[8.10] Rollback of #98586 (#98805)

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

@@ -10,7 +10,6 @@
 
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.index.IndexSettings;
-import org.elasticsearch.index.IndexVersion;
 
 import java.util.List;
 
@@ -31,27 +30,16 @@ public static DocumentMapper createEmpty(MapperService mapperService) {
         );
         MetadataFieldMapper[] metadata = mapperService.getMetadataMappers().values().toArray(new MetadataFieldMapper[0]);
         Mapping mapping = new Mapping(root, metadata, null);
-        return new DocumentMapper(mapperService.documentParser(), mapping, mapping.toCompressedXContent(), IndexVersion.current());
+        return new DocumentMapper(mapperService.documentParser(), mapping, mapping.toCompressedXContent());
     }
 
-    DocumentMapper(DocumentParser documentParser, Mapping mapping, CompressedXContent source, IndexVersion version) {
+    DocumentMapper(DocumentParser documentParser, Mapping mapping, CompressedXContent source) {
         this.documentParser = documentParser;
         this.type = mapping.getRoot().name();
         this.mappingLookup = MappingLookup.fromMapping(mapping);
-        if (sourceMapper().isSynthetic()
-            && source.string().contains("\"_source\":{\"mode\":\"synthetic\"}") == false
-            && version.onOrBefore(IndexVersion.V_8_10_0)) {
-            /*
-             * Indexes built at v.8.7 were missing an explicit entry for synthetic_source.
-             * This got restored in v.8.9 (and patched in v.8.8) to avoid confusion. The change is only restricted to
-             * mapping printout, it has no functional effect as the synthetic source already applies.
-             */
-            this.mappingSource = mapping.toCompressedXContent();
-        } else {
-            assert mapping.toCompressedXContent().equals(source)
-                : "provided source [" + source + "] differs from mapping [" + mapping.toCompressedXContent() + "]";
-            this.mappingSource = source;
-        }
+        this.mappingSource = source;
+        assert mapping.toCompressedXContent().equals(source)
+            : "provided source [" + source + "] differs from mapping [" + mapping.toCompressedXContent() + "]";
     }
 
     public Mapping mapping() {

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

@@ -386,7 +386,7 @@ public DocumentMapper merge(String type, CompressedXContent mappingSource, Merge
     }
 
     private DocumentMapper newDocumentMapper(Mapping mapping, MergeReason reason, CompressedXContent mappingSource) {
-        DocumentMapper newMapper = new DocumentMapper(documentParser, mapping, mappingSource, indexVersionCreated);
+        DocumentMapper newMapper = new DocumentMapper(documentParser, mapping, mappingSource);
         newMapper.validate(indexSettings, reason != MergeReason.MAPPING_RECOVERY);
         return newMapper;
     }

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

@@ -86,15 +86,10 @@ public static class Builder extends MetadataFieldMapper.Builder {
             .setMergeValidator(
                 (previous, current, conflicts) -> (previous.value() == current.value()) || (previous.value() && current.value() == false)
             );
-
-        /*
-         * The default mode for TimeSeries is left empty on purpose, so that mapping printings include the synthetic
-         * source mode.
-         */
         private final Parameter<Mode> mode = new Parameter<>(
             "mode",
             true,
-            () -> null,
+            () -> getIndexMode() == IndexMode.TIME_SERIES ? Mode.SYNTHETIC : null,
             (n, c, o) -> Mode.valueOf(o.toString().toUpperCase(Locale.ROOT)),
             m -> toType(m).enabled.explicit() ? null : toType(m).mode,
             (b, n, v) -> b.field(n, v.toString().toLowerCase(Locale.ROOT)),
@@ -141,11 +136,10 @@ private boolean isDefault() {
 
         @Override
         public SourceFieldMapper build() {
-            if (enabled.getValue().explicit()) {
+            if (enabled.getValue().explicit() && mode.get() != null) {
                 if (indexMode == IndexMode.TIME_SERIES) {
                     throw new MapperParsingException("Time series indices only support synthetic source");
-                }
-                if (mode.get() != null) {
+                } else {
                     throw new MapperParsingException("Cannot set both [mode] and [enabled] parameters");
                 }
             }
@@ -223,7 +217,7 @@ private SourceFieldMapper(Mode mode, Explicit<Boolean> enabled, String[] include
         this.sourceFilter = buildSourceFilter(includes, excludes);
         this.includes = includes;
         this.excludes = excludes;
-        if (this.sourceFilter != null && (mode == Mode.SYNTHETIC || indexMode == IndexMode.TIME_SERIES)) {
+        if (this.sourceFilter != null && mode == Mode.SYNTHETIC) {
             throw new IllegalArgumentException("filtering the stored _source is incompatible with synthetic source");
         }
         this.complete = stored() && sourceFilter == null;

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

@@ -69,7 +69,7 @@ public void testAddFields() throws Exception {
         assertThat(stage1.mappers().getMapper("obj1.prop1"), nullValue());
         // but merged should
         DocumentParser documentParser = new DocumentParser(null, null, () -> DocumentParsingObserver.EMPTY_INSTANCE);
-        DocumentMapper mergedMapper = new DocumentMapper(documentParser, merged, merged.toCompressedXContent(), IndexVersion.current());
+        DocumentMapper mergedMapper = new DocumentMapper(documentParser, merged, merged.toCompressedXContent());
         assertThat(mergedMapper.mappers().getMapper("age"), notNullValue());
         assertThat(mergedMapper.mappers().getMapper("obj1.prop1"), notNullValue());
     }

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

@@ -20,7 +20,6 @@
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.IndexSettings;
-import org.elasticsearch.index.IndexVersion;
 import org.elasticsearch.plugins.MapperPlugin;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.script.CompositeFieldScript;
@@ -2531,12 +2530,7 @@ same name need to be part  of the same mappings (hence the same document). If th
 
         // merge without going through toXContent and reparsing, otherwise the potential leaf path issue gets fixed on its own
         Mapping newMapping = MapperService.mergeMappings(mapperService.documentMapper(), mapping, MapperService.MergeReason.MAPPING_UPDATE);
-        DocumentMapper newDocMapper = new DocumentMapper(
-            mapperService.documentParser(),
-            newMapping,
-            newMapping.toCompressedXContent(),
-            IndexVersion.current()
-        );
+        DocumentMapper newDocMapper = new DocumentMapper(mapperService.documentParser(), newMapping, newMapping.toCompressedXContent());
         ParsedDocument doc2 = newDocMapper.parse(source("""
             {
               "foo" : {

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

@@ -12,7 +12,6 @@
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.xcontent.XContentHelper;
-import org.elasticsearch.xcontent.XContentBuilder;
 import org.elasticsearch.xcontent.XContentFactory;
 import org.elasticsearch.xcontent.XContentParser;
 import org.elasticsearch.xcontent.XContentType;
@@ -228,14 +227,4 @@ public void testSyntheticUpdates() throws Exception {
         assertFalse(mapper.enabled());
         assertFalse(mapper.isSynthetic());
     }
-
-    public void testSyntheticSourceInTimeSeries() throws IOException {
-        XContentBuilder mapping = fieldMapping(b -> {
-            b.field("type", "keyword");
-            b.field("time_series_dimension", true);
-        });
-        DocumentMapper mapper = createTimeSeriesModeDocumentMapper(mapping);
-        assertTrue(mapper.sourceMapper().isSynthetic());
-        assertEquals("{\"_source\":{\"mode\":\"synthetic\"}}", mapper.sourceMapper().toString());
-    }
 }