Automatically upgrade analyzed string fields that have `index_options` or `position_increment_gap` set. #20002

Closes #19974

core/src/main/java/org/elasticsearch/index/mapper/StringFieldMapper.java

@@ -22,13 +22,9 @@ package org.elasticsearch.index.mapper;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.index.IndexOptions;
-import org.apache.lucene.index.Term;
-import org.apache.lucene.search.MultiTermQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.RegexpQuery;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.Version;
-import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.logging.ESLogger;
 import org.elasticsearch.common.logging.Loggers;
@@ -40,7 +36,6 @@ import org.elasticsearch.index.analysis.NamedAnalyzer;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.plain.DocValuesIndexFieldData;
 import org.elasticsearch.index.fielddata.plain.PagedBytesIndexFieldData;
-import org.elasticsearch.index.query.QueryShardContext;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -71,7 +66,8 @@ public class StringFieldMapper extends FieldMapper implements AllFieldMapper.Inc
             "type",
             // common text parameters, for which the upgrade is straightforward
             "index", "store", "doc_values", "omit_norms", "norms", "fields", "copy_to",
-            "fielddata", "include_in_all", "analyzer", "search_analyzer", "search_quote_analyzer"));
+            "fielddata", "include_in_all", "analyzer", "search_analyzer", "search_quote_analyzer",
+            "index_options", "position_increment_gap"));
 
     public static class Defaults {
         public static double FIELDDATA_MIN_FREQUENCY = 0;
@@ -259,7 +255,10 @@ public class StringFieldMapper extends FieldMapper implements AllFieldMapper.Inc
                     }
 
                 }
-                throw new IllegalArgumentException("The [string] type is removed in 5.0. You should now use either a [text] "
+                Set<String> unsupportedParameters = new HashSet<>(node.keySet());
+                unsupportedParameters.removeAll(autoUpgradeParameters);
+                throw new IllegalArgumentException("The [string] type is removed in 5.0 and automatic upgrade failed because parameters "
+                        + unsupportedParameters + " are not supported for automatic upgrades. You should now use either a [text] "
                         + "or [keyword] field instead for field [" + fieldName + "]");
             }
 

core/src/test/java/org/elasticsearch/index/mapper/StringMappingUpgradeTests.java

@@ -106,6 +106,32 @@ public class StringMappingUpgradeTests extends ESSingleNodeTestCase {
         assertEquals(IndexOptions.NONE, field.fieldType().indexOptions());
     }
 
+    public void testUpgradeIndexOptions() throws IOException {
+        IndexService indexService = createIndex("test");
+        DocumentMapperParser parser = indexService.mapperService().documentMapperParser();
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+                .startObject("properties").startObject("field").field("type", "string")
+                .field("index_options", "offsets").endObject().endObject()
+                .endObject().endObject().string();
+        DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
+        FieldMapper field = mapper.mappers().getMapper("field");
+        assertThat(field, instanceOf(TextFieldMapper.class));
+        assertEquals(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS, field.fieldType().indexOptions());
+    }
+
+    public void testUpgradePositionGap() throws IOException {
+        IndexService indexService = createIndex("test");
+        DocumentMapperParser parser = indexService.mapperService().documentMapperParser();
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+                .startObject("properties").startObject("field").field("type", "string")
+                .field("position_increment_gap", 42).endObject().endObject()
+                .endObject().endObject().string();
+        DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
+        FieldMapper field = mapper.mappers().getMapper("field");
+        assertThat(field, instanceOf(TextFieldMapper.class));
+        assertEquals(42, field.fieldType().indexAnalyzer().getPositionIncrementGap("field"));
+    }
+
     public void testIllegalIndexValue() throws IOException {
         IndexService indexService = createIndex("test");
         DocumentMapperParser parser = indexService.mapperService().documentMapperParser();
@@ -297,7 +323,11 @@ public class StringMappingUpgradeTests extends ESSingleNodeTestCase {
         }
         if (randomBoolean()) {
             // this option is not upgraded automatically
-            mapping.field("index_options", "docs");
+            if (keyword) {
+                mapping.field("index_options", "docs");
+            } else {
+                mapping.field("ignore_above", 30);
+            }
             shouldUpgrade = false;
         }
         mapping.endObject().endObject().endObject().endObject();