Allow big integers and decimals to be mapped dynamically. (#42827)

This PR proposes to model big integers as longs (and big decimals as doubles)
in the context of dynamic mappings.

Previously, the dynamic mapping logic did not recognize big integers or
decimals, and would an error of the form "No matching token for number_type
[BIG_INTEGER]" when a dynamic big integer was encountered. It now accepts these
numeric types and interprets them as 'long' and 'double' respectively. This
allows `dynamic_templates` to accept and and remap them as another type such as
`keyword` or `scaled_float`.

Addresses #37846.

libs/x-content/src/main/java/org/elasticsearch/common/xcontent/XContentParser.java

@@ -114,7 +114,7 @@ public interface XContentParser extends Closeable {
     }
 
     enum NumberType {
-        INT, LONG, FLOAT, DOUBLE
+        INT, BIG_INTEGER, LONG, FLOAT, DOUBLE, BIG_DECIMAL
     }
 
     XContentType contentType();

libs/x-content/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentParser.java

@@ -199,12 +199,16 @@ public class JsonXContentParser extends AbstractXContentParser {
         switch (numberType) {
             case INT:
                 return NumberType.INT;
+            case BIG_INTEGER:
+                return NumberType.BIG_INTEGER;
             case LONG:
                 return NumberType.LONG;
             case FLOAT:
                 return NumberType.FLOAT;
             case DOUBLE:
                 return NumberType.DOUBLE;
+            case BIG_DECIMAL:
+                return NumberType.BIG_DECIMAL;
         }
         throw new IllegalStateException("No matching token for number_type [" + numberType + "]");
     }

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

@@ -765,13 +765,17 @@ final class DocumentParser {
             return builder;
         } else if (token == XContentParser.Token.VALUE_NUMBER) {
             XContentParser.NumberType numberType = context.parser().numberType();
-            if (numberType == XContentParser.NumberType.INT || numberType == XContentParser.NumberType.LONG) {
+            if (numberType == XContentParser.NumberType.INT
+                    || numberType == XContentParser.NumberType.LONG
+                    || numberType == XContentParser.NumberType.BIG_INTEGER) {
                 Mapper.Builder builder = context.root().findTemplateBuilder(context, currentFieldName, XContentFieldType.LONG);
                 if (builder == null) {
                     builder = newLongBuilder(currentFieldName, context.indexSettings().getIndexVersionCreated());
                 }
                 return builder;
-            } else if (numberType == XContentParser.NumberType.FLOAT || numberType == XContentParser.NumberType.DOUBLE) {
+            } else if (numberType == XContentParser.NumberType.FLOAT
+                    || numberType == XContentParser.NumberType.DOUBLE
+                    || numberType == XContentParser.NumberType.BIG_DECIMAL) {
                 Mapper.Builder builder = context.root().findTemplateBuilder(context, currentFieldName, XContentFieldType.DOUBLE);
                 if (builder == null) {
                     // no templates are defined, we use float by default instead of double

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

@@ -19,6 +19,8 @@
 
 package org.elasticsearch.index.mapper;
 
+import org.apache.lucene.index.IndexableField;
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.Strings;
@@ -37,6 +39,8 @@ import org.elasticsearch.test.ESSingleNodeTestCase;
 import org.elasticsearch.test.InternalSettingsPlugin;
 
 import java.io.IOException;
+import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -706,6 +710,62 @@ public class DocumentParserTests extends ESSingleNodeTestCase {
         assertEquals(0, doc.rootDoc().getFields("foo").length);
     }
 
+    public void testDynamicBigInteger() throws Exception {
+        DocumentMapperParser mapperParser = createIndex("test").mapperService().documentMapperParser();
+        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+            .startObject("type")
+                .startArray("dynamic_templates").startObject()
+                    .startObject("big-integer-to-keyword")
+                        .field("match", "big-*")
+                        .field("match_mapping_type", "long")
+                        .startObject("mapping").field("type", "keyword").endObject()
+                    .endObject()
+                .endObject().endArray()
+            .endObject()
+        .endObject());
+
+        DocumentMapper mapper = mapperParser.parse("type", new CompressedXContent(mapping));
+        BigInteger value = BigInteger.valueOf(Long.MAX_VALUE).add(BigInteger.ONE);
+        BytesReference bytes = BytesReference.bytes(XContentFactory.jsonBuilder().startObject()
+            .field("big-integer", value)
+        .endObject());
+        ParsedDocument doc = mapper.parse(new SourceToParse("test", "type", "1", bytes, XContentType.JSON));
+
+        IndexableField[] fields = doc.rootDoc().getFields("big-integer");
+        assertEquals(2, fields.length);
+        assertTrue(fields[0].fieldType() instanceof KeywordFieldMapper.KeywordFieldType);
+        assertEquals(new BytesRef(value.toString()), fields[0].binaryValue());
+    }
+
+    public void testDynamicBigDecimal() throws Exception {
+        DocumentMapperParser mapperParser = createIndex("test").mapperService().documentMapperParser();
+        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+            .startObject("type")
+                .startArray("dynamic_templates").startObject()
+                    .startObject("big-decimal-to-scaled-float")
+                        .field("match", "big-*")
+                        .field("match_mapping_type", "double")
+                        .startObject("mapping")
+                            .field("type", "keyword")
+                        .endObject()
+                    .endObject()
+                .endObject().endArray()
+            .endObject()
+        .endObject());
+
+        BigDecimal value = BigDecimal.valueOf(Double.MAX_VALUE).add(BigDecimal.valueOf(10.1));
+        DocumentMapper mapper = mapperParser.parse("type", new CompressedXContent(mapping));
+        BytesReference bytes = BytesReference.bytes(XContentFactory.jsonBuilder().startObject()
+            .field("big-decimal", value)
+        .endObject());
+        ParsedDocument doc = mapper.parse(new SourceToParse("test", "type", "1", bytes, XContentType.JSON));
+
+        IndexableField[] fields = doc.rootDoc().getFields("big-decimal");
+        assertEquals(2, fields.length);
+        assertTrue(fields[0].fieldType() instanceof KeywordFieldMapper.KeywordFieldType);
+        assertEquals(new BytesRef(value.toString()), fields[0].binaryValue());
+    }
+
     public void testDynamicDottedFieldNameLongArray() throws Exception {
         DocumentMapperParser mapperParser = createIndex("test").mapperService().documentMapperParser();
         String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject().startObject("type")