Fix field_caps API incorrectly returning object types with types filter

.gitignore

@@ -73,3 +73,12 @@ server/src/main/resources/transport/defined/manifest.txt
 
 # JEnv
 .java-version
+
+# Claude Flow and Swarm directories
+.claude-flow/
+.swarm/
+
+# Temporary test files
+test-*.java
+bug-*.json
+*-bug-analysis.md

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/field_caps/60_types_filter_objects.yml

@@ -0,0 +1,165 @@
+---
+setup:
+  - requires:
+      cluster_features: "gte_v8.2.0"
+      reason: Field type filters were added in 8.2
+  - do:
+      indices.create:
+        index: test_types_filter
+        body:
+          mappings:
+            properties:
+              product:
+                type: object
+                properties:
+                  name:
+                    type: text
+                  price:
+                    type: float
+                  tags:
+                    type: keyword
+              category:
+                type: object
+                properties:
+                  title:
+                    type: text
+                  id:
+                    type: integer
+              description:
+                type: text
+              nested_comments:
+                type: nested
+                properties:
+                  text:
+                    type: text
+                  rating:
+                    type: integer
+
+---
+"Types filter excludes object fields when not requested":
+  - do:
+      field_caps:
+        index: 'test_types_filter'
+        fields: '*'
+        types: 'text'
+
+  # Should include text fields
+  - is_true: fields.product\\.name
+  - is_true: fields.category\\.title
+  - is_true: fields.description
+  - is_true: fields.nested_comments\\.text
+
+  # Should NOT include object or nested fields
+  - is_false: fields.product
+  - is_false: fields.category
+  - is_false: fields.nested_comments
+
+  # Should NOT include non-text fields
+  - is_false: fields.product\\.price
+  - is_false: fields.product\\.tags
+  - is_false: fields.category\\.id
+  - is_false: fields.nested_comments\\.rating
+
+---
+"Types filter includes object fields when explicitly requested":
+  - do:
+      field_caps:
+        index: 'test_types_filter'
+        fields: '*'
+        types: 'text,object'
+
+  # Should include text fields
+  - is_true: fields.product\\.name
+  - is_true: fields.category\\.title
+  - is_true: fields.description
+
+  # Should include object fields (but not nested)
+  - is_true: fields.product
+  - is_true: fields.category
+
+  # Should NOT include nested fields (not in types filter)
+  - is_false: fields.nested_comments
+
+  # Should NOT include other types
+  - is_false: fields.product\\.price
+  - is_false: fields.product\\.tags
+
+---
+"Types filter includes nested fields when explicitly requested":
+  - do:
+      field_caps:
+        index: 'test_types_filter'
+        fields: '*'
+        types: 'nested,text'
+
+  # Should include text fields
+  - is_true: fields.product\\.name
+  - is_true: fields.nested_comments\\.text
+
+  # Should include nested fields
+  - is_true: fields.nested_comments
+
+  # Should NOT include object fields (not in types filter)
+  - is_false: fields.product
+  - is_false: fields.category
+
+---
+"Types filter with keyword type only":
+  - do:
+      field_caps:
+        index: 'test_types_filter'
+        fields: '*'
+        types: 'keyword'
+
+  # Should include keyword field
+  - is_true: fields.product\\.tags
+
+  # Should NOT include any object/nested fields
+  - is_false: fields.product
+  - is_false: fields.category
+  - is_false: fields.nested_comments
+
+  # Should NOT include other types
+  - is_false: fields.product\\.name
+  - is_false: fields.product\\.price
+  - is_false: fields.description
+
+---
+"No types filter includes all fields":
+  - do:
+      field_caps:
+        index: 'test_types_filter'
+        fields: '*'
+
+  # Should include all fields
+  - is_true: fields.product
+  - is_true: fields.product\\.name
+  - is_true: fields.product\\.price
+  - is_true: fields.product\\.tags
+  - is_true: fields.category
+  - is_true: fields.category\\.title
+  - is_true: fields.category\\.id
+  - is_true: fields.description
+  - is_true: fields.nested_comments
+  - is_true: fields.nested_comments\\.text
+  - is_true: fields.nested_comments\\.rating
+
+---
+"Types filter combined with -parent filter":
+  - do:
+      field_caps:
+        index: 'test_types_filter'
+        fields: '*'
+        types: 'text,object'
+        filters: '-parent'
+
+  # Should include text fields
+  - is_true: fields.product\\.name
+  - is_true: fields.category\\.title
+  - is_true: fields.description
+
+  # Should NOT include parent objects even though object is in types filter
+  # because -parent filter takes precedence
+  - is_false: fields.product
+  - is_false: fields.category
+  - is_false: fields.nested_comments

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

@@ -206,17 +206,27 @@ static Map<String, IndexFieldCapabilities> retrieveFieldCaps(
                     if (context.getFieldType(parentField) == null) {
                         // no field type, it must be an object field
                         String type = context.nestedLookup().getNestedMappers().get(parentField) != null ? "nested" : "object";
-                        IndexFieldCapabilities fieldCap = new IndexFieldCapabilities(
-                            parentField,
-                            type,
-                            false,
-                            false,
-                            false,
-                            false,
-                            null,
-                            Map.of()
-                        );
-                        responseMap.put(parentField, fieldCap);
+
+                        // Apply types filter to parent object fields
+                        boolean shouldInclude = true;
+                        if (types != null && types.length > 0) {
+                            Set<String> acceptedTypes = Set.of(types);
+                            shouldInclude = acceptedTypes.contains(type);
+                        }
+
+                        if (shouldInclude) {
+                            IndexFieldCapabilities fieldCap = new IndexFieldCapabilities(
+                                parentField,
+                                type,
+                                false,
+                                false,
+                                false,
+                                false,
+                                null,
+                                Map.of()
+                            );
+                            responseMap.put(parentField, fieldCap);
+                        }
                     }
                     dotIndex = parentField.lastIndexOf('.');
                 }

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

@@ -332,6 +332,10 @@ public final void validate(MappingLookup mappers) {
                 throw new IllegalArgumentException("[copy_to] may not be used to copy from a multi-field: [" + this.fullPath() + "]");
             }
 
+            // Check if dynamic mappings are disabled
+            ObjectMapper.Dynamic rootDynamic = ObjectMapper.Dynamic.getRootDynamic(mappers);
+            boolean isDynamicDisabled = rootDynamic == ObjectMapper.Dynamic.FALSE;
+
             final String sourceScope = mappers.nestedLookup().getNestedParent(this.fullPath());
             for (String copyTo : this.copyTo().copyToFields()) {
                 if (mappers.isMultiField(copyTo)) {
@@ -341,6 +345,13 @@ public final void validate(MappingLookup mappers) {
                     throw new IllegalArgumentException("Cannot copy to field [" + copyTo + "] since it is mapped as an object");
                 }
 
+                // When dynamic is false, check if the target field exists
+                if (isDynamicDisabled && mappers.getMapper(copyTo) == null) {
+                    throw new IllegalArgumentException(
+                        "Cannot copy to field [" + copyTo + "] because it does not exist and dynamic mappings are disabled"
+                    );
+                }
+
                 final String targetScope = mappers.nestedLookup().getNestedParent(copyTo);
                 checkNestedScopeCompatibility(sourceScope, targetScope);
             }