Use flattened names in ignored source (#115822)

* Use flattened names in ignored source

* spotless

* fix rest compat

* fix unittests

* expand dots

rest-api-spec/build.gradle

@@ -59,6 +59,10 @@ tasks.named("yamlRestCompatTestTransform").configure ({ task ->
   task.replaceValueInMatch("profile.shards.0.dfs.knn.0.query.0.description", "DocAndScoreQuery[0,...][0.009673266,...],0.009673266", "dfs knn vector profiling with vector_operations_count")
   task.skipTest("indices.sort/10_basic/Index Sort", "warning does not exist for compatibility")
   task.skipTest("search/330_fetch_fields/Test search rewrite", "warning does not exist for compatibility")
+  task.skipTest("indices.create/20_synthetic_source/object with dynamic override", "temporary until backported")
+  task.skipTest("indices.create/20_synthetic_source/object with unmapped fields", "temporary until backported")
+  task.skipTest("indices.create/20_synthetic_source/empty object with unmapped fields", "temporary until backported")
+  task.skipTest("indices.create/20_synthetic_source/nested object with unmapped fields", "temporary until backported")
   task.skipTest("indices.create/21_synthetic_source_stored/object param - nested object with stored array", "temporary until backported")
   task.skipTest("cat.aliases/10_basic/Deprecated local parameter", "CAT APIs not covered by compatibility policy")
 })

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/indices.create/20_synthetic_source.yml

@@ -1,6 +1,6 @@
 object with unmapped fields:
   - requires:
-      cluster_features: ["mapper.track_ignored_source"]
+      cluster_features: ["mapper.track_ignored_source", "mapper.bwc_workaround_9_0"]
       reason: requires tracking ignored source
 
   - do:
@@ -41,13 +41,13 @@ object with unmapped fields:
   - match: { hits.hits.0._source.some_string: AaAa }
   - match: { hits.hits.0._source.some_int: 1000 }
   - match: { hits.hits.0._source.some_double: 123.456789 }
-  - match: { hits.hits.0._source.a.very.deeply.nested.field: AAAA }
+  - match: { hits.hits.0._source.a: { very.deeply.nested.field: AAAA } }
   - match: { hits.hits.0._source.some_bool: true }
   - match: { hits.hits.1._source.name: bbbb }
   - match: { hits.hits.1._source.some_string: BbBb }
   - match: { hits.hits.1._source.some_int: 2000 }
   - match: { hits.hits.1._source.some_double: 321.987654 }
-  - match: { hits.hits.1._source.a.very.deeply.nested.field: BBBB }
+  - match: { hits.hits.1._source.a: { very.deeply.nested.field: BBBB } }
 
 
 ---
@@ -100,7 +100,7 @@ unmapped arrays:
 ---
 nested object with unmapped fields:
   - requires:
-      cluster_features: ["mapper.track_ignored_source"]
+      cluster_features: ["mapper.track_ignored_source", "mapper.bwc_workaround_9_0"]
       reason: requires tracking ignored source
 
   - do:
@@ -143,16 +143,16 @@ nested object with unmapped fields:
   - match: { hits.total.value: 2 }
   - match: { hits.hits.0._source.path.to.name: aaaa }
   - match: { hits.hits.0._source.path.to.surname: AaAa }
-  - match: { hits.hits.0._source.path.some.other.name: AaAaAa }
+  - match: { hits.hits.0._source.path.some.other\.name: AaAaAa }
   - match: { hits.hits.1._source.path.to.name: bbbb }
   - match: { hits.hits.1._source.path.to.surname: BbBb }
-  - match: { hits.hits.1._source.path.some.other.name: BbBbBb }
+  - match: { hits.hits.1._source.path.some.other\.name: BbBbBb }
 
 
 ---
 empty object with unmapped fields:
   - requires:
-      cluster_features: ["mapper.track_ignored_source"]
+      cluster_features: ["mapper.track_ignored_source", "mapper.bwc_workaround_9_0"]
       reason: requires tracking ignored source
 
   - do:
@@ -191,7 +191,7 @@ empty object with unmapped fields:
 
   - match: { hits.total.value: 1 }
   - match: { hits.hits.0._source.path.to.surname: AaAa }
-  - match: { hits.hits.0._source.path.some.other.name: AaAaAa }
+  - match: { hits.hits.0._source.path.some.other\.name: AaAaAa }
 
 
 ---
@@ -434,7 +434,7 @@ mixed disabled and enabled objects:
 ---
 object with dynamic override:
   - requires:
-      cluster_features: ["mapper.ignored_source.dont_expand_dots"]
+      cluster_features: ["mapper.ignored_source.dont_expand_dots", "mapper.bwc_workaround_9_0"]
       reason: requires tracking ignored source
 
   - do:
@@ -475,7 +475,7 @@ object with dynamic override:
   - match: { hits.hits.0._source.path_no.to: { a.very.deeply.nested.field: A } }
   - match: { hits.hits.0._source.path_runtime.name: bar }
   - match: { hits.hits.0._source.path_runtime.some_int: 20 }
-  - match: { hits.hits.0._source.path_runtime.to.a.very.deeply.nested.field: B }
+  - match: { hits.hits.0._source.path_runtime.to: { a.very.deeply.nested.field: B } }
 
 
 ---

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/indices.create/21_synthetic_source_stored.yml

@@ -1249,3 +1249,52 @@ index param - nested object with stored array:
   - match: { hits.hits.1._source.nested.0.b.1.c: 300 }
   - match: { hits.hits.1._source.nested.1.b.0.c: 40 }
   - match: { hits.hits.1._source.nested.1.b.1.c: 400 }
+
+
+---
+index param - flattened fields:
+  - requires:
+      cluster_features: ["mapper.synthetic_source_keep", "mapper.bwc_workaround_9_0"]
+      reason: requires keeping array source
+
+  - do:
+      indices.create:
+        index: test
+        body:
+          settings:
+            index:
+              mapping:
+                synthetic_source_keep: arrays
+          mappings:
+            _source:
+              mode: synthetic
+            properties:
+              name:
+                type: keyword
+              outer:
+                properties:
+                  inner:
+                    type: object
+
+  - do:
+      bulk:
+        index: test
+        refresh: true
+        body:
+          - '{ "create": { } }'
+          - '{ "name": "A", "outer": { "inner": [ { "a.b": "AA", "a.c": "AAA" } ] } }'
+          - '{ "create": { } }'
+          - '{ "name": "B", "outer": { "inner": [ { "a.x.y.z": "BB", "a.z.y.x": "BBB" } ] } }'
+
+
+  - match: { errors: false }
+
+  - do:
+      search:
+        index: test
+        sort: name
+  - match: { hits.total.value: 2 }
+  - match: { hits.hits.0._source.name: A }
+  - match: { hits.hits.0._source.outer.inner: [{ a.b: AA, a.c: AAA }] }
+  - match: { hits.hits.1._source.name: B }
+  - match: { hits.hits.1._source.outer.inner: [{ a.x.y.z: BB, a.z.y.x: BBB }] }

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

@@ -528,11 +528,7 @@ public abstract class DocumentParserContext {
                     if (canAddIgnoredField()) {
                         try {
                             addIgnoredField(
-                                IgnoredSourceFieldMapper.NameValue.fromContext(
-                                    this,
-                                    mapper.fullPath(),
-                                    XContentDataHelper.encodeToken(parser())
-                                )
+                                IgnoredSourceFieldMapper.NameValue.fromContext(this, mapper.fullPath(), encodeFlattenedToken())
                             );
                         } catch (IOException e) {
                             throw new IllegalArgumentException("failed to parse field [" + mapper.fullPath() + " ]", e);

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

@@ -34,6 +34,10 @@ import java.util.function.Supplier;
  */
 class DotExpandingXContentParser extends FilterXContentParserWrapper {
 
+    static boolean isInstance(XContentParser parser) {
+        return parser instanceof WrappingParser;
+    }
+
     private static final class WrappingParser extends FilterXContentParser {
 
         private final ContentPath contentPath;

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

@@ -221,8 +221,11 @@ public final class XContentDataHelper {
     private static Tuple<XContentParserConfiguration, XContentBuilder> cloneSubContextParserConfiguration(DocumentParserContext context)
         throws IOException {
         XContentParser parser = context.parser();
+        var oldValue = context.path().isWithinLeafObject();
+        context.path().setWithinLeafObject(true);
         XContentBuilder builder = XContentBuilder.builder(parser.contentType().xContent());
         builder.copyCurrentStructure(parser);
+        context.path().setWithinLeafObject(oldValue);
 
         XContentParserConfiguration configuration = XContentParserConfiguration.EMPTY.withRegistry(parser.getXContentRegistry())
             .withDeprecationHandler(parser.getDeprecationHandler())
@@ -235,9 +238,17 @@ public final class XContentDataHelper {
         XContentParserConfiguration configuration,
         XContentBuilder builder
     ) throws IOException {
-        DocumentParserContext subcontext = context.switchParser(
-            XContentHelper.createParserNotCompressed(configuration, BytesReference.bytes(builder), context.parser().contentType())
+        XContentParser newParser = XContentHelper.createParserNotCompressed(
+            configuration,
+            BytesReference.bytes(builder),
+            context.parser().contentType()
         );
+        if (DotExpandingXContentParser.isInstance(context.parser())) {
+            // If we performed dot expanding originally we need to continue to do so when we replace the parser.
+            newParser = DotExpandingXContentParser.expandDots(newParser, context.path());
+        }
+
+        DocumentParserContext subcontext = context.switchParser(newParser);
         subcontext.setRecordedSource();  // Avoids double-storing parts of the source for the same parser subtree.
         subcontext.parser().nextToken();
         return subcontext;

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

@@ -2075,6 +2075,136 @@ public class IgnoredSourceFieldMapperTests extends MapperServiceTestCase {
             {"top":[{"file.name":"A","file.line":10},{"file.name":"B","file.line":20}]}""", syntheticSourceWithArray);
     }
 
+    public void testRegularObjectWithFlatFields() throws IOException {
+        DocumentMapper documentMapper = createMapperService(syntheticSourceMapping(b -> {
+            b.startObject("top").field("type", "object").field("synthetic_source_keep", "all").endObject();
+        })).documentMapper();
+
+        CheckedConsumer<XContentBuilder, IOException> document = b -> {
+            b.startObject("top");
+            b.field("file.name", "A");
+            b.field("file.line", 10);
+            b.endObject();
+        };
+
+        var syntheticSource = syntheticSource(documentMapper, document);
+        assertEquals("{\"top\":{\"file.name\":\"A\",\"file.line\":10}}", syntheticSource);
+
+        CheckedConsumer<XContentBuilder, IOException> documentWithArray = b -> {
+            b.startArray("top");
+            b.startObject();
+            b.field("file.name", "A");
+            b.field("file.line", 10);
+            b.endObject();
+            b.startObject();
+            b.field("file.name", "B");
+            b.field("file.line", 20);
+            b.endObject();
+            b.endArray();
+        };
+
+        var syntheticSourceWithArray = syntheticSource(documentMapper, documentWithArray);
+        assertEquals("""
+            {"top":[{"file.name":"A","file.line":10},{"file.name":"B","file.line":20}]}""", syntheticSourceWithArray);
+    }
+
+    public void testRegularObjectWithFlatFieldsInsideAnArray() throws IOException {
+        DocumentMapper documentMapper = createMapperService(syntheticSourceMapping(b -> {
+            b.startObject("top");
+            b.startObject("properties");
+            {
+                b.startObject("inner").field("type", "object").field("synthetic_source_keep", "all").endObject();
+            }
+            b.endObject();
+            b.endObject();
+        })).documentMapper();
+
+        CheckedConsumer<XContentBuilder, IOException> document = b -> {
+            b.startArray("top");
+            b.startObject();
+            {
+                b.startObject("inner");
+                b.field("file.name", "A");
+                b.field("file.line", 10);
+                b.endObject();
+            }
+            b.endObject();
+            b.endArray();
+        };
+
+        var syntheticSource = syntheticSource(documentMapper, document);
+        assertEquals("{\"top\":{\"inner\":{\"file.name\":\"A\",\"file.line\":10}}}", syntheticSource);
+
+        CheckedConsumer<XContentBuilder, IOException> documentWithArray = b -> {
+            b.startArray("top");
+            b.startObject();
+            {
+                b.startObject("inner");
+                b.field("file.name", "A");
+                b.field("file.line", 10);
+                b.endObject();
+            }
+            b.endObject();
+            b.startObject();
+            {
+                b.startObject("inner");
+                b.field("file.name", "B");
+                b.field("file.line", 20);
+                b.endObject();
+            }
+            b.endObject();
+            b.endArray();
+        };
+
+        var syntheticSourceWithArray = syntheticSource(documentMapper, documentWithArray);
+        assertEquals("""
+            {"top":{"inner":[{"file.name":"A","file.line":10},{"file.name":"B","file.line":20}]}}""", syntheticSourceWithArray);
+    }
+
+    public void testIgnoredDynamicObjectWithFlatFields() throws IOException {
+        var syntheticSource = getSyntheticSourceWithFieldLimit(b -> {
+            b.startObject("top");
+            b.field("file.name", "A");
+            b.field("file.line", 10);
+            b.endObject();
+        });
+        assertEquals("{\"top\":{\"file.name\":\"A\",\"file.line\":10}}", syntheticSource);
+
+        var syntheticSourceWithArray = getSyntheticSourceWithFieldLimit(b -> {
+            b.startArray("top");
+            b.startObject();
+            b.field("file.name", "A");
+            b.field("file.line", 10);
+            b.endObject();
+            b.startObject();
+            b.field("file.name", "B");
+            b.field("file.line", 20);
+            b.endObject();
+            b.endArray();
+        });
+        assertEquals("""
+            {"top":[{"file.name":"A","file.line":10},{"file.name":"B","file.line":20}]}""", syntheticSourceWithArray);
+    }
+
+    public void testStoredArrayWithFlatFields() throws IOException {
+        DocumentMapper documentMapper = createMapperServiceWithStoredArraySource(syntheticSourceMapping(b -> {
+            b.startObject("outer").startObject("properties");
+            {
+                b.startObject("inner").field("type", "object").endObject();
+            }
+            b.endObject().endObject();
+        })).documentMapper();
+        var syntheticSource = syntheticSource(documentMapper, b -> {
+            b.startObject("outer").startArray("inner");
+            {
+                b.startObject().field("a.b", "a.b").field("a.c", "a.c").endObject();
+            }
+            b.endArray().endObject();
+        });
+        assertEquals("""
+            {"outer":{"inner":[{"a.b":"a.b","a.c":"a.c"}]}}""", syntheticSource);
+    }
+
     protected void validateRoundTripReader(String syntheticSource, DirectoryReader reader, DirectoryReader roundTripReader)
         throws IOException {
         // We exclude ignored source field since in some cases it contains an exact copy of a part of document source.