Make restApiVersion on XContentBuilder final

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

@@ -53,6 +53,24 @@ public static XContentBuilder builder(XContent xContent) throws IOException {
         return new XContentBuilder(xContent, new ByteArrayOutputStream());
     }
 
+    /**
+     * Create a new {@link XContentBuilder} using the given {@link XContent} content and RestApiVersion.
+     * <p>
+     * The builder uses an internal {@link ByteArrayOutputStream} output stream to build the content.
+     * </p>
+     *
+     * @param xContent the {@link XContent}
+     * @return a new {@link XContentBuilder}
+     * @throws IOException if an {@link IOException} occurs while building the content
+     */
+    public static XContentBuilder builder(XContent xContent, RestApiVersion restApiVersion) throws IOException {
+        return new XContentBuilder(xContent, new ByteArrayOutputStream(),
+            Collections.emptySet(),
+            Collections.emptySet(),
+            xContent.type().toParsedMediaType(),
+            restApiVersion);
+    }
+
     /**
      * Create a new {@link XContentBuilder} using the given {@link XContentType} xContentType and some inclusive and/or exclusive filters.
      * <p>
@@ -68,7 +86,7 @@ public static XContentBuilder builder(XContent xContent) throws IOException {
      */
     public static XContentBuilder builder(XContentType xContentType, Set<String> includes, Set<String> excludes) throws IOException {
         return new XContentBuilder(xContentType.xContent(), new ByteArrayOutputStream(), includes, excludes,
-            xContentType.toParsedMediaType());
+            xContentType.toParsedMediaType(), RestApiVersion.current());
     }
 
     private static final Map<Class<?>, Writer> WRITERS;
@@ -152,21 +170,23 @@ public interface HumanReadableTransformer {
      */
     private final OutputStream bos;
 
+    private final RestApiVersion restApiVersion;
+
+    private final ParsedMediaType responseContentType;
+
     /**
      * When this flag is set to true, some types of values are written in a format easier to read for a human.
      */
     private boolean humanReadable = false;
 
-    private RestApiVersion restApiVersion;
 
-    private ParsedMediaType responseContentType;
 
     /**
      * Constructs a new builder using the provided XContent and an OutputStream. Make sure
      * to call {@link #close()} when the builder is done with.
      */
     public XContentBuilder(XContent xContent, OutputStream bos) throws IOException {
-        this(xContent, bos, Collections.emptySet(), Collections.emptySet(), xContent.type().toParsedMediaType());
+        this(xContent, bos, Collections.emptySet(), Collections.emptySet(), xContent.type().toParsedMediaType(), RestApiVersion.current());
     }
     /**
      * Constructs a new builder using the provided XContent, an OutputStream and
@@ -175,7 +195,7 @@ public XContentBuilder(XContent xContent, OutputStream bos) throws IOException {
      * {@link #close()} when the builder is done with.
      */
     public XContentBuilder(XContentType xContentType, OutputStream bos, Set<String> includes) throws IOException {
-        this(xContentType.xContent(), bos, includes, Collections.emptySet(), xContentType.toParsedMediaType());
+        this(xContentType.xContent(), bos, includes, Collections.emptySet(), xContentType.toParsedMediaType(), RestApiVersion.current());
     }
 
     /**
@@ -191,10 +211,30 @@ public XContentBuilder(XContentType xContentType, OutputStream bos, Set<String>
      */
     public XContentBuilder(XContent xContent, OutputStream os, Set<String> includes, Set<String> excludes,
                            ParsedMediaType responseContentType) throws IOException {
+        this(xContent, os, includes, excludes, responseContentType, RestApiVersion.current());
+    }
+
+    /**
+     * Creates a new builder using the provided XContent, output stream and some inclusive and/or exclusive filters. When both exclusive and
+     * inclusive filters are provided, the underlying builder will first use exclusion filters to remove fields and then will check the
+     * remaining fields against the inclusive filters.
+     * Stores RestApiVersion to help steer the use of the builder depending on the version.
+     * @see #getRestApiVersion()
+     * <p>
+     * Make sure to call {@link #close()} when the builder is done with.
+     * @param os       the output stream
+     * @param includes the inclusive filters: only fields and objects that match the inclusive filters will be written to the output.
+     * @param excludes the exclusive filters: only fields and objects that don't match the exclusive filters will be written to the output.
+     * @param responseContentType  a content-type header value to be send back on a response
+     * @param restApiVersion a rest api version indicating with which version the XContent is compatible with.
+     */
+    public XContentBuilder(XContent xContent, OutputStream os, Set<String> includes, Set<String> excludes,
+                           ParsedMediaType responseContentType, RestApiVersion restApiVersion) throws IOException {
         this.bos = os;
         assert responseContentType != null : "generated response cannot be null";
         this.responseContentType = responseContentType;
         this.generator = xContent.createGenerator(bos, includes, excludes);
+        this.restApiVersion = restApiVersion;
     }
 
     public String getResponseContentTypeString() {
@@ -1006,16 +1046,6 @@ public XContentBuilder copyCurrentStructure(XContentParser parser) throws IOExce
         return this;
     }
 
-    /**
-     * Sets a version used for serialising a response compatible with a previous version.
-     * @param restApiVersion - indicates requested a version of API that the builder will be creating
-     */
-    public XContentBuilder withCompatibleVersion(RestApiVersion restApiVersion) {
-        assert this.restApiVersion == null : "restApiVersion has already been set";
-        Objects.requireNonNull(restApiVersion, "restApiVersion cannot be null");
-        this.restApiVersion = restApiVersion;
-        return this;
-    }
 
     /**
      * Returns a version used for serialising a response.

server/src/main/java/org/elasticsearch/rest/AbstractRestChannel.java

@@ -126,7 +126,7 @@ public XContentBuilder newBuilder(@Nullable XContentType requestContentType, @Nu
 
         XContentBuilder builder =
             new XContentBuilder(XContentFactory.xContent(responseContentType), unclosableOutputStream,
-                includes, excludes, responseMediaType);
+                includes, excludes, responseMediaType, request.getRestApiVersion());
         if (pretty) {
             builder.prettyPrint().lfAtEnd();
         }

server/src/main/java/org/elasticsearch/rest/RestController.java

@@ -268,7 +268,7 @@ private void dispatchRequest(RestRequest request, RestChannel channel, RestHandl
                 inFlightRequestsBreaker(circuitBreakerService).addWithoutBreaking(contentLength);
             }
             // iff we could reserve bytes for the request we need to send the response also over this channel
-            responseChannel = new ResourceHandlingHttpChannel(channel, circuitBreakerService, contentLength, restApiVersion);
+            responseChannel = new ResourceHandlingHttpChannel(channel, circuitBreakerService, contentLength);
             // TODO: Count requests double in the circuit breaker if they need copying?
             if (handler.allowsUnsafeBuffers() == false) {
                 request.ensureSafeBuffers();
@@ -492,40 +492,33 @@ private static final class ResourceHandlingHttpChannel implements RestChannel {
         private final RestChannel delegate;
         private final CircuitBreakerService circuitBreakerService;
         private final int contentLength;
-        private final RestApiVersion restApiVersion;
         private final AtomicBoolean closed = new AtomicBoolean();
 
-        ResourceHandlingHttpChannel(RestChannel delegate, CircuitBreakerService circuitBreakerService, int contentLength,
-                                    RestApiVersion restApiVersion) {
+        ResourceHandlingHttpChannel(RestChannel delegate, CircuitBreakerService circuitBreakerService, int contentLength) {
             this.delegate = delegate;
             this.circuitBreakerService = circuitBreakerService;
             this.contentLength = contentLength;
-            this.restApiVersion = restApiVersion;
         }
 
         @Override
         public XContentBuilder newBuilder() throws IOException {
-            return delegate.newBuilder()
-                .withCompatibleVersion(restApiVersion);
+            return delegate.newBuilder();
         }
 
         @Override
         public XContentBuilder newErrorBuilder() throws IOException {
-            return delegate.newErrorBuilder()
-                .withCompatibleVersion(restApiVersion);
+            return delegate.newErrorBuilder();
         }
 
         @Override
         public XContentBuilder newBuilder(@Nullable XContentType xContentType, boolean useFiltering) throws IOException {
-            return delegate.newBuilder(xContentType, useFiltering)
-                .withCompatibleVersion(restApiVersion);
+            return delegate.newBuilder(xContentType, useFiltering);
         }
 
         @Override
         public XContentBuilder newBuilder(XContentType xContentType, XContentType responseContentType, boolean useFiltering)
             throws IOException {
-            return delegate.newBuilder(xContentType, responseContentType, useFiltering)
-                .withCompatibleVersion(restApiVersion);
+            return delegate.newBuilder(xContentType, responseContentType, useFiltering);
         }
 
         @Override

server/src/test/java/org/elasticsearch/action/DocWriteResponseTests.java

@@ -110,23 +110,20 @@ public void testTypeWhenCompatible() throws IOException {
         ) {
             // DocWriteResponse is abstract so we have to sneak a subclass in here to test it.
         };
-        try (XContentBuilder builder = JsonXContent.contentBuilder()) {
-            builder.withCompatibleVersion(RestApiVersion.V_7);
+        try (XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent, RestApiVersion.V_7)) {
             response.toXContent(builder, ToXContent.EMPTY_PARAMS);
 
             try (XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(builder))) {
                 assertThat(parser.map(), hasEntry(MapperService.TYPE_FIELD_NAME, MapperService.SINGLE_MAPPING_NAME));
             }
         }
 
-        try (XContentBuilder builder = JsonXContent.contentBuilder()) {
-            builder.withCompatibleVersion(RestApiVersion.V_8);
+        try (XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent, RestApiVersion.V_8)) {
             response.toXContent(builder, ToXContent.EMPTY_PARAMS);
 
             try (XContentParser parser = createParser(JsonXContent.jsonXContent, BytesReference.bytes(builder))) {
                 assertThat(parser.map(), not(hasKey(MapperService.TYPE_FIELD_NAME)));
             }
         }
     }
-
 }

server/src/test/java/org/elasticsearch/index/get/GetResultTests.java

@@ -96,8 +96,7 @@ public void testToCompatibleXContent() throws IOException {
                 singletonList("value1"))), singletonMap("field1", new DocumentField("metafield",
                 singletonList("metavalue"))));
 
-            try (XContentBuilder builder = JsonXContent.contentBuilder()) {
-                builder.withCompatibleVersion(RestApiVersion.V_7);
+            try (XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent, RestApiVersion.V_7)) {
                 getResult.toXContent(builder, ToXContent.EMPTY_PARAMS);
                 String output = Strings.toString(builder);
                 assertEquals("{\"_index\":\"index\",\"_type\":\"_doc\",\"_id\":\"id\",\"_version\":1,\"_seq_no\":0,\"_primary_term\":1," +
@@ -108,8 +107,7 @@ public void testToCompatibleXContent() throws IOException {
         {
             GetResult getResult = new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null);
 
-            try (XContentBuilder builder = JsonXContent.contentBuilder()) {
-                builder.withCompatibleVersion(RestApiVersion.V_7);
+            try (XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent, RestApiVersion.V_7)) {
                 getResult.toXContent(builder, ToXContent.EMPTY_PARAMS);
                 String output = Strings.toString(builder);
                 assertEquals("{\"_index\":\"index\",\"_type\":\"_doc\",\"_id\":\"id\",\"found\":false}", output);

x-pack/plugin/eql/src/main/java/org/elasticsearch/xpack/eql/action/EqlSearchResponse.java

@@ -204,7 +204,7 @@ private static final class Fields {
 
         @SuppressWarnings("unchecked")
         private static final ConstructingObjectParser<Event, Void> PARSER =
-                new ConstructingObjectParser<>("eql/search_response_event", true, 
+                new ConstructingObjectParser<>("eql/search_response_event", true,
                     args -> new Event((String) args[0], (String) args[1], (BytesReference) args[2], (Map<String, DocumentField>) args[3]));
 
         static {

x-pack/plugin/eql/src/test/java/org/elasticsearch/xpack/eql/action/EqlSearchResponseTests.java

@@ -233,7 +233,7 @@ protected EqlSearchResponse mutateInstanceForVersion(EqlSearchResponse instance,
                 mutatedSequences.add(new Sequence(s.joinKeys(), mutateEvents(s.events(), version)));
             }
         }
-        
+
         return new EqlSearchResponse(new EqlSearchResponse.Hits(mutatedEvents, mutatedSequences, instance.hits().totalHits()),
             instance.took(), instance.isTimeout(), instance.id(), instance.isRunning(), instance.isPartial());
     }