fields().size(), equalTo(10));
         assertThat(fieldsVisitor.fields().get("field1").size(), equalTo(1));

server/src/test/java/org/elasticsearch/index/mapper/TextFieldMapperTests.java

@@ -490,9 +490,10 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
                 .endObject().endObject());
 
         DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
-
         assertEquals(mapping, mapper.mappingSource().toString());
-        assertTrue(mapper.mappers().getMapper("field").fieldType().eagerGlobalOrdinals());
+
+        FieldMapper fieldMapper = (FieldMapper) mapper.mappers().getMapper("field");
+        assertTrue(fieldMapper.fieldType().eagerGlobalOrdinals());
     }
 
     public void testFielddata() throws IOException {
@@ -504,8 +505,10 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
         DocumentMapper disabledMapper = parser.parse("type", new CompressedXContent(mapping));
         assertEquals(mapping, disabledMapper.mappingSource().toString());
-        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
-                () -> disabledMapper.mappers().getMapper("field").fieldType().fielddataBuilder("test"));
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
+            FieldMapper fieldMapper = (FieldMapper) disabledMapper.mappers().getMapper("field");
+            fieldMapper.fieldType().fielddataBuilder("test");
+        });
         assertThat(e.getMessage(), containsString("Fielddata is disabled"));
 
         mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
@@ -518,7 +521,9 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
         DocumentMapper enabledMapper = parser.parse("type", new CompressedXContent(mapping));
 
         assertEquals(mapping, enabledMapper.mappingSource().toString());
-        enabledMapper.mappers().getMapper("field").fieldType().fielddataBuilder("test"); // no exception this time
+
+        FieldMapper enabledFieldMapper = (FieldMapper) enabledMapper.mappers().getMapper("field");
+        enabledFieldMapper.fieldType().fielddataBuilder("test"); // no exception this time
 
         String illegalMapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
                 .startObject("properties").startObject("field")
@@ -547,7 +552,9 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
         DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
         assertEquals(mapping, mapper.mappingSource().toString());
-        TextFieldType fieldType = (TextFieldType) mapper.mappers().getMapper("field").fieldType();
+        TextFieldMapper fieldMapper = (TextFieldMapper) mapper.mappers().getMapper("field");
+        TextFieldType fieldType = fieldMapper.fieldType();
+
         assertThat(fieldType.fielddataMinFrequency(), equalTo(2d));
         assertThat(fieldType.fielddataMaxFrequency(), equalTo((double) Integer.MAX_VALUE));
         assertThat(fieldType.fielddataMinSegmentSize(), equalTo(1000));
@@ -630,7 +637,7 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
             DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
-            FieldMapper prefix = mapper.mappers().getMapper("field._index_prefix");
+            FieldMapper prefix = (FieldMapper) mapper.mappers().getMapper("field._index_prefix");
             FieldType ft = prefix.fieldType;
             assertEquals(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS, ft.indexOptions());
         }
@@ -646,7 +653,7 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
             DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
-            FieldMapper prefix = mapper.mappers().getMapper("field._index_prefix");
+            FieldMapper prefix = (FieldMapper) mapper.mappers().getMapper("field._index_prefix");
             FieldType ft = prefix.fieldType;
             assertEquals(IndexOptions.DOCS, ft.indexOptions());
             assertFalse(ft.storeTermVectors());
@@ -663,7 +670,7 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
             DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
-            FieldMapper prefix = mapper.mappers().getMapper("field._index_prefix");
+            FieldMapper prefix = (FieldMapper) mapper.mappers().getMapper("field._index_prefix");
             FieldType ft = prefix.fieldType;
             if (indexService.getIndexSettings().getIndexVersionCreated().onOrAfter(Version.V_6_4_0)) {
                 assertEquals(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS, ft.indexOptions());
@@ -684,7 +691,7 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
             DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
-            FieldMapper prefix = mapper.mappers().getMapper("field._index_prefix");
+            FieldMapper prefix = (FieldMapper) mapper.mappers().getMapper("field._index_prefix");
             FieldType ft = prefix.fieldType;
             if (indexService.getIndexSettings().getIndexVersionCreated().onOrAfter(Version.V_6_4_0)) {
                 assertEquals(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS, ft.indexOptions());
@@ -705,7 +712,7 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
             DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
 
-            FieldMapper prefix = mapper.mappers().getMapper("field._index_prefix");
+            FieldMapper prefix = (FieldMapper) mapper.mappers().getMapper("field._index_prefix");
             FieldType ft = prefix.fieldType;
             if (indexService.getIndexSettings().getIndexVersionCreated().onOrAfter(Version.V_6_4_0)) {
                 assertEquals(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS, ft.indexOptions());
@@ -836,10 +843,13 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
 
             assertThat(mapper.mappers().getMapper("field._index_prefix").toString(), containsString("prefixChars=1:10"));
 
-            Query q = mapper.mappers().getMapper("field").fieldType().prefixQuery("goin", CONSTANT_SCORE_REWRITE, queryShardContext);
+            FieldMapper fieldMapper = (FieldMapper) mapper.mappers().getMapper("field");
+            MappedFieldType fieldType = fieldMapper.fieldType;
+
+            Query q = fieldType.prefixQuery("goin", CONSTANT_SCORE_REWRITE, queryShardContext);
+
             assertEquals(new ConstantScoreQuery(new TermQuery(new Term("field._index_prefix", "goin"))), q);
-            q = mapper.mappers().getMapper("field").fieldType().prefixQuery("internationalisatio",
-                CONSTANT_SCORE_REWRITE, queryShardContext);
+            q = fieldType.prefixQuery("internationalisatio", CONSTANT_SCORE_REWRITE, queryShardContext);
             assertEquals(new PrefixQuery(new Term("field", "internationalisatio")), q);
 
             ParsedDocument doc = mapper.parse(SourceToParse.source("test", "type", "1", BytesReference
@@ -864,17 +874,16 @@ public class TextFieldMapperTests extends ESSingleNodeTestCase {
             CompressedXContent json = new CompressedXContent(mapping);
             DocumentMapper mapper = parser.parse("type", json);
 
-            Query q1 = mapper.mappers().getMapper("field").fieldType().prefixQuery("g",
-                CONSTANT_SCORE_REWRITE, queryShardContext);
+            FieldMapper fieldMapper = (FieldMapper) mapper.mappers().getMapper("field");
+            MappedFieldType fieldType = fieldMapper.fieldType;
+
+            Query q1 = fieldType.prefixQuery("g", CONSTANT_SCORE_REWRITE, queryShardContext);
             assertThat(q1, instanceOf(PrefixQuery.class));
-            Query q2 = mapper.mappers().getMapper("field").fieldType().prefixQuery("go",
-                CONSTANT_SCORE_REWRITE, queryShardContext);
+            Query q2 = fieldType.prefixQuery("go", CONSTANT_SCORE_REWRITE, queryShardContext);
             assertThat(q2, instanceOf(ConstantScoreQuery.class));
-            Query q5 = mapper.mappers().getMapper("field").fieldType().prefixQuery("going",
-                CONSTANT_SCORE_REWRITE, queryShardContext);
+            Query q5 = fieldType.prefixQuery("going", CONSTANT_SCORE_REWRITE, queryShardContext);
             assertThat(q5, instanceOf(ConstantScoreQuery.class));
-            Query q6 = mapper.mappers().getMapper("field").fieldType().prefixQuery("goings",
-                CONSTANT_SCORE_REWRITE, queryShardContext);
+            Query q6 = fieldType.prefixQuery("goings", CONSTANT_SCORE_REWRITE, queryShardContext);
             assertThat(q6, instanceOf(PrefixQuery.class));
         }
 

server/src/test/java/org/elasticsearch/index/query/CommonTermsQueryBuilderTests.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.query;
 
+import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.ExtendedCommonTermsQuery;
 import org.apache.lucene.search.Query;
 import org.elasticsearch.common.ParsingException;
@@ -27,6 +28,7 @@ import org.elasticsearch.test.AbstractQueryTestCase;
 
 import java.io.IOException;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import static org.elasticsearch.index.query.QueryBuilders.commonTermsQuery;
@@ -39,19 +41,16 @@ public class CommonTermsQueryBuilderTests extends AbstractQueryTestCase<CommonTe
 
     @Override
     protected CommonTermsQueryBuilder doCreateTestQueryBuilder() {
-        CommonTermsQueryBuilder query;
-
         int numberOfTerms = randomIntBetween(0, 10);
         StringBuilder text = new StringBuilder("");
         for (int i = 0; i < numberOfTerms; i++) {
             text.append(randomAlphaOfLengthBetween(1, 10)).append(" ");
         }
-        // mapped or unmapped field
-        if (randomBoolean()) {
-            query = new CommonTermsQueryBuilder(STRING_FIELD_NAME, text.toString());
-        } else {
-            query = new CommonTermsQueryBuilder(randomAlphaOfLengthBetween(1, 10), text.toString());
-        }
+
+        String fieldName = randomFrom(STRING_FIELD_NAME,
+            STRING_ALIAS_FIELD_NAME,
+            randomAlphaOfLengthBetween(1, 10));
+        CommonTermsQueryBuilder query = new CommonTermsQueryBuilder(fieldName, text.toString());
 
         if (randomBoolean()) {
             query.cutoffFrequency(randomIntBetween(1, 10));
@@ -100,6 +99,14 @@ public class CommonTermsQueryBuilderTests extends AbstractQueryTestCase<CommonTe
     protected void doAssertLuceneQuery(CommonTermsQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         assertThat(query, instanceOf(ExtendedCommonTermsQuery.class));
         ExtendedCommonTermsQuery extendedCommonTermsQuery = (ExtendedCommonTermsQuery) query;
+
+        List<Term> terms = extendedCommonTermsQuery.getTerms();
+        if (!terms.isEmpty()) {
+            String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+            String actualFieldName = terms.iterator().next().field();
+            assertThat(actualFieldName, equalTo(expectedFieldName));
+        }
+
         assertThat(extendedCommonTermsQuery.getHighFreqMinimumNumberShouldMatchSpec(), equalTo(queryBuilder.highFreqMinimumShouldMatch()));
         assertThat(extendedCommonTermsQuery.getLowFreqMinimumNumberShouldMatchSpec(), equalTo(queryBuilder.lowFreqMinimumShouldMatch()));
     }

server/src/test/java/org/elasticsearch/index/query/ExistsQueryBuilderTests.java

@@ -76,7 +76,7 @@ public class ExistsQueryBuilderTests extends AbstractQueryTestCase<ExistsQueryBu
             if (fields.size() == 1) {
                 assertThat(query, instanceOf(ConstantScoreQuery.class));
                 ConstantScoreQuery constantScoreQuery = (ConstantScoreQuery) query;
-                String field = fields.iterator().next();
+                String field = expectedFieldName(fields.iterator().next());
                 assertThat(constantScoreQuery.getQuery(), instanceOf(TermQuery.class));
                 TermQuery termQuery = (TermQuery) constantScoreQuery.getQuery();
                 assertEquals(field, termQuery.getTerm().text());
@@ -99,7 +99,7 @@ public class ExistsQueryBuilderTests extends AbstractQueryTestCase<ExistsQueryBu
         } else if (fields.size() == 1) {
             assertThat(query, instanceOf(ConstantScoreQuery.class));
             ConstantScoreQuery constantScoreQuery = (ConstantScoreQuery) query;
-            String field = fields.iterator().next();
+            String field = expectedFieldName(fields.iterator().next());
             if (context.getQueryShardContext().getObjectMapper(field) != null) {
                 assertThat(constantScoreQuery.getQuery(), instanceOf(BooleanQuery.class));
                 BooleanQuery booleanQuery = (BooleanQuery) constantScoreQuery.getQuery();

server/src/test/java/org/elasticsearch/index/query/FieldMaskingSpanQueryBuilderTests.java

@@ -21,7 +21,6 @@ package org.elasticsearch.index.query;
 
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.spans.FieldMaskingSpanQuery;
-import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.search.internal.SearchContext;
 import org.elasticsearch.test.AbstractQueryTestCase;
 
@@ -45,11 +44,7 @@ public class FieldMaskingSpanQueryBuilderTests extends AbstractQueryTestCase<Fie
 
     @Override
     protected void doAssertLuceneQuery(FieldMaskingSpanQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
-        String fieldInQuery = queryBuilder.fieldName();
-        MappedFieldType fieldType = context.getQueryShardContext().fieldMapper(fieldInQuery);
-        if (fieldType != null) {
-            fieldInQuery = fieldType.name();
-        }
+        String fieldInQuery = expectedFieldName(queryBuilder.fieldName());
         assertThat(query, instanceOf(FieldMaskingSpanQuery.class));
         FieldMaskingSpanQuery fieldMaskingSpanQuery = (FieldMaskingSpanQuery) query;
         assertThat(fieldMaskingSpanQuery.getField(), equalTo(fieldInQuery));

server/src/test/java/org/elasticsearch/index/query/FuzzyQueryBuilderTests.java

@@ -41,7 +41,8 @@ public class FuzzyQueryBuilderTests extends AbstractQueryTestCase<FuzzyQueryBuil
 
     @Override
     protected FuzzyQueryBuilder doCreateTestQueryBuilder() {
-        FuzzyQueryBuilder query = new FuzzyQueryBuilder(STRING_FIELD_NAME, getRandomValueForFieldName(STRING_FIELD_NAME));
+        String fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME);
+        FuzzyQueryBuilder query = new FuzzyQueryBuilder(fieldName, getRandomValueForFieldName(fieldName));
         if (randomBoolean()) {
             query.fuzziness(randomFuzziness(query.fieldName()));
         }
@@ -76,6 +77,11 @@ public class FuzzyQueryBuilderTests extends AbstractQueryTestCase<FuzzyQueryBuil
     @Override
     protected void doAssertLuceneQuery(FuzzyQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         assertThat(query, instanceOf(FuzzyQuery.class));
+
+        FuzzyQuery fuzzyQuery = (FuzzyQuery) query;
+        String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+        String actualFieldName = fuzzyQuery.getTerm().field();
+        assertThat(actualFieldName, equalTo(expectedFieldName));
     }
 
     public void testIllegalArguments() {

server/src/test/java/org/elasticsearch/index/query/GeoBoundingBoxQueryBuilderTests.java

@@ -39,6 +39,7 @@ import java.io.IOException;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.Matchers.startsWith;
 
 public class GeoBoundingBoxQueryBuilderTests extends AbstractQueryTestCase<GeoBoundingBoxQueryBuilder> {
     /** Randomly generate either NaN or one of the two infinity values. */
@@ -46,7 +47,8 @@ public class GeoBoundingBoxQueryBuilderTests extends AbstractQueryTestCase<GeoBo
 
     @Override
     protected GeoBoundingBoxQueryBuilder doCreateTestQueryBuilder() {
-        GeoBoundingBoxQueryBuilder builder = new GeoBoundingBoxQueryBuilder(GEO_POINT_FIELD_NAME);
+        String fieldName = randomFrom(GEO_POINT_FIELD_NAME, GEO_POINT_ALIAS_FIELD_NAME);
+        GeoBoundingBoxQueryBuilder builder = new GeoBoundingBoxQueryBuilder(fieldName);
         Rectangle box = RandomShapeGenerator.xRandomRectangle(random(), RandomShapeGenerator.xRandomPoint(random()));
 
         if (randomBoolean()) {
@@ -117,7 +119,7 @@ public class GeoBoundingBoxQueryBuilderTests extends AbstractQueryTestCase<GeoBo
     public void testExceptionOnMissingTypes() throws IOException {
         assumeTrue("test runs only when at least a type is registered", getCurrentTypes().length == 0);
         QueryShardException e = expectThrows(QueryShardException.class, super::testToQuery);
-        assertEquals("failed to find geo_point field [mapped_geo_point]", e.getMessage());
+        assertThat(e.getMessage(), startsWith("failed to find geo_point field [mapped_geo_point"));
     }
 
     public void testBrokenCoordinateCannotBeSet() {
@@ -216,13 +218,14 @@ public class GeoBoundingBoxQueryBuilderTests extends AbstractQueryTestCase<GeoBo
             assertTrue("Found no indexed geo query.", query instanceof MatchNoDocsQuery);
         } else if (query instanceof IndexOrDocValuesQuery) { // TODO: remove the if statement once we always use LatLonPoint
             Query indexQuery = ((IndexOrDocValuesQuery) query).getIndexQuery();
-            assertEquals(LatLonPoint.newBoxQuery(queryBuilder.fieldName(),
+            String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+            assertEquals(LatLonPoint.newBoxQuery(expectedFieldName,
                     queryBuilder.bottomRight().lat(),
                     queryBuilder.topLeft().lat(),
                     queryBuilder.topLeft().lon(),
                     queryBuilder.bottomRight().lon()), indexQuery);
             Query dvQuery = ((IndexOrDocValuesQuery) query).getRandomAccessQuery();
-            assertEquals(LatLonDocValuesField.newSlowBoxQuery(queryBuilder.fieldName(),
+            assertEquals(LatLonDocValuesField.newSlowBoxQuery(expectedFieldName,
                     queryBuilder.bottomRight().lat(),
                     queryBuilder.topLeft().lat(),
                     queryBuilder.topLeft().lon(),

server/src/test/java/org/elasticsearch/index/query/GeoDistanceQueryBuilderTests.java

@@ -43,7 +43,8 @@ public class GeoDistanceQueryBuilderTests extends AbstractQueryTestCase<GeoDista
 
     @Override
     protected GeoDistanceQueryBuilder doCreateTestQueryBuilder() {
-        GeoDistanceQueryBuilder qb = new GeoDistanceQueryBuilder(GEO_POINT_FIELD_NAME);
+        String fieldName = randomFrom(GEO_POINT_FIELD_NAME, GEO_POINT_ALIAS_FIELD_NAME);
+        GeoDistanceQueryBuilder qb = new GeoDistanceQueryBuilder(fieldName);
         String distance = "" + randomDouble();
         if (randomBoolean()) {
             DistanceUnit unit = randomFrom(DistanceUnit.values());
@@ -130,13 +131,15 @@ public class GeoDistanceQueryBuilderTests extends AbstractQueryTestCase<GeoDista
         // TODO: remove the if statement once we always use LatLonPoint
         if (query instanceof IndexOrDocValuesQuery) {
             Query indexQuery = ((IndexOrDocValuesQuery) query).getIndexQuery();
-            assertEquals(LatLonPoint.newDistanceQuery(queryBuilder.fieldName(),
+
+            String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+            assertEquals(LatLonPoint.newDistanceQuery(expectedFieldName,
                     queryBuilder.point().lat(),
                     queryBuilder.point().lon(),
                     queryBuilder.distance()),
                     indexQuery);
             Query dvQuery = ((IndexOrDocValuesQuery) query).getRandomAccessQuery();
-            assertEquals(LatLonDocValuesField.newSlowDistanceQuery(queryBuilder.fieldName(),
+            assertEquals(LatLonDocValuesField.newSlowDistanceQuery(expectedFieldName,
                     queryBuilder.point().lat(),
                     queryBuilder.point().lon(),
                     queryBuilder.distance()),

server/src/test/java/org/elasticsearch/index/query/GeoPolygonQueryBuilderTests.java

@@ -44,8 +44,9 @@ import static org.hamcrest.CoreMatchers.notNullValue;
 public class GeoPolygonQueryBuilderTests extends AbstractQueryTestCase<GeoPolygonQueryBuilder> {
     @Override
     protected GeoPolygonQueryBuilder doCreateTestQueryBuilder() {
+        String fieldName = randomFrom(GEO_POINT_FIELD_NAME, GEO_POINT_ALIAS_FIELD_NAME);
         List<GeoPoint> polygon = randomPolygon();
-        GeoPolygonQueryBuilder builder = new GeoPolygonQueryBuilder(GEO_POINT_FIELD_NAME, polygon);
+        GeoPolygonQueryBuilder builder = new GeoPolygonQueryBuilder(fieldName, polygon);
         if (randomBoolean()) {
             builder.setValidationMethod(randomFrom(GeoValidationMethod.values()));
         }

server/src/test/java/org/elasticsearch/index/query/MatchPhrasePrefixQueryBuilderTests.java

@@ -42,13 +42,13 @@ import static org.hamcrest.Matchers.notNullValue;
 public class MatchPhrasePrefixQueryBuilderTests extends AbstractQueryTestCase<MatchPhrasePrefixQueryBuilder> {
     @Override
     protected MatchPhrasePrefixQueryBuilder doCreateTestQueryBuilder() {
-        String fieldName = randomFrom(STRING_FIELD_NAME, BOOLEAN_FIELD_NAME, INT_FIELD_NAME,
-                DOUBLE_FIELD_NAME, DATE_FIELD_NAME);
+        String fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME, BOOLEAN_FIELD_NAME,
+            INT_FIELD_NAME, DOUBLE_FIELD_NAME, DATE_FIELD_NAME);
         if (fieldName.equals(DATE_FIELD_NAME)) {
             assumeTrue("test runs only when at least a type is registered", getCurrentTypes().length > 0);
         }
         Object value;
-        if (fieldName.equals(STRING_FIELD_NAME)) {
+        if (isTextField(fieldName)) {
             int terms = randomIntBetween(0, 3);
             StringBuilder builder = new StringBuilder();
             for (int i = 0; i < terms; i++) {
@@ -61,7 +61,7 @@ public class MatchPhrasePrefixQueryBuilderTests extends AbstractQueryTestCase<Ma
 
         MatchPhrasePrefixQueryBuilder matchQuery = new MatchPhrasePrefixQueryBuilder(fieldName, value);
 
-        if (randomBoolean() && fieldName.equals(STRING_FIELD_NAME)) {
+        if (randomBoolean() && isTextField(fieldName)) {
             matchQuery.analyzer(randomFrom("simple", "keyword", "whitespace"));
         }
 

server/src/test/java/org/elasticsearch/index/query/MatchPhraseQueryBuilderTests.java

@@ -45,13 +45,13 @@ import static org.hamcrest.Matchers.notNullValue;
 public class MatchPhraseQueryBuilderTests extends AbstractQueryTestCase<MatchPhraseQueryBuilder> {
     @Override
     protected MatchPhraseQueryBuilder doCreateTestQueryBuilder() {
-        String fieldName = randomFrom(STRING_FIELD_NAME, BOOLEAN_FIELD_NAME, INT_FIELD_NAME,
-                DOUBLE_FIELD_NAME, DATE_FIELD_NAME);
+        String fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME, BOOLEAN_FIELD_NAME,
+            INT_FIELD_NAME, DOUBLE_FIELD_NAME, DATE_FIELD_NAME);
         if (fieldName.equals(DATE_FIELD_NAME)) {
             assumeTrue("test runs only when at least a type is registered", getCurrentTypes().length > 0);
         }
         Object value;
-        if (fieldName.equals(STRING_FIELD_NAME)) {
+        if (isTextField(fieldName)) {
             int terms = randomIntBetween(0, 3);
             StringBuilder builder = new StringBuilder();
             for (int i = 0; i < terms; i++) {
@@ -64,7 +64,7 @@ public class MatchPhraseQueryBuilderTests extends AbstractQueryTestCase<MatchPhr
 
         MatchPhraseQueryBuilder matchQuery = new MatchPhraseQueryBuilder(fieldName, value);
 
-        if (randomBoolean() && fieldName.equals(STRING_FIELD_NAME)) {
+        if (randomBoolean() && isTextField(fieldName)) {
             matchQuery.analyzer(randomFrom("simple", "keyword", "whitespace"));
         }
 

server/src/test/java/org/elasticsearch/index/query/MatchQueryBuilderTests.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.query;
 
+import org.apache.lucene.index.Term;
 import org.apache.lucene.queries.ExtendedCommonTermsQuery;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
@@ -47,6 +48,7 @@ import org.hamcrest.Matcher;
 
 import java.io.IOException;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 
@@ -59,13 +61,13 @@ import static org.hamcrest.Matchers.notNullValue;
 public class MatchQueryBuilderTests extends AbstractQueryTestCase<MatchQueryBuilder> {
     @Override
     protected MatchQueryBuilder doCreateTestQueryBuilder() {
-        String fieldName = randomFrom(STRING_FIELD_NAME, BOOLEAN_FIELD_NAME, INT_FIELD_NAME,
-                DOUBLE_FIELD_NAME, DATE_FIELD_NAME);
+        String fieldName = STRING_ALIAS_FIELD_NAME; //randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME, BOOLEAN_FIELD_NAME,
+            //INT_FIELD_NAME, DOUBLE_FIELD_NAME, DATE_FIELD_NAME);
         if (fieldName.equals(DATE_FIELD_NAME)) {
             assumeTrue("test runs only when at least a type is registered", getCurrentTypes().length > 0);
         }
         Object value;
-        if (fieldName.equals(STRING_FIELD_NAME)) {
+        if (isTextField(fieldName)) {
             int terms = randomIntBetween(0, 3);
             StringBuilder builder = new StringBuilder();
             for (int i = 0; i < terms; i++) {
@@ -79,11 +81,11 @@ public class MatchQueryBuilderTests extends AbstractQueryTestCase<MatchQueryBuil
         MatchQueryBuilder matchQuery = new MatchQueryBuilder(fieldName, value);
         matchQuery.operator(randomFrom(Operator.values()));
 
-        if (randomBoolean() && fieldName.equals(STRING_FIELD_NAME)) {
+        if (randomBoolean() && isTextField(fieldName)) {
             matchQuery.analyzer(randomFrom("simple", "keyword", "whitespace"));
         }
 
-        if (fieldName.equals(STRING_FIELD_NAME) && randomBoolean()) {
+        if (isTextField(fieldName) && randomBoolean()) {
             matchQuery.fuzziness(randomFuzziness(fieldName));
         }
 
@@ -179,6 +181,12 @@ public class MatchQueryBuilderTests extends AbstractQueryTestCase<MatchQueryBuil
         if (query instanceof ExtendedCommonTermsQuery) {
             assertTrue(queryBuilder.cutoffFrequency() != null);
             ExtendedCommonTermsQuery ectq = (ExtendedCommonTermsQuery) query;
+            List<Term> terms = ectq.getTerms();
+            if (!terms.isEmpty()) {
+                Term term = terms.iterator().next();
+                String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+                assertThat(term.field(), equalTo(expectedFieldName));
+            }
             assertEquals(queryBuilder.cutoffFrequency(), ectq.getMaxTermFrequency(), Float.MIN_VALUE);
         }
 
@@ -195,6 +203,9 @@ public class MatchQueryBuilderTests extends AbstractQueryTestCase<MatchQueryBuil
                 termLcMatcher = either(termLcMatcher).or(equalTo(originalTermLc.substring(0, 1)));
             }
             assertThat(actualTermLc, termLcMatcher);
+
+            String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+            assertThat(expectedFieldName, equalTo(fuzzyQuery.getTerm().field()));
             assertThat(queryBuilder.prefixLength(), equalTo(fuzzyQuery.getPrefixLength()));
             assertThat(queryBuilder.fuzzyTranspositions(), equalTo(fuzzyQuery.getTranspositions()));
         }

server/src/test/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilderTests.java

@@ -91,7 +91,7 @@ public class MoreLikeThisQueryBuilderTests extends AbstractQueryTestCase<MoreLik
     }
 
     private static String[] randomStringFields() {
-        String[] mappedStringFields = new String[]{STRING_FIELD_NAME, STRING_FIELD_NAME_2};
+        String[] mappedStringFields = new String[]{STRING_FIELD_NAME, STRING_FIELD_NAME_2, STRING_ALIAS_FIELD_NAME};
         String[] unmappedStringFields = generateRandomStringArray(2, 5, false, false);
         return Stream.concat(Arrays.stream(mappedStringFields), Arrays.stream(unmappedStringFields)).toArray(String[]::new);
     }

server/src/test/java/org/elasticsearch/index/query/MultiMatchQueryBuilderTests.java

@@ -230,9 +230,10 @@ public class MultiMatchQueryBuilderTests extends AbstractQueryTestCase<MultiMatc
         assertThat(query, instanceOf(DisjunctionMaxQuery.class));
         DisjunctionMaxQuery dQuery = (DisjunctionMaxQuery) query;
         assertThat(dQuery.getTieBreakerMultiplier(), equalTo(1.0f));
-        assertThat(dQuery.getDisjuncts().size(), equalTo(2));
-        assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 0).getTerm(), equalTo(new Term(STRING_FIELD_NAME_2, "test")));
-        assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 1).getTerm(), equalTo(new Term(STRING_FIELD_NAME, "test")));
+        assertThat(dQuery.getDisjuncts().size(), equalTo(3));
+        assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 0).getTerm(), equalTo(new Term(STRING_FIELD_NAME, "test")));
+        assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 1).getTerm(), equalTo(new Term(STRING_FIELD_NAME_2, "test")));
+        assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 2).getTerm(), equalTo(new Term(STRING_FIELD_NAME, "test")));
     }
 
     public void testToQueryFieldMissing() throws Exception {

server/src/test/java/org/elasticsearch/index/query/PrefixQueryBuilderTests.java

@@ -60,7 +60,9 @@ public class PrefixQueryBuilderTests extends AbstractQueryTestCase<PrefixQueryBu
     }
 
     private static PrefixQueryBuilder randomPrefixQuery() {
-        String fieldName = randomBoolean() ? STRING_FIELD_NAME : randomAlphaOfLengthBetween(1, 10);
+        String fieldName = randomFrom(STRING_FIELD_NAME,
+            STRING_ALIAS_FIELD_NAME,
+            randomAlphaOfLengthBetween(1, 10));
         String value = randomAlphaOfLengthBetween(1, 10);
         return new PrefixQueryBuilder(fieldName, value);
     }
@@ -69,7 +71,9 @@ public class PrefixQueryBuilderTests extends AbstractQueryTestCase<PrefixQueryBu
     protected void doAssertLuceneQuery(PrefixQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         assertThat(query, instanceOf(PrefixQuery.class));
         PrefixQuery prefixQuery = (PrefixQuery) query;
-        assertThat(prefixQuery.getPrefix().field(), equalTo(queryBuilder.fieldName()));
+
+        String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+        assertThat(prefixQuery.getPrefix().field(), equalTo(expectedFieldName));
         assertThat(prefixQuery.getPrefix().text(), equalTo(queryBuilder.value()));
     }
 

server/src/test/java/org/elasticsearch/index/query/QueryStringQueryBuilderTests.java

@@ -90,12 +90,16 @@ public class QueryStringQueryBuilderTests extends AbstractQueryTestCase<QueryStr
         }
         QueryStringQueryBuilder queryStringQueryBuilder = new QueryStringQueryBuilder(query);
         if (randomBoolean()) {
-            queryStringQueryBuilder.defaultField(randomBoolean() ?
-                STRING_FIELD_NAME : randomAlphaOfLengthBetween(1, 10));
+            String defaultFieldName = randomFrom(STRING_FIELD_NAME,
+                STRING_ALIAS_FIELD_NAME,
+                randomAlphaOfLengthBetween(1, 10));
+            queryStringQueryBuilder.defaultField(defaultFieldName);
         } else {
             int numFields = randomIntBetween(1, 5);
             for (int i = 0; i < numFields; i++) {
-                String fieldName = randomBoolean() ? STRING_FIELD_NAME : randomAlphaOfLengthBetween(1, 10);
+                String fieldName = randomFrom(STRING_FIELD_NAME,
+                    STRING_ALIAS_FIELD_NAME,
+                    randomAlphaOfLengthBetween(1, 10));
                 if (randomBoolean()) {
                     queryStringQueryBuilder.field(fieldName);
                 } else {
@@ -508,10 +512,12 @@ public class QueryStringQueryBuilderTests extends AbstractQueryTestCase<QueryStr
         Query query = queryStringQuery("test").field("mapped_str*").toQuery(createShardContext());
         assertThat(query, instanceOf(DisjunctionMaxQuery.class));
         DisjunctionMaxQuery dQuery = (DisjunctionMaxQuery) query;
-        assertThat(dQuery.getDisjuncts().size(), equalTo(2));
+        assertThat(dQuery.getDisjuncts().size(), equalTo(3));
         assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 0).getTerm(),
-            equalTo(new Term(STRING_FIELD_NAME_2, "test")));
+            equalTo(new Term(STRING_FIELD_NAME, "test")));
         assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 1).getTerm(),
+            equalTo(new Term(STRING_FIELD_NAME_2, "test")));
+        assertThat(assertDisjunctionSubQuery(query, TermQuery.class, 2).getTerm(),
             equalTo(new Term(STRING_FIELD_NAME, "test")));
     }
 

server/src/test/java/org/elasticsearch/index/query/RandomQueryBuilder.java

@@ -22,10 +22,12 @@ package org.elasticsearch.index.query;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomStrings;
 
-import org.elasticsearch.test.AbstractQueryTestCase;
-
 import java.util.Random;
 
+import static org.elasticsearch.test.AbstractBuilderTestCase.STRING_ALIAS_FIELD_NAME;
+import static org.elasticsearch.test.AbstractBuilderTestCase.STRING_FIELD_NAME;
+import static org.elasticsearch.test.ESTestCase.randomFrom;
+
 /**
  * Utility class for creating random QueryBuilders.
  * So far only leaf queries like {@link MatchAllQueryBuilder}, {@link TermQueryBuilder} or
@@ -62,9 +64,10 @@ public class RandomQueryBuilder {
         // for now, only use String Rangequeries for MultiTerm test, numeric and date makes little sense
         // see issue #12123 for discussion
         MultiTermQueryBuilder multiTermQueryBuilder;
+        String fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME);
         switch(RandomNumbers.randomIntBetween(r, 0, 3)) {
             case 0:
-                RangeQueryBuilder stringRangeQuery = new RangeQueryBuilder(AbstractQueryTestCase.STRING_FIELD_NAME);
+                RangeQueryBuilder stringRangeQuery = new RangeQueryBuilder(fieldName);
                 stringRangeQuery.from("a" + RandomStrings.randomAsciiOfLengthBetween(r, 1, 10));
                 stringRangeQuery.to("z" + RandomStrings.randomAsciiOfLengthBetween(r, 1, 10));
                 multiTermQueryBuilder = stringRangeQuery;
@@ -76,7 +79,7 @@ public class RandomQueryBuilder {
                 multiTermQueryBuilder = new WildcardQueryBuilderTests().createTestQueryBuilder();
                 break;
             case 3:
-                multiTermQueryBuilder = new FuzzyQueryBuilder(AbstractQueryTestCase.STRING_FIELD_NAME,
+                multiTermQueryBuilder = new FuzzyQueryBuilder(fieldName,
                         RandomStrings.randomAsciiOfLengthBetween(r, 1, 10));
                 break;
             default:

server/src/test/java/org/elasticsearch/index/query/RangeQueryBuilderTests.java

@@ -65,13 +65,15 @@ public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuil
         switch (randomIntBetween(0, 2)) {
             case 0:
                 // use mapped integer field for numeric range queries
-                query = new RangeQueryBuilder(randomBoolean() ? INT_FIELD_NAME : INT_RANGE_FIELD_NAME);
+                query = new RangeQueryBuilder(randomFrom(
+                    INT_FIELD_NAME, INT_RANGE_FIELD_NAME, INT_ALIAS_FIELD_NAME));
                 query.from(randomIntBetween(1, 100));
                 query.to(randomIntBetween(101, 200));
                 break;
             case 1:
                 // use mapped date field, using date string representation
-                query = new RangeQueryBuilder(randomBoolean() ? DATE_FIELD_NAME : DATE_RANGE_FIELD_NAME);
+                query = new RangeQueryBuilder(randomFrom(
+                    DATE_FIELD_NAME, DATE_RANGE_FIELD_NAME, DATE_ALIAS_FIELD_NAME));
                 query.from(new DateTime(System.currentTimeMillis() - randomIntBetween(0, 1000000), DateTimeZone.UTC).toString());
                 query.to(new DateTime(System.currentTimeMillis() + randomIntBetween(0, 1000000), DateTimeZone.UTC).toString());
                 // Create timestamp option only then we have a date mapper,
@@ -87,7 +89,7 @@ public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuil
                 break;
             case 2:
             default:
-                query = new RangeQueryBuilder(STRING_FIELD_NAME);
+                query = new RangeQueryBuilder(randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME));
                 query.from("a" + randomAlphaOfLengthBetween(1, 10));
                 query.to("z" + randomAlphaOfLengthBetween(1, 10));
                 break;
@@ -128,17 +130,18 @@ public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuil
 
     @Override
     protected void doAssertLuceneQuery(RangeQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
+        String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
         if (queryBuilder.from() == null && queryBuilder.to() == null) {
             final Query expectedQuery;
             if (getCurrentTypes().length > 0) {
                 if (context.mapperService().getIndexSettings().getIndexVersionCreated().onOrAfter(Version.V_6_1_0)
                         && context.mapperService().fullName(queryBuilder.fieldName()).hasDocValues()) {
-                    expectedQuery = new ConstantScoreQuery(new DocValuesFieldExistsQuery(queryBuilder.fieldName()));
+                    expectedQuery = new ConstantScoreQuery(new DocValuesFieldExistsQuery(expectedFieldName));
                 } else if (context.mapperService().getIndexSettings().getIndexVersionCreated().onOrAfter(Version.V_6_1_0)
                         && context.mapperService().fullName(queryBuilder.fieldName()).omitNorms() == false) {
-                    expectedQuery = new ConstantScoreQuery(new NormsFieldExistsQuery(queryBuilder.fieldName()));
+                    expectedQuery = new ConstantScoreQuery(new NormsFieldExistsQuery(expectedFieldName));
                 } else {
-                    expectedQuery = new ConstantScoreQuery(new TermQuery(new Term(FieldNamesFieldMapper.NAME, queryBuilder.fieldName())));
+                    expectedQuery = new ConstantScoreQuery(new TermQuery(new Term(FieldNamesFieldMapper.NAME, expectedFieldName)));
                 }
             } else {
                 expectedQuery = new MatchNoDocsQuery("no mappings yet");
@@ -146,18 +149,18 @@ public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuil
             assertThat(query, equalTo(expectedQuery));
 
         } else if (getCurrentTypes().length == 0 ||
-            (queryBuilder.fieldName().equals(DATE_FIELD_NAME) == false
-                && queryBuilder.fieldName().equals(INT_FIELD_NAME) == false
-                && queryBuilder.fieldName().equals(DATE_RANGE_FIELD_NAME) == false
-                && queryBuilder.fieldName().equals(INT_RANGE_FIELD_NAME) == false)) {
+            (expectedFieldName.equals(DATE_FIELD_NAME) == false
+                && expectedFieldName.equals(INT_FIELD_NAME) == false
+                && expectedFieldName.equals(DATE_RANGE_FIELD_NAME) == false
+                && expectedFieldName.equals(INT_RANGE_FIELD_NAME) == false)) {
             assertThat(query, instanceOf(TermRangeQuery.class));
             TermRangeQuery termRangeQuery = (TermRangeQuery) query;
-            assertThat(termRangeQuery.getField(), equalTo(queryBuilder.fieldName()));
+            assertThat(termRangeQuery.getField(), equalTo(expectedFieldName));
             assertThat(termRangeQuery.getLowerTerm(), equalTo(BytesRefs.toBytesRef(queryBuilder.from())));
             assertThat(termRangeQuery.getUpperTerm(), equalTo(BytesRefs.toBytesRef(queryBuilder.to())));
             assertThat(termRangeQuery.includesLower(), equalTo(queryBuilder.includeLower()));
             assertThat(termRangeQuery.includesUpper(), equalTo(queryBuilder.includeUpper()));
-        } else if (queryBuilder.fieldName().equals(DATE_FIELD_NAME)) {
+        } else if (expectedFieldName.equals(DATE_FIELD_NAME)) {
             assertThat(query, instanceOf(IndexOrDocValuesQuery.class));
             query = ((IndexOrDocValuesQuery) query).getIndexQuery();
             assertThat(query, instanceOf(PointRangeQuery.class));
@@ -202,7 +205,7 @@ public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuil
                 }
             }
             assertEquals(LongPoint.newRangeQuery(DATE_FIELD_NAME, minLong, maxLong), query);
-        } else if (queryBuilder.fieldName().equals(INT_FIELD_NAME)) {
+        } else if (expectedFieldName.equals(INT_FIELD_NAME)) {
             assertThat(query, instanceOf(IndexOrDocValuesQuery.class));
             query = ((IndexOrDocValuesQuery) query).getIndexQuery();
             assertThat(query, instanceOf(PointRangeQuery.class));
@@ -225,7 +228,7 @@ public class RangeQueryBuilderTests extends AbstractQueryTestCase<RangeQueryBuil
                     maxInt--;
                 }
             }
-        } else if (queryBuilder.fieldName().equals(DATE_RANGE_FIELD_NAME) || queryBuilder.fieldName().equals(INT_RANGE_FIELD_NAME)) {
+        } else if (expectedFieldName.equals(DATE_RANGE_FIELD_NAME) || expectedFieldName.equals(INT_RANGE_FIELD_NAME)) {
             // todo can't check RangeFieldQuery because its currently package private (this will change)
         } else {
             throw new UnsupportedOperationException();

server/src/test/java/org/elasticsearch/index/query/RegexpQueryBuilderTests.java

@@ -71,7 +71,7 @@ public class RegexpQueryBuilderTests extends AbstractQueryTestCase<RegexpQueryBu
 
     private static RegexpQueryBuilder randomRegexpQuery() {
         // mapped or unmapped fields
-        String fieldName = randomBoolean() ? STRING_FIELD_NAME : randomAlphaOfLengthBetween(1, 10);
+        String fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME, randomAlphaOfLengthBetween(1, 10));
         String value = randomAlphaOfLengthBetween(1, 10);
         return new RegexpQueryBuilder(fieldName, value);
     }
@@ -80,7 +80,9 @@ public class RegexpQueryBuilderTests extends AbstractQueryTestCase<RegexpQueryBu
     protected void doAssertLuceneQuery(RegexpQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         assertThat(query, instanceOf(RegexpQuery.class));
         RegexpQuery regexpQuery = (RegexpQuery) query;
-        assertThat(regexpQuery.getField(), equalTo(queryBuilder.fieldName()));
+
+        String expectedFieldName = expectedFieldName( queryBuilder.fieldName());
+        assertThat(regexpQuery.getField(), equalTo(expectedFieldName));
     }
 
     public void testIllegalArguments() {

server/src/test/java/org/elasticsearch/index/query/SimpleQueryStringBuilderTests.java

@@ -98,7 +98,8 @@ public class SimpleQueryStringBuilderTests extends AbstractQueryTestCase<SimpleQ
         Map<String, Float> fields = new HashMap<>();
         for (int i = 0; i < fieldCount; i++) {
             if (randomBoolean()) {
-                fields.put(STRING_FIELD_NAME, AbstractQueryBuilder.DEFAULT_BOOST);
+                String fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME);
+                fields.put(fieldName, AbstractQueryBuilder.DEFAULT_BOOST);
             } else {
                 fields.put(STRING_FIELD_NAME_2, 2.0f / randomIntBetween(1, 20));
             }

server/src/test/java/org/elasticsearch/index/query/SpanMultiTermQueryBuilderTests.java

@@ -63,7 +63,11 @@ public class SpanMultiTermQueryBuilderTests extends AbstractQueryTestCase<SpanMu
                 .field("type", "text")
                 .startObject("index_prefixes").endObject()
             .endObject()
-            .endObject().endObject().endObject();
+            .startObject("prefix_field_alias")
+                .field("type", "alias")
+                .field("path", "prefix_field")
+            .endObject()
+        .endObject().endObject().endObject();
 
         mapperService.merge("_doc",
             new CompressedXContent(Strings.toString(mapping)), MapperService.MergeReason.MAPPING_UPDATE);
@@ -168,16 +172,16 @@ public class SpanMultiTermQueryBuilderTests extends AbstractQueryTestCase<SpanMu
     }
 
     public void testToQueryInnerSpanMultiTerm() throws IOException {
-
         Query query = new SpanOrQueryBuilder(createTestQueryBuilder()).toQuery(createShardContext());
         //verify that the result is still a span query, despite the boost that might get set (SpanBoostQuery rather than BoostQuery)
         assertThat(query, instanceOf(SpanQuery.class));
     }
 
     public void testToQueryInnerTermQuery() throws IOException {
+        String fieldName = randomFrom("prefix_field", "prefix_field_alias");
         final QueryShardContext context = createShardContext();
         if (context.getIndexSettings().getIndexVersionCreated().onOrAfter(Version.V_6_4_0)) {
-            Query query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder("prefix_field", "foo"))
+            Query query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder(fieldName, "foo"))
                 .toQuery(context);
             assertThat(query, instanceOf(FieldMaskingSpanQuery.class));
             FieldMaskingSpanQuery fieldSpanQuery = (FieldMaskingSpanQuery) query;
@@ -186,7 +190,7 @@ public class SpanMultiTermQueryBuilderTests extends AbstractQueryTestCase<SpanMu
             SpanTermQuery spanTermQuery = (SpanTermQuery) fieldSpanQuery.getMaskedQuery();
             assertThat(spanTermQuery.getTerm().text(), equalTo("foo"));
 
-            query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder("prefix_field", "foo"))
+            query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder(fieldName, "foo"))
                 .boost(2.0f)
                 .toQuery(context);
             assertThat(query, instanceOf(SpanBoostQuery.class));
@@ -199,7 +203,7 @@ public class SpanMultiTermQueryBuilderTests extends AbstractQueryTestCase<SpanMu
             spanTermQuery = (SpanTermQuery) fieldSpanQuery.getMaskedQuery();
             assertThat(spanTermQuery.getTerm().text(), equalTo("foo"));
         } else {
-            Query query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder("prefix_field", "foo"))
+            Query query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder(fieldName, "foo"))
                 .toQuery(context);
             assertThat(query, instanceOf(SpanMultiTermQueryWrapper.class));
             SpanMultiTermQueryWrapper wrapper = (SpanMultiTermQueryWrapper) query;
@@ -208,7 +212,7 @@ public class SpanMultiTermQueryBuilderTests extends AbstractQueryTestCase<SpanMu
             assertThat(prefixQuery.getField(), equalTo("prefix_field"));
             assertThat(prefixQuery.getPrefix().text(), equalTo("foo"));
 
-            query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder("prefix_field", "foo"))
+            query = new SpanMultiTermQueryBuilder(new PrefixQueryBuilder(fieldName, "foo"))
                 .boost(2.0f)
                 .toQuery(context);
             assertThat(query, instanceOf(SpanBoostQuery.class));

server/src/test/java/org/elasticsearch/index/query/SpanTermQueryBuilderTests.java

@@ -38,12 +38,11 @@ public class SpanTermQueryBuilderTests extends AbstractTermQueryTestCase<SpanTer
 
     @Override
     protected SpanTermQueryBuilder doCreateTestQueryBuilder() {
-        String fieldName = null;
-        Object value;
+        String fieldName = randomFrom(STRING_FIELD_NAME,
+            STRING_ALIAS_FIELD_NAME,
+            randomAlphaOfLengthBetween(1, 10));
 
-        if (randomBoolean()) {
-            fieldName = STRING_FIELD_NAME;
-        }
+        Object value;
         if (frequently()) {
             value = randomAlphaOfLengthBetween(1, 10);
         } else {
@@ -51,10 +50,6 @@ public class SpanTermQueryBuilderTests extends AbstractTermQueryTestCase<SpanTer
             JsonStringEncoder encoder = JsonStringEncoder.getInstance();
             value = new String(encoder.quoteAsString(randomUnicodeOfLength(10)));
         }
-
-        if (fieldName == null) {
-            fieldName = randomAlphaOfLengthBetween(1, 10);
-        }
         return createQueryBuilder(fieldName, value);
     }
 
@@ -67,7 +62,10 @@ public class SpanTermQueryBuilderTests extends AbstractTermQueryTestCase<SpanTer
     protected void doAssertLuceneQuery(SpanTermQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         assertThat(query, instanceOf(SpanTermQuery.class));
         SpanTermQuery spanTermQuery = (SpanTermQuery) query;
-        assertThat(spanTermQuery.getTerm().field(), equalTo(queryBuilder.fieldName()));
+
+        String expectedFieldName = expectedFieldName(queryBuilder.fieldName);
+        assertThat(spanTermQuery.getTerm().field(), equalTo(expectedFieldName));
+
         MappedFieldType mapper = context.getQueryShardContext().fieldMapper(queryBuilder.fieldName());
         if (mapper != null) {
             Term term = ((TermQuery) mapper.termQuery(queryBuilder.value(), null)).getTerm();

server/src/test/java/org/elasticsearch/index/query/TermQueryBuilderTests.java

@@ -50,7 +50,7 @@ public class TermQueryBuilderTests extends AbstractTermQueryTestCase<TermQueryBu
                 break;
             case 1:
                 if (randomBoolean()) {
-                    fieldName = STRING_FIELD_NAME;
+                    fieldName = randomFrom(STRING_FIELD_NAME, STRING_ALIAS_FIELD_NAME);
                 }
                 if (frequently()) {
                     value = randomAlphaOfLengthBetween(1, 10);
@@ -96,7 +96,10 @@ public class TermQueryBuilderTests extends AbstractTermQueryTestCase<TermQueryBu
         MappedFieldType mapper = context.getQueryShardContext().fieldMapper(queryBuilder.fieldName());
         if (query instanceof TermQuery) {
             TermQuery termQuery = (TermQuery) query;
-            assertThat(termQuery.getTerm().field(), equalTo(queryBuilder.fieldName()));
+
+            String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+            assertThat(termQuery.getTerm().field(), equalTo(expectedFieldName));
+
             if (mapper != null) {
                 Term term = ((TermQuery) mapper.termQuery(queryBuilder.value(), null)).getTerm();
                 assertThat(termQuery.getTerm(), equalTo(term));

server/src/test/java/org/elasticsearch/index/query/TermsQueryBuilderTests.java

@@ -77,9 +77,13 @@ public class TermsQueryBuilderTests extends AbstractQueryTestCase<TermsQueryBuil
         // terms query or lookup query
         if (randomBoolean()) {
             // make between 0 and 5 different values of the same type
-            String fieldName;
-            fieldName = randomValueOtherThanMany(choice -> choice.equals(GEO_POINT_FIELD_NAME) || choice.equals(GEO_SHAPE_FIELD_NAME)
-                    || choice.equals(INT_RANGE_FIELD_NAME) || choice.equals(DATE_RANGE_FIELD_NAME), () -> getRandomFieldName());
+            String fieldName = randomValueOtherThanMany(choice ->
+                    choice.equals(GEO_POINT_FIELD_NAME) ||
+                    choice.equals(GEO_POINT_ALIAS_FIELD_NAME) ||
+                    choice.equals(GEO_SHAPE_FIELD_NAME) ||
+                    choice.equals(INT_RANGE_FIELD_NAME) ||
+                    choice.equals(DATE_RANGE_FIELD_NAME),
+                () -> getRandomFieldName());
             Object[] values = new Object[randomInt(5)];
             for (int i = 0; i < values.length; i++) {
                 values[i] = getRandomValueForFieldName(fieldName);
@@ -129,7 +133,8 @@ public class TermsQueryBuilderTests extends AbstractQueryTestCase<TermsQueryBuil
                 terms = queryBuilder.values();
             }
 
-            TermInSetQuery expected = new TermInSetQuery(queryBuilder.fieldName(),
+            String fieldName = expectedFieldName(queryBuilder.fieldName());
+            TermInSetQuery expected = new TermInSetQuery(fieldName,
                     terms.stream().filter(Objects::nonNull).map(Object::toString).map(BytesRef::new).collect(Collectors.toList()));
             assertEquals(expected, query);
         }

server/src/test/java/org/elasticsearch/index/query/TermsSetQueryBuilderTests.java

@@ -28,12 +28,14 @@ import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.NoMergePolicy;
+import org.apache.lucene.index.Term;
 import org.apache.lucene.search.CoveringQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
+import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
@@ -83,10 +85,9 @@ public class TermsSetQueryBuilderTests extends AbstractQueryTestCase<TermsSetQue
 
     @Override
     protected TermsSetQueryBuilder doCreateTestQueryBuilder() {
-        String fieldName;
-        do {
-            fieldName = randomFrom(MAPPED_FIELD_NAMES);
-        } while (fieldName.equals(GEO_POINT_FIELD_NAME) || fieldName.equals(GEO_SHAPE_FIELD_NAME));
+        String fieldName = randomValueOtherThanMany(
+            value -> value.equals(GEO_POINT_FIELD_NAME) || value.equals(GEO_SHAPE_FIELD_NAME),
+            () -> randomFrom(MAPPED_FIELD_NAMES));
         List<?> randomTerms = randomValues(fieldName);
         TermsSetQueryBuilder queryBuilder = new TermsSetQueryBuilder(STRING_FIELD_NAME, randomTerms);
         if (randomBoolean()) {
@@ -261,6 +262,22 @@ public class TermsSetQueryBuilderTests extends AbstractQueryTestCase<TermsSetQue
         }
     }
 
+    public void testFieldAlias() {
+        List<String> randomTerms = Arrays.asList(generateRandomStringArray(5, 10, false, false));
+        TermsSetQueryBuilder queryBuilder = new TermsSetQueryBuilder(STRING_ALIAS_FIELD_NAME, randomTerms)
+            .setMinimumShouldMatchField("m_s_m");
+
+        QueryShardContext context = createShardContext();
+        List<Query> termQueries = queryBuilder.createTermQueries(context);
+        assertEquals(randomTerms.size(), termQueries.size());
+
+        String expectedFieldName = expectedFieldName(queryBuilder.getFieldName());
+        for (int i = 0; i < randomTerms.size(); i++) {
+            Term term = new Term(expectedFieldName, randomTerms.get(i));
+            assertThat(termQueries.get(i), equalTo(new TermQuery(term)));
+        }
+    }
+
     private static List<?> randomValues(final String fieldName) {
         final int numValues = randomIntBetween(0, 10);
         final List<Object> values = new ArrayList<>(numValues);

server/src/test/java/org/elasticsearch/index/query/WildcardQueryBuilderTests.java

@@ -60,21 +60,22 @@ public class WildcardQueryBuilderTests extends AbstractQueryTestCase<WildcardQue
     }
 
     private static WildcardQueryBuilder randomWildcardQuery() {
-        // mapped or unmapped field
+        String fieldName = randomFrom(STRING_FIELD_NAME,
+            STRING_ALIAS_FIELD_NAME,
+            randomAlphaOfLengthBetween(1, 10));
         String text = randomAlphaOfLengthBetween(1, 10);
-        if (randomBoolean()) {
-            return new WildcardQueryBuilder(STRING_FIELD_NAME, text);
-        } else {
-            return new WildcardQueryBuilder(randomAlphaOfLengthBetween(1, 10), text);
-        }
+
+        return new WildcardQueryBuilder(fieldName, text);
     }
 
     @Override
     protected void doAssertLuceneQuery(WildcardQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         assertThat(query, instanceOf(WildcardQuery.class));
         WildcardQuery wildcardQuery = (WildcardQuery) query;
-        assertThat(wildcardQuery.getField(), equalTo(queryBuilder.fieldName()));
-        assertThat(wildcardQuery.getTerm().field(), equalTo(queryBuilder.fieldName()));
+
+        String expectedFieldName = expectedFieldName(queryBuilder.fieldName());
+        assertThat(wildcardQuery.getField(), equalTo(expectedFieldName));
+        assertThat(wildcardQuery.getTerm().field(), equalTo(expectedFieldName));
         assertThat(wildcardQuery.getTerm().text(), equalTo(queryBuilder.value()));
     }
 
@@ -138,19 +139,19 @@ public class WildcardQueryBuilderTests extends AbstractQueryTestCase<WildcardQue
             assertEquals(expected, query);
         }
     }
-    
+
     public void testIndexWildcard() throws IOException {
         assumeTrue("test runs only when at least a type is registered", getCurrentTypes().length > 0);
 
         QueryShardContext context = createShardContext();
         String index = context.getFullyQualifiedIndexName();
-        
+
         Query query = new WildcardQueryBuilder("_index", index).doToQuery(context);
         assertThat(query instanceof MatchAllDocsQuery, equalTo(true));
-        
+
         query = new WildcardQueryBuilder("_index", index + "*").doToQuery(context);
         assertThat(query instanceof MatchAllDocsQuery, equalTo(true));
-        
+
         query = new WildcardQueryBuilder("_index", "index_" + index + "*").doToQuery(context);
         assertThat(query instanceof MatchNoDocsQuery, equalTo(true));
     }

server/src/test/java/org/elasticsearch/index/similarity/SimilarityTests.java

@@ -38,11 +38,12 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.index.IndexService;
-import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.MapperParsingException;
+import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 import org.elasticsearch.test.InternalSettingsPlugin;
@@ -86,22 +87,21 @@ public class SimilarityTests extends ESSingleNodeTestCase {
     }
 
     public void testResolveSimilaritiesFromMapping_classic() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "classic")
             .put("index.similarity.my_similarity.discount_overlaps", false)
             .put(IndexMetaData.SETTING_VERSION_CREATED, Version.V_6_3_0) // otherwise classic is forbidden
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(), instanceOf(ClassicSimilarity.class));
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(ClassicSimilarity.class));
 
-        ClassicSimilarity similarity = (ClassicSimilarity) documentMapper.mappers().getMapper("field1").fieldType().similarity().get();
+        ClassicSimilarity similarity = (ClassicSimilarity) mapperService.fullName("field1").similarity().get();
         assertThat(similarity.getDiscountOverlaps(), equalTo(false));
     }
 
@@ -117,11 +117,11 @@ public class SimilarityTests extends ESSingleNodeTestCase {
     }
 
     public void testResolveSimilaritiesFromMapping_bm25() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "BM25")
@@ -129,37 +129,32 @@ public class SimilarityTests extends ESSingleNodeTestCase {
             .put("index.similarity.my_similarity.b", 0.5f)
             .put("index.similarity.my_similarity.discount_overlaps", false)
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(), instanceOf(BM25Similarity.class));
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(BM25Similarity.class));
 
-        BM25Similarity similarity = (BM25Similarity) documentMapper.mappers().getMapper("field1").fieldType().similarity().get();
+        BM25Similarity similarity = (BM25Similarity) mapperService.fullName("field1").similarity().get();
         assertThat(similarity.getK1(), equalTo(2.0f));
         assertThat(similarity.getB(), equalTo(0.5f));
         assertThat(similarity.getDiscountOverlaps(), equalTo(false));
     }
 
     public void testResolveSimilaritiesFromMapping_boolean() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "boolean").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
-        IndexService indexService = createIndex("foo", Settings.EMPTY);
-        DocumentMapper documentMapper = indexService.mapperService()
-            .documentMapperParser()
-            .parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(),
-            instanceOf(BooleanSimilarity.class));
+        MapperService mapperService = createIndex("foo", Settings.EMPTY, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(BooleanSimilarity.class));
     }
 
     public void testResolveSimilaritiesFromMapping_DFR() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "DFR")
@@ -168,11 +163,10 @@ public class SimilarityTests extends ESSingleNodeTestCase {
             .put("index.similarity.my_similarity.normalization", "h2")
             .put("index.similarity.my_similarity.normalization.h2.c", 3f)
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(), instanceOf(DFRSimilarity.class));
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(DFRSimilarity.class));
 
-        DFRSimilarity similarity = (DFRSimilarity) documentMapper.mappers().getMapper("field1").fieldType().similarity().get();
+        DFRSimilarity similarity = (DFRSimilarity) mapperService.fullName("field1").similarity().get();
         assertThat(similarity.getBasicModel(), instanceOf(BasicModelG.class));
         assertThat(similarity.getAfterEffect(), instanceOf(AfterEffectL.class));
         assertThat(similarity.getNormalization(), instanceOf(NormalizationH2.class));
@@ -180,11 +174,11 @@ public class SimilarityTests extends ESSingleNodeTestCase {
     }
 
     public void testResolveSimilaritiesFromMapping_IB() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "IB")
@@ -193,11 +187,10 @@ public class SimilarityTests extends ESSingleNodeTestCase {
             .put("index.similarity.my_similarity.normalization", "h2")
             .put("index.similarity.my_similarity.normalization.h2.c", 3f)
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(), instanceOf(IBSimilarity.class));
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(IBSimilarity.class));
 
-        IBSimilarity similarity = (IBSimilarity) documentMapper.mappers().getMapper("field1").fieldType().similarity().get();
+        IBSimilarity similarity = (IBSimilarity) mapperService.fullName("field1").similarity().get();
         assertThat(similarity.getDistribution(), instanceOf(DistributionSPL.class));
         assertThat(similarity.getLambda(), instanceOf(LambdaTTF.class));
         assertThat(similarity.getNormalization(), instanceOf(NormalizationH2.class));
@@ -205,59 +198,58 @@ public class SimilarityTests extends ESSingleNodeTestCase {
     }
 
     public void testResolveSimilaritiesFromMapping_DFI() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "DFI")
             .put("index.similarity.my_similarity.independence_measure", "chisquared")
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        MappedFieldType fieldType = documentMapper.mappers().getMapper("field1").fieldType();
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        MappedFieldType fieldType = mapperService.fullName("field1");
+
         assertThat(fieldType.similarity().get(), instanceOf(DFISimilarity.class));
         DFISimilarity similarity = (DFISimilarity) fieldType.similarity().get();
         assertThat(similarity.getIndependence(), instanceOf(IndependenceChiSquared.class));
     }
 
     public void testResolveSimilaritiesFromMapping_LMDirichlet() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "LMDirichlet")
             .put("index.similarity.my_similarity.mu", 3000f)
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(), instanceOf(LMDirichletSimilarity.class));
 
-        LMDirichletSimilarity similarity = (LMDirichletSimilarity) documentMapper.mappers().getMapper("field1").fieldType().similarity().get();
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(LMDirichletSimilarity.class));
+
+        LMDirichletSimilarity similarity = (LMDirichletSimilarity) mapperService.fullName("field1").similarity().get();
         assertThat(similarity.getMu(), equalTo(3000f));
     }
 
     public void testResolveSimilaritiesFromMapping_LMJelinekMercer() throws IOException {
-        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")
+        XContentBuilder mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
             .startObject("properties")
             .startObject("field1").field("type", "text").field("similarity", "my_similarity").endObject()
             .endObject()
-            .endObject().endObject());
+            .endObject().endObject();
 
         Settings indexSettings = Settings.builder()
             .put("index.similarity.my_similarity.type", "LMJelinekMercer")
             .put("index.similarity.my_similarity.lambda", 0.7f)
             .build();
-        IndexService indexService = createIndex("foo", indexSettings);
-        DocumentMapper documentMapper = indexService.mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
-        assertThat(documentMapper.mappers().getMapper("field1").fieldType().similarity().get(), instanceOf(LMJelinekMercerSimilarity.class));
+        MapperService mapperService = createIndex("foo", indexSettings, "type", mapping).mapperService();
+        assertThat(mapperService.fullName("field1").similarity().get(), instanceOf(LMJelinekMercerSimilarity.class));
 
-        LMJelinekMercerSimilarity similarity = (LMJelinekMercerSimilarity) documentMapper.mappers().getMapper("field1").fieldType().similarity().get();
+        LMJelinekMercerSimilarity similarity = (LMJelinekMercerSimilarity) mapperService.fullName("field1").similarity().get();
         assertThat(similarity.getLambda(), equalTo(0.7f));
     }
 

server/src/test/java/org/elasticsearch/indices/mapping/SimpleGetFieldMappingsIT.java

@@ -20,6 +20,7 @@
 package org.elasticsearch.indices.mapping;
 
 import org.elasticsearch.action.admin.indices.mapping.get.GetFieldMappingsResponse;
+import org.elasticsearch.action.admin.indices.mapping.get.GetFieldMappingsResponse.FieldMappingMetaData;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -68,10 +69,26 @@ public class SimpleGetFieldMappingsIT extends ESIntegTestCase {
     }
 
     private XContentBuilder getMappingForType(String type) throws IOException {
-        return jsonBuilder().startObject().startObject(type).startObject("properties")
-                .startObject("field1").field("type", "text").endObject()
-                .startObject("obj").startObject("properties").startObject("subfield").field("type", "keyword").endObject().endObject().endObject()
-                .endObject().endObject().endObject();
+        return jsonBuilder().startObject()
+            .startObject(type)
+                .startObject("properties")
+                    .startObject("field1")
+                        .field("type", "text")
+                    .endObject()
+                   .startObject("alias")
+                        .field("type", "alias")
+                        .field("path", "field1")
+                    .endObject()
+                    .startObject("obj")
+                        .startObject("properties")
+                            .startObject("subfield")
+                                .field("type", "keyword")
+                            .endObject()
+                        .endObject()
+                    .endObject()
+                .endObject()
+            .endObject()
+        .endObject();
     }
 
     public void testGetFieldMappings() throws Exception {
@@ -138,8 +155,23 @@ public class SimpleGetFieldMappingsIT extends ESIntegTestCase {
         assertThat((Map<String, Object>) response.fieldMappings("test", "type", "field1").sourceAsMap().get("field1"), hasEntry("index", Boolean.TRUE));
         assertThat((Map<String, Object>) response.fieldMappings("test", "type", "field1").sourceAsMap().get("field1"), hasEntry("type", (Object) "text"));
         assertThat((Map<String, Object>) response.fieldMappings("test", "type", "obj.subfield").sourceAsMap().get("subfield"), hasEntry("type", (Object) "keyword"));
+    }
 
+    @SuppressWarnings("unchecked")
+    public void testGetFieldMappingsWithFieldAlias() throws Exception {
+        assertAcked(prepareCreate("test").addMapping("type", getMappingForType("type")));
 
+        GetFieldMappingsResponse response = client().admin().indices().prepareGetFieldMappings()
+            .setFields("alias", "field1").get();
+
+        FieldMappingMetaData aliasMapping = response.fieldMappings("test", "type", "alias");
+        assertThat(aliasMapping.fullName(), equalTo("alias"));
+        assertThat(aliasMapping.sourceAsMap(), hasKey("alias"));
+        assertThat((Map<String, Object>) aliasMapping.sourceAsMap().get("alias"), hasEntry("type", "alias"));
+
+        FieldMappingMetaData field1Mapping = response.fieldMappings("test", "type", "field1");
+        assertThat(field1Mapping.fullName(), equalTo("field1"));
+        assertThat(field1Mapping.sourceAsMap(), hasKey("field1"));
     }
 
     //fix #6552

server/src/test/java/org/elasticsearch/search/aggregations/bucket/RangeIT.java

@@ -116,6 +116,21 @@ public class RangeIT extends ESIntegTestCase {
                     .field(SINGLE_VALUED_FIELD_NAME, i * 2 - 1)
                     .endObject()));
         }
+
+        // Create two indices and add the field 'route_length_miles' as an alias in
+        // one, and a concrete field in the other.
+        prepareCreate("old_index")
+            .addMapping("_doc", "distance", "type=double", "route_length_miles", "type=alias,path=distance")
+            .get();
+        prepareCreate("new_index")
+            .addMapping("_doc", "route_length_miles", "type=double")
+            .get();
+
+        builders.add(client().prepareIndex("old_index", "_doc").setSource("distance", 42.0));
+        builders.add(client().prepareIndex("old_index", "_doc").setSource("distance", 50.5));
+        builders.add(client().prepareIndex("new_index", "_doc").setSource("route_length_miles", 100.2));
+        builders.add(client().prepareIndex("new_index", "_doc").setSource(Collections.emptyMap()));
+
         indexRandom(true, builders);
         ensureSearchable();
     }
@@ -972,4 +987,72 @@ public class RangeIT extends ESIntegTestCase {
         assertThat(client().admin().indices().prepareStats("cache_test_idx").setRequestCache(true).get().getTotal().getRequestCache()
                 .getMissCount(), equalTo(1L));
     }
+
+    public void testFieldAlias() {
+        SearchResponse response = client().prepareSearch("old_index", "new_index")
+            .addAggregation(range("range")
+                .field("route_length_miles")
+                .addUnboundedTo(50.0)
+                .addRange(50.0, 150.0)
+                .addUnboundedFrom(150.0))
+            .execute().actionGet();
+
+        assertSearchResponse(response);
+
+        Range range = response.getAggregations().get("range");
+        assertThat(range, notNullValue());
+        assertThat(range.getName(), equalTo("range"));
+        List<? extends Range.Bucket> buckets = range.getBuckets();
+        assertThat(buckets.size(), equalTo(3));
+
+        Range.Bucket bucket = buckets.get(0);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("*-50.0"));
+        assertThat(bucket.getDocCount(), equalTo(1L));
+
+        bucket = buckets.get(1);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("50.0-150.0"));
+        assertThat(bucket.getDocCount(), equalTo(2L));
+
+        bucket = buckets.get(2);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("150.0-*"));
+        assertThat(bucket.getDocCount(), equalTo(0L));
+    }
+
+
+    public void testFieldAliasWithMissingValue() {
+        SearchResponse response = client().prepareSearch("old_index", "new_index")
+            .addAggregation(range("range")
+                .field("route_length_miles")
+                .missing(0.0)
+                .addUnboundedTo(50.0)
+                .addRange(50.0, 150.0)
+                .addUnboundedFrom(150.0))
+            .execute().actionGet();
+
+        assertSearchResponse(response);
+
+        Range range = response.getAggregations().get("range");
+        assertThat(range, notNullValue());
+        assertThat(range.getName(), equalTo("range"));
+        List<? extends Range.Bucket> buckets = range.getBuckets();
+        assertThat(buckets.size(), equalTo(3));
+
+        Range.Bucket bucket = buckets.get(0);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("*-50.0"));
+        assertThat(bucket.getDocCount(), equalTo(2L));
+
+        bucket = buckets.get(1);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("50.0-150.0"));
+        assertThat(bucket.getDocCount(), equalTo(2L));
+
+        bucket = buckets.get(2);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("150.0-*"));
+        assertThat(bucket.getDocCount(), equalTo(0L));
+    }
 }

server/src/test/java/org/elasticsearch/search/aggregations/bucket/ReverseNestedIT.java

@@ -66,6 +66,10 @@ public class ReverseNestedIT extends ESIntegTestCase {
                         "type",
                         jsonBuilder().startObject().startObject("properties")
                                 .startObject("field1").field("type", "keyword").endObject()
+                                .startObject("alias")
+                                    .field("type", "alias")
+                                    .field("path", "field1")
+                                .endObject()
                                 .startObject("nested1").field("type", "nested").startObject("properties")
                                     .startObject("field2").field("type", "keyword").endObject()
                                 .endObject().endObject()
@@ -649,4 +653,28 @@ public class ReverseNestedIT extends ESIntegTestCase {
             assertThat(barCount.getValue(), equalTo(2L));
         }
     }
+
+    public void testFieldAlias() {
+        SearchResponse response = client().prepareSearch("idx1")
+            .addAggregation(nested("nested1", "nested1")
+                .subAggregation(
+                    terms("field2").field("nested1.field2")
+                        .subAggregation(
+                            reverseNested("nested1_to_field1")
+                                .subAggregation(
+                                    terms("field1").field("alias")
+                                        .collectMode(randomFrom(SubAggCollectionMode.values())))))).get();
+
+        assertSearchResponse(response);
+
+        Nested nested = response.getAggregations().get("nested1");
+        Terms nestedTerms = nested.getAggregations().get("field2");
+        Terms.Bucket bucket = nestedTerms.getBuckets().iterator().next();
+
+        ReverseNested reverseNested = bucket.getAggregations().get("nested1_to_field1");
+        Terms reverseNestedTerms = reverseNested.getAggregations().get("field1");
+
+        assertThat(((InternalAggregation)reverseNested).getProperty("field1"), sameInstance(reverseNestedTerms));
+        assertThat(reverseNestedTerms.getBuckets().size(), equalTo(6));
+    }
 }

server/src/test/java/org/elasticsearch/search/aggregations/bucket/nested/NestedAggregatorTests.java

@@ -71,8 +71,14 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import java.util.stream.DoubleStream;
 
+import static org.elasticsearch.search.aggregations.AggregationBuilders.max;
+import static org.elasticsearch.search.aggregations.AggregationBuilders.nested;
+
 public class NestedAggregatorTests extends AggregatorTestCase {
 
     private static final String VALUE_FIELD_NAME = "number";
@@ -84,6 +90,15 @@ public class NestedAggregatorTests extends AggregatorTestCase {
 
     private final SeqNoFieldMapper.SequenceIDFields sequenceIDFields = SeqNoFieldMapper.SequenceIDFields.emptySeqID();
 
+    /**
+     * For each provided field type, we also register an alias with name <field>-alias.
+     */
+    @Override
+    protected Map<String, MappedFieldType> getFieldAliases(MappedFieldType... fieldTypes) {
+        return Arrays.stream(fieldTypes).collect(Collectors.toMap(
+            ft -> ft.name() + "-alias",
+            Function.identity()));
+    }
 
     public void testNoDocs() throws IOException {
         try (Directory directory = newDirectory()) {
@@ -638,6 +653,49 @@ public class NestedAggregatorTests extends AggregatorTestCase {
         }
     }
 
+    public void testFieldAlias() throws IOException {
+        int numRootDocs = randomIntBetween(1, 20);
+
+        MappedFieldType fieldType = new NumberFieldMapper.NumberFieldType(
+            NumberFieldMapper.NumberType.LONG);
+        fieldType.setName(VALUE_FIELD_NAME);
+
+        try (Directory directory = newDirectory()) {
+            try (RandomIndexWriter iw = new RandomIndexWriter(random(), directory)) {
+                for (int i = 0; i < numRootDocs; i++) {
+                    List<Document> documents = new ArrayList<>();
+                    int numNestedDocs = randomIntBetween(0, 20);
+                    generateDocuments(documents, numNestedDocs, i, NESTED_OBJECT, VALUE_FIELD_NAME);
+
+                    Document document = new Document();
+                    document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(i)), IdFieldMapper.Defaults.FIELD_TYPE));
+                    document.add(new Field(TypeFieldMapper.NAME, "test",
+                        TypeFieldMapper.Defaults.FIELD_TYPE));
+                    document.add(sequenceIDFields.primaryTerm);
+                    documents.add(document);
+                    iw.addDocuments(documents);
+                }
+                iw.commit();
+            }
+
+            try (IndexReader indexReader = wrap(DirectoryReader.open(directory))) {
+                NestedAggregationBuilder agg = nested(NESTED_AGG, NESTED_OBJECT).subAggregation(
+                    max(MAX_AGG_NAME).field(VALUE_FIELD_NAME));
+
+                NestedAggregationBuilder aliasAgg = nested(NESTED_AGG, NESTED_OBJECT).subAggregation(
+                    max(MAX_AGG_NAME).field(VALUE_FIELD_NAME + "-alias"));
+
+                Nested nested = search(newSearcher(indexReader, false, true),
+                    new MatchAllDocsQuery(), agg, fieldType);
+                Nested aliasNested = search(newSearcher(indexReader, false, true),
+                    new MatchAllDocsQuery(), aliasAgg, fieldType);
+
+                assertTrue(nested.getDocCount() > 0);
+                assertEquals(nested, aliasNested);
+            }
+        }
+    }
+
     private double generateMaxDocs(List<Document> documents, int numNestedDocs, int id, String path, String fieldName) {
         return DoubleStream.of(generateDocuments(documents, numNestedDocs, id, path, fieldName))
             .max().orElse(Double.NEGATIVE_INFINITY);

server/src/test/java/org/elasticsearch/search/aggregations/bucket/nested/ReverseNestedAggregatorTests.java

@@ -40,7 +40,15 @@ import org.elasticsearch.search.aggregations.metrics.max.MaxAggregationBuilder;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static org.elasticsearch.search.aggregations.AggregationBuilders.max;
+import static org.elasticsearch.search.aggregations.AggregationBuilders.nested;
+import static org.elasticsearch.search.aggregations.AggregationBuilders.reverseNested;
 
 public class ReverseNestedAggregatorTests extends AggregatorTestCase {
 
@@ -50,6 +58,15 @@ public class ReverseNestedAggregatorTests extends AggregatorTestCase {
     private static final String REVERSE_AGG_NAME = "reverseNestedAgg";
     private static final String MAX_AGG_NAME = "maxAgg";
 
+    /**
+     * For each provided field type, we also register an alias with name <field>-alias.
+     */
+    @Override
+    protected Map<String, MappedFieldType> getFieldAliases(MappedFieldType... fieldTypes) {
+        return Arrays.stream(fieldTypes).collect(Collectors.toMap(
+            ft -> ft.name() + "-alias",
+            Function.identity()));
+    }
 
     public void testNoDocs() throws IOException {
         try (Directory directory = newDirectory()) {
@@ -150,4 +167,63 @@ public class ReverseNestedAggregatorTests extends AggregatorTestCase {
         }
     }
 
+    public void testFieldAlias() throws IOException {
+        int numParentDocs = randomIntBetween(1, 20);
+
+        MappedFieldType fieldType = new NumberFieldMapper.NumberFieldType(
+            NumberFieldMapper.NumberType.LONG);
+        fieldType.setName(VALUE_FIELD_NAME);
+
+        try (Directory directory = newDirectory()) {
+            try (RandomIndexWriter iw = new RandomIndexWriter(random(), directory)) {
+                for (int i = 0; i < numParentDocs; i++) {
+                    List<Document> documents = new ArrayList<>();
+                    int numNestedDocs = randomIntBetween(0, 20);
+                    for (int nested = 0; nested < numNestedDocs; nested++) {
+                        Document document = new Document();
+                        document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(i)),
+                                IdFieldMapper.Defaults.NESTED_FIELD_TYPE));
+                        document.add(new Field(TypeFieldMapper.NAME, "__" + NESTED_OBJECT,
+                                TypeFieldMapper.Defaults.FIELD_TYPE));
+                        documents.add(document);
+                    }
+                    Document document = new Document();
+                    document.add(new Field(IdFieldMapper.NAME, Uid.encodeId(Integer.toString(i)),
+                            IdFieldMapper.Defaults.FIELD_TYPE));
+                    document.add(new Field(TypeFieldMapper.NAME, "test",
+                            TypeFieldMapper.Defaults.FIELD_TYPE));
+
+                    long value = randomNonNegativeLong() % 10000;
+                    document.add(new SortedNumericDocValuesField(VALUE_FIELD_NAME, value));
+                    document.add(SeqNoFieldMapper.SequenceIDFields.emptySeqID().primaryTerm);
+                    documents.add(document);
+                    iw.addDocuments(documents);
+                }
+                iw.commit();
+            }
+
+            try (IndexReader indexReader = wrap(DirectoryReader.open(directory))) {
+
+                MaxAggregationBuilder maxAgg = max(MAX_AGG_NAME).field(VALUE_FIELD_NAME);
+                MaxAggregationBuilder aliasMaxAgg = max(MAX_AGG_NAME).field(VALUE_FIELD_NAME + "-alias");
+
+                NestedAggregationBuilder agg = nested(NESTED_AGG, NESTED_OBJECT).subAggregation(
+                    reverseNested(REVERSE_AGG_NAME).subAggregation(maxAgg));
+                NestedAggregationBuilder aliasAgg = nested(NESTED_AGG, NESTED_OBJECT).subAggregation(
+                    reverseNested(REVERSE_AGG_NAME).subAggregation(aliasMaxAgg));
+
+                Nested nested = search(newSearcher(indexReader, false, true),
+                        new MatchAllDocsQuery(), agg, fieldType);
+                Nested aliasNested = search(newSearcher(indexReader, false, true),
+                    new MatchAllDocsQuery(), aliasAgg, fieldType);
+
+                ReverseNested reverseNested = nested.getAggregations().get(REVERSE_AGG_NAME);
+                ReverseNested aliasReverseNested = aliasNested.getAggregations().get(REVERSE_AGG_NAME);
+
+                assertTrue(reverseNested.getDocCount() > 0);
+                assertEquals(reverseNested, aliasReverseNested);
+            }
+        }
+    }
+
 }

server/src/test/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantTermsAggregatorTests.java

@@ -55,7 +55,13 @@ import org.hamcrest.Matchers;
 import org.junit.Before;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static org.elasticsearch.search.aggregations.AggregationBuilders.significantTerms;
 
 public class SignificantTermsAggregatorTests extends AggregatorTestCase {
 
@@ -70,6 +76,16 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
         fieldType.setName("field");
     }
 
+    /**
+     * For each provided field type, we also register an alias with name <field>-alias.
+     */
+    @Override
+    protected Map<String, MappedFieldType> getFieldAliases(MappedFieldType... fieldTypes) {
+        return Arrays.stream(fieldTypes).collect(Collectors.toMap(
+            ft -> ft.name() + "-alias",
+            Function.identity()));
+    }
+
     public void testParsedAsFilter() throws IOException {
         IndexReader indexReader = new MultiReader();
         IndexSearcher indexSearcher = newSearcher(indexReader);
@@ -104,7 +120,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
         IndexWriterConfig indexWriterConfig = newIndexWriterConfig();
         indexWriterConfig.setMaxBufferedDocs(100);
         indexWriterConfig.setRAMBufferSizeMB(100); // flush on open to have a single segment
-        
+
         try (Directory dir = newDirectory(); IndexWriter w = new IndexWriter(dir, indexWriterConfig)) {
             addMixedTextDocs(textFieldType, w);
 
@@ -137,7 +153,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
                 assertNull(terms.getBucketByKey("odd"));
                 assertNull(terms.getBucketByKey("common"));
                 assertNotNull(terms.getBucketByKey("even"));
-                
+
                 // Search odd with regex includeexcludes
                 sigAgg.includeExclude(new IncludeExclude("o.d", null));
                 terms = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")), sigAgg, textFieldType);
@@ -149,7 +165,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
                 // Search with string-based includeexcludes
                 String oddStrings[] = new String[] {"odd", "weird"};
                 String evenStrings[] = new String[] {"even", "regular"};
-                
+
                 sigAgg.includeExclude(new IncludeExclude(oddStrings, evenStrings));
                 sigAgg.significanceHeuristic(SignificanceHeuristicTests.getRandomSignificanceheuristic());
                 terms = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")), sigAgg, textFieldType);
@@ -159,7 +175,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
                 assertNull(terms.getBucketByKey("common"));
                 assertNull(terms.getBucketByKey("even"));
                 assertNull(terms.getBucketByKey("regular"));
-                
+
                 sigAgg.includeExclude(new IncludeExclude(evenStrings, oddStrings));
                 terms = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")), sigAgg, textFieldType);
                 assertEquals(0, terms.getBuckets().size());
@@ -168,7 +184,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
                 assertNull(terms.getBucketByKey("common"));
                 assertNull(terms.getBucketByKey("even"));
                 assertNull(terms.getBucketByKey("regular"));
-                
+
             }
         }
     }
@@ -232,7 +248,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
             }
         }
     }
-    
+
     /**
      * Uses the significant terms aggregation on an index with unmapped field
      */
@@ -266,7 +282,57 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
 
             }
         }
-    }  
+    }
+
+    public void testFieldAlias() throws IOException {
+        TextFieldType textFieldType = new TextFieldType();
+        textFieldType.setName("text");
+        textFieldType.setFielddata(true);
+        textFieldType.setIndexAnalyzer(new NamedAnalyzer("my_analyzer", AnalyzerScope.GLOBAL, new StandardAnalyzer()));
+
+        IndexWriterConfig indexWriterConfig = newIndexWriterConfig();
+        indexWriterConfig.setMaxBufferedDocs(100);
+        indexWriterConfig.setRAMBufferSizeMB(100); // flush on open to have a single segment
+
+        try (Directory dir = newDirectory(); IndexWriter w = new IndexWriter(dir, indexWriterConfig)) {
+            addMixedTextDocs(textFieldType, w);
+
+            SignificantTermsAggregationBuilder agg = significantTerms("sig_text").field("text");
+            SignificantTermsAggregationBuilder aliasAgg = significantTerms("sig_text").field("text-alias");
+
+            String executionHint = randomExecutionHint();
+            agg.executionHint(executionHint);
+            aliasAgg.executionHint(executionHint);
+
+            if (randomBoolean()) {
+                // Use a background filter which just happens to be same scope as whole-index.
+                QueryBuilder backgroundFilter = QueryBuilders.termsQuery("text", "common");
+                agg.backgroundFilter(backgroundFilter);
+                aliasAgg.backgroundFilter(backgroundFilter);
+            }
+
+            try (IndexReader reader = DirectoryReader.open(w)) {
+                assertEquals("test expects a single segment", 1, reader.leaves().size());
+                IndexSearcher searcher = new IndexSearcher(reader);
+
+                SignificantTerms evenTerms = searchAndReduce(searcher, new TermQuery(new Term("text", "even")),
+                    agg, textFieldType);
+                SignificantTerms aliasEvenTerms = searchAndReduce(searcher, new TermQuery(new Term("text", "even")),
+                    aliasAgg, textFieldType);
+
+                assertFalse(evenTerms.getBuckets().isEmpty());
+                assertEquals(evenTerms, aliasEvenTerms);
+
+                SignificantTerms oddTerms = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")),
+                    agg, textFieldType);
+                SignificantTerms aliasOddTerms = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")),
+                    aliasAgg, textFieldType);
+
+                assertFalse(oddTerms.getBuckets().isEmpty());
+                assertEquals(oddTerms, aliasOddTerms);
+            }
+        }
+    }
 
     private void addMixedTextDocs(TextFieldType textFieldType, IndexWriter w) throws IOException {
         for (int i = 0; i < 10; i++) {
@@ -284,7 +350,7 @@ public class SignificantTermsAggregatorTests extends AggregatorTestCase {
 
             w.addDocument(doc);
         }
-    }    
+    }
 
     private void addFields(Document doc, List<Field> createFields) {
         for (Field field : createFields) {

server/src/test/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantTextAggregatorTests.java

@@ -34,19 +34,34 @@ import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.index.analysis.AnalyzerScope;
 import org.elasticsearch.index.analysis.NamedAnalyzer;
+import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.TextFieldMapper.TextFieldType;
 import org.elasticsearch.search.aggregations.AggregatorTestCase;
 import org.elasticsearch.search.aggregations.bucket.sampler.Sampler;
 import org.elasticsearch.search.aggregations.bucket.sampler.SamplerAggregationBuilder;
-import org.elasticsearch.search.aggregations.bucket.significant.SignificantTerms;
-import org.elasticsearch.search.aggregations.bucket.significant.SignificantTextAggregationBuilder;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static org.elasticsearch.search.aggregations.AggregationBuilders.sampler;
+import static org.elasticsearch.search.aggregations.AggregationBuilders.significantText;
 
 public class SignificantTextAggregatorTests extends AggregatorTestCase {
-  
-    
+
+    /**
+     * For each provided field type, we also register an alias with name <field>-alias.
+     */
+    @Override
+    protected Map<String, MappedFieldType> getFieldAliases(MappedFieldType... fieldTypes) {
+        return Arrays.stream(fieldTypes).collect(Collectors.toMap(
+            ft -> ft.name() + "-alias",
+            Function.identity()));
+    }
+
     /**
      * Uses the significant text aggregation to find the keywords in text fields
      */
@@ -59,22 +74,7 @@ public class SignificantTextAggregatorTests extends AggregatorTestCase {
         indexWriterConfig.setMaxBufferedDocs(100);
         indexWriterConfig.setRAMBufferSizeMB(100); // flush on open to have a single segment
         try (Directory dir = newDirectory(); IndexWriter w = new IndexWriter(dir, indexWriterConfig)) {
-            for (int i = 0; i < 10; i++) {
-                Document doc = new Document();
-                StringBuilder text = new StringBuilder("common ");
-                if (i % 2 == 0) {
-                    text.append("odd ");
-                } else {                    
-                    text.append("even separator" + i + " duplicate duplicate duplicate duplicate duplicate duplicate ");
-                }
-
-                doc.add(new Field("text", text.toString(), textFieldType));
-                String json ="{ \"text\" : \"" + text.toString() + "\","+
-                             " \"json_only_field\" : \"" + text.toString() + "\"" +
-                            " }";
-                doc.add(new StoredField("_source", new BytesRef(json)));
-                w.addDocument(doc);
-            }
+            indexDocuments(w, textFieldType);
 
             SignificantTextAggregationBuilder sigAgg = new SignificantTextAggregationBuilder("sig_text", "text").filterDuplicateText(true);
             if(randomBoolean()){
@@ -82,37 +82,104 @@ public class SignificantTextAggregatorTests extends AggregatorTestCase {
             }
             SamplerAggregationBuilder aggBuilder = new SamplerAggregationBuilder("sampler")
                     .subAggregation(sigAgg);
-            
+
             try (IndexReader reader = DirectoryReader.open(w)) {
                 assertEquals("test expects a single segment", 1, reader.leaves().size());
                 IndexSearcher searcher = new IndexSearcher(reader);
-                                
+
                 // Search "odd" which should have no duplication
                 Sampler sampler = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")), aggBuilder, textFieldType);
                 SignificantTerms terms = sampler.getAggregations().get("sig_text");
-                
+
                 assertNull(terms.getBucketByKey("even"));
-                assertNull(terms.getBucketByKey("duplicate"));                
-                assertNull(terms.getBucketByKey("common"));                
+                assertNull(terms.getBucketByKey("duplicate"));
+                assertNull(terms.getBucketByKey("common"));
                 assertNotNull(terms.getBucketByKey("odd"));
 
                 // Search "even" which will have duplication
                 sampler = searchAndReduce(searcher, new TermQuery(new Term("text", "even")), aggBuilder, textFieldType);
                 terms = sampler.getAggregations().get("sig_text");
-                
+
                 assertNull(terms.getBucketByKey("odd"));
-                assertNull(terms.getBucketByKey("duplicate"));                
-                assertNull(terms.getBucketByKey("common"));    
+                assertNull(terms.getBucketByKey("duplicate"));
+                assertNull(terms.getBucketByKey("common"));
                 assertNull(terms.getBucketByKey("separator2"));
                 assertNull(terms.getBucketByKey("separator4"));
                 assertNull(terms.getBucketByKey("separator6"));
 
                 assertNotNull(terms.getBucketByKey("even"));
-            
+
             }
         }
     }
-    
+
+    public void testFieldAlias() throws IOException {
+        TextFieldType textFieldType = new TextFieldType();
+        textFieldType.setName("text");
+        textFieldType.setIndexAnalyzer(new NamedAnalyzer("my_analyzer", AnalyzerScope.GLOBAL, new StandardAnalyzer()));
+
+        IndexWriterConfig indexWriterConfig = newIndexWriterConfig();
+        indexWriterConfig.setMaxBufferedDocs(100);
+        indexWriterConfig.setRAMBufferSizeMB(100); // flush on open to have a single segment
+        try (Directory dir = newDirectory(); IndexWriter w = new IndexWriter(dir, indexWriterConfig)) {
+            indexDocuments(w, textFieldType);
+
+            SignificantTextAggregationBuilder agg = significantText("sig_text", "text")
+                .filterDuplicateText(true);
+            SignificantTextAggregationBuilder aliasAgg = significantText("sig_text", "text-alias")
+                .filterDuplicateText(true);
+
+            if (randomBoolean()) {
+                List<String> sourceFieldNames = Arrays.asList(new String [] {"json_only_field"});
+                agg.sourceFieldNames(sourceFieldNames);
+                aliasAgg.sourceFieldNames(sourceFieldNames);
+            }
+
+            try (IndexReader reader = DirectoryReader.open(w)) {
+                assertEquals("test expects a single segment", 1, reader.leaves().size());
+                IndexSearcher searcher = new IndexSearcher(reader);
+
+                SamplerAggregationBuilder samplerAgg = sampler("sampler").subAggregation(agg);
+                SamplerAggregationBuilder aliasSamplerAgg = sampler("sampler").subAggregation(aliasAgg);
+
+                Sampler sampler = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")), samplerAgg, textFieldType);
+                Sampler aliasSampler = searchAndReduce(searcher, new TermQuery(new Term("text", "odd")), aliasSamplerAgg, textFieldType);
+
+                SignificantTerms terms = sampler.getAggregations().get("sig_text");
+                SignificantTerms aliasTerms = aliasSampler.getAggregations().get("sig_text");
+                assertFalse(terms.getBuckets().isEmpty());
+                assertEquals(terms, aliasTerms);
+
+                sampler = searchAndReduce(searcher, new TermQuery(new Term("text", "even")), samplerAgg, textFieldType);
+                aliasSampler = searchAndReduce(searcher, new TermQuery(new Term("text", "even")), aliasSamplerAgg, textFieldType);
+
+                terms = sampler.getAggregations().get("sig_text");
+                aliasTerms = aliasSampler.getAggregations().get("sig_text");
+                assertFalse(terms.getBuckets().isEmpty());
+                assertEquals(terms, aliasTerms);
+            }
+        }
+    }
+
+    private void indexDocuments(IndexWriter writer, TextFieldType textFieldType) throws IOException {
+        for (int i = 0; i < 10; i++) {
+            Document doc = new Document();
+            StringBuilder text = new StringBuilder("common ");
+            if (i % 2 == 0) {
+                text.append("odd ");
+            } else {
+                text.append("even separator" + i + " duplicate duplicate duplicate duplicate duplicate duplicate ");
+            }
+
+            doc.add(new Field("text", text.toString(), textFieldType));
+            String json ="{ \"text\" : \"" + text.toString() + "\","+
+                " \"json_only_field\" : \"" + text.toString() + "\"" +
+                " }";
+            doc.add(new StoredField("_source", new BytesRef(json)));
+            writer.addDocument(doc);
+        }
+    }
+
     /**
      * Test documents with arrays of text
      */
@@ -137,13 +204,13 @@ public class SignificantTextAggregatorTests extends AggregatorTestCase {
             sigAgg.sourceFieldNames(Arrays.asList(new String [] {"title", "text"}));
             try (IndexReader reader = DirectoryReader.open(w)) {
                 assertEquals("test expects a single segment", 1, reader.leaves().size());
-                IndexSearcher searcher = new IndexSearcher(reader);                                
+                IndexSearcher searcher = new IndexSearcher(reader);
                 searchAndReduce(searcher, new TermQuery(new Term("text", "foo")), sigAgg, textFieldType);
                 // No significant results to be found in this test - only checking we don't end up
                 // with the internal exception discovered in issue https://github.com/elastic/elasticsearch/issues/25029
             }
         }
     }
-    
-    
+
+
 }

server/src/test/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregatorTests.java

@@ -809,12 +809,12 @@ public class TermsAggregatorTests extends AggregatorTestCase {
                 fieldType1.setHasDocValues(true);
 
                 MappedFieldType fieldType2 = new NumberFieldMapper.NumberFieldType(NumberFieldMapper.NumberType.LONG);
-                fieldType1.setName("another_long");
-                fieldType1.setHasDocValues(true);
+                fieldType2.setName("another_long");
+                fieldType2.setHasDocValues(true);
 
                 MappedFieldType fieldType3 = new NumberFieldMapper.NumberFieldType(NumberFieldMapper.NumberType.DOUBLE);
-                fieldType1.setName("another_double");
-                fieldType1.setHasDocValues(true);
+                fieldType3.setName("another_double");
+                fieldType3.setHasDocValues(true);
                 try (IndexReader indexReader = maybeWrapReaderEs(indexWriter.getReader())) {
                     IndexSearcher indexSearcher = newIndexSearcher(indexReader);
                     ValueType[] valueTypes = new ValueType[]{ValueType.STRING, ValueType.LONG, ValueType.DOUBLE};

server/src/test/java/org/elasticsearch/search/aggregations/metrics/SumIT.java

@@ -18,12 +18,7 @@
  */
 package org.elasticsearch.search.aggregations.metrics;
 
-import java.util.Collection;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
+import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.plugins.Plugin;
@@ -36,6 +31,14 @@ import org.elasticsearch.search.aggregations.bucket.global.Global;
 import org.elasticsearch.search.aggregations.bucket.histogram.Histogram;
 import org.elasticsearch.search.aggregations.bucket.terms.Terms;
 import org.elasticsearch.search.aggregations.metrics.sum.Sum;
+import org.hamcrest.core.IsNull;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
 import static org.elasticsearch.index.query.QueryBuilders.termQuery;
@@ -61,6 +64,33 @@ public class SumIT extends AbstractNumericTestCase {
         return Collections.singleton(MetricAggScriptPlugin.class);
     }
 
+    @Override
+    public void setupSuiteScopeCluster() throws Exception {
+        super.setupSuiteScopeCluster();
+
+        // Create two indices and add the field 'route_length_miles' as an alias in
+        // one, and a concrete field in the other.
+        prepareCreate("old_index")
+            .addMapping("_doc",
+                "transit_mode", "type=keyword",
+                "distance", "type=double",
+                "route_length_miles", "type=alias,path=distance")
+            .get();
+        prepareCreate("new_index")
+            .addMapping("_doc",
+                "transit_mode", "type=keyword",
+                "route_length_miles", "type=double")
+            .get();
+
+        List<IndexRequestBuilder> builders = new ArrayList<>();
+        builders.add(client().prepareIndex("old_index", "_doc").setSource("transit_mode", "train", "distance", 42.0));
+        builders.add(client().prepareIndex("old_index", "_doc").setSource("transit_mode", "bus", "distance", 50.5));
+        builders.add(client().prepareIndex("new_index", "_doc").setSource("transit_mode", "train", "route_length_miles", 100.2));
+
+        indexRandom(true, builders);
+        ensureSearchable();
+    }
+
     @Override
     public void testEmptyAggregation() throws Exception {
 
@@ -382,4 +412,54 @@ public class SumIT extends AbstractNumericTestCase {
         assertThat(client().admin().indices().prepareStats("cache_test_idx").setRequestCache(true).get().getTotal().getRequestCache()
                 .getMissCount(), equalTo(1L));
     }
+
+    public void testFieldAlias() {
+        SearchResponse response = client().prepareSearch("old_index", "new_index")
+            .addAggregation(sum("sum")
+                .field("route_length_miles"))
+            .execute().actionGet();
+
+        assertSearchResponse(response);
+
+        Sum sum = response.getAggregations().get("sum");
+        assertThat(sum, IsNull.notNullValue());
+        assertThat(sum.getName(), equalTo("sum"));
+        assertThat(sum.getValue(), equalTo(192.7));
+    }
+
+     public void testFieldAliasInSubAggregation() {
+        SearchResponse response = client().prepareSearch("old_index", "new_index")
+            .addAggregation(terms("terms")
+                .field("transit_mode")
+                .subAggregation(sum("sum")
+                    .field("route_length_miles")))
+            .execute().actionGet();
+
+        assertSearchResponse(response);
+
+        Terms terms = response.getAggregations().get("terms");
+        assertThat(terms, notNullValue());
+        assertThat(terms.getName(), equalTo("terms"));
+
+        List<? extends Terms.Bucket> buckets = terms.getBuckets();
+        assertThat(buckets.size(), equalTo(2));
+
+        Terms.Bucket bucket = buckets.get(0);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("train"));
+        assertThat(bucket.getDocCount(), equalTo(2L));
+
+        Sum sum = bucket.getAggregations().get("sum");
+        assertThat(sum, notNullValue());
+        assertThat(sum.getValue(), equalTo(142.2));
+
+        bucket = buckets.get(1);
+        assertThat(bucket, notNullValue());
+        assertThat(bucket.getKey(), equalTo("bus"));
+        assertThat(bucket.getDocCount(), equalTo(1L));
+
+        sum = bucket.getAggregations().get("sum");
+        assertThat(sum, notNullValue());
+        assertThat(sum.getValue(), equalTo(50.5));
+    }
 }