POC - Hide inference results for semantic_text

modules/reindex/src/main/java/org/elasticsearch/reindex/AbstractAsyncBulkByScrollAction.java

@@ -204,6 +204,7 @@ static <Request extends AbstractBulkByScrollRequest<Request>> SearchRequest prep
         }
         sourceBuilder.version(needsSourceDocumentVersions);
         sourceBuilder.seqNoAndPrimaryTerm(needsSourceDocumentSeqNoAndPrimaryTerm);
+        sourceBuilder.hideSourceFields(false);
 
         /*
          * Do not open scroll if max docs <= scroll size and not resuming on version conflicts

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -170,6 +170,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ESQL_REMOVE_ES_SOURCE_OPTIONS = def(8_661_00_0);
     public static final TransportVersion NODE_STATS_INGEST_BYTES = def(8_662_00_0);
     public static final TransportVersion SEMANTIC_QUERY = def(8_663_00_0);
+    public static final TransportVersion HIDE_SOURCE_FIELDS = def(8_664_00_0);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/action/get/TransportGetAction.java

@@ -43,6 +43,7 @@
 import org.elasticsearch.indices.ExecutorSelector;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.node.NodeClosedException;
+import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
@@ -154,7 +155,7 @@ protected GetResponse shardOperation(GetRequest request, ShardId shardId) throws
                 request.realtime(),
                 request.version(),
                 request.versionType(),
-                request.fetchSourceContext(),
+                FetchSourceContext.of(request.fetchSourceContext(), indexShard),
                 request.isForceSyntheticSource()
             );
         return new GetResponse(result);

server/src/main/java/org/elasticsearch/index/reindex/AbstractBulkByScrollRequest.java

@@ -128,6 +128,7 @@ public AbstractBulkByScrollRequest(SearchRequest searchRequest, boolean setDefau
             searchRequest.source(new SearchSourceBuilder());
             searchRequest.source().size(DEFAULT_SCROLL_SIZE);
         }
+        this.searchRequest.source().hideSourceFields(false);
     }
 
     /**

server/src/main/java/org/elasticsearch/search/SearchService.java

@@ -96,6 +96,7 @@
 import org.elasticsearch.search.fetch.ShardFetchRequest;
 import org.elasticsearch.search.fetch.subphase.FetchDocValuesContext;
 import org.elasticsearch.search.fetch.subphase.FetchFieldsContext;
+import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.search.fetch.subphase.ScriptFieldsContext.ScriptField;
 import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
 import org.elasticsearch.search.internal.AliasFilter;
@@ -1345,6 +1346,10 @@ private void parseSource(DefaultSearchContext context, SearchSourceBuilder sourc
         if (source.fetchSource() != null) {
             context.fetchSourceContext(source.fetchSource());
         }
+        if (source.hideSourceFields()) {
+            context.fetchSourceContext(FetchSourceContext.of(source.fetchSource(), context.indexShard()));
+        }
+
         if (source.docValueFields() != null) {
             FetchDocValuesContext docValuesContext = new FetchDocValuesContext(
                 context.getSearchExecutionContext(),

server/src/main/java/org/elasticsearch/search/builder/SearchSourceBuilder.java

@@ -203,6 +203,8 @@ public static HighlightBuilder highlight() {
 
     private Map<String, Object> runtimeMappings = emptyMap();
 
+    private boolean hideSourceFields = true;
+
     /**
      * Constructs a new search source builder.
      */
@@ -279,6 +281,9 @@ public SearchSourceBuilder(StreamInput in) throws IOException {
         if (in.getTransportVersion().onOrAfter(TransportVersions.V_8_8_0)) {
             rankBuilder = in.readOptionalNamedWriteable(RankBuilder.class);
         }
+        if (in.getTransportVersion().onOrAfter(TransportVersions.HIDE_SOURCE_FIELDS)) {
+            hideSourceFields = in.readBoolean();
+        }
     }
 
     @Override
@@ -365,6 +370,9 @@ public void writeTo(StreamOutput out) throws IOException {
         } else if (rankBuilder != null) {
             throw new IllegalArgumentException("cannot serialize [rank] to version [" + out.getTransportVersion().toReleaseVersion() + "]");
         }
+        if (out.getTransportVersion().onOrAfter(TransportVersions.HIDE_SOURCE_FIELDS)) {
+            out.writeBoolean(hideSourceFields);
+        }
     }
 
     /**
@@ -1113,6 +1121,15 @@ public SearchSourceBuilder runtimeMappings(Map<String, Object> runtimeMappings)
         return this;
     }
 
+    public boolean hideSourceFields() {
+        return hideSourceFields;
+    }
+
+    public SearchSourceBuilder hideSourceFields(boolean hideSourceFields) {
+        this.hideSourceFields = hideSourceFields;
+        return this;
+    }
+
     /**
      * Rewrites this search source builder into its primitive form. e.g. by
      * rewriting the QueryBuilder. If the builder did not change the identity

server/src/main/java/org/elasticsearch/search/fetch/subphase/FetchSourceContext.java

@@ -13,8 +13,10 @@
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.util.ArrayUtils;
 import org.elasticsearch.core.Booleans;
 import org.elasticsearch.core.Nullable;
+import org.elasticsearch.index.shard.IndexShard;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.search.lookup.SourceFilter;
 import org.elasticsearch.xcontent.ParseField;
@@ -52,6 +54,31 @@ public static FetchSourceContext of(boolean fetchSource, @Nullable String[] incl
         return new FetchSourceContext(fetchSource, includes, excludes);
     }
 
+    public static FetchSourceContext of(FetchSourceContext original, IndexShard indexShard) {
+        // TODO: Delegate name retrieval to InferencerFieldMapper
+        String[] inferenceFields = indexShard.mapperService()
+            .mappingLookup()
+            .inferenceFields()
+            .keySet()
+            .stream()
+            .map(s -> s + ".inference")
+            .toArray(String[]::new);
+        if (inferenceFields.length == 0) {
+            return original;
+        }
+        if (original == null) {
+            return FetchSourceContext.of(true, null, inferenceFields);
+        }
+        if (original.includes() == null || original.includes().length == 0) {
+            return FetchSourceContext.of(
+                original.fetchSource(),
+                original.includes(),
+                ArrayUtils.concat(original.excludes(), inferenceFields)
+            );
+        }
+        return original;
+    }
+
     public static FetchSourceContext readFrom(StreamInput in) throws IOException {
         final boolean fetchSource = in.readBoolean();
         final String[] includes = in.readStringArray();