Inject NamedWriteableRegistry in AD node client

src/main/java/org/opensearch/ad/client/AnomalyDetectionNodeClient.java

@@ -17,12 +17,15 @@
 import org.opensearch.client.Client;
 import org.opensearch.core.action.ActionListener;
 import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 
 public class AnomalyDetectionNodeClient implements AnomalyDetectionClient {
     private final Client client;
+    private final NamedWriteableRegistry namedWriteableRegistry;
 
-    public AnomalyDetectionNodeClient(Client client) {
+    public AnomalyDetectionNodeClient(Client client, NamedWriteableRegistry namedWriteableRegistry) {
         this.client = client;
+        this.namedWriteableRegistry = namedWriteableRegistry;
     }
 
     @Override
@@ -46,14 +49,18 @@ public void getDetectorProfile(GetAnomalyDetectorRequest profileRequest, ActionL
 
     // We need to wrap AD-specific response type listeners around an internal listener, and re-generate the response from a generic
     // ActionResponse. This is needed to prevent classloader issues and ClassCastExceptions when executed by other plugins.
+    // Additionally, we need to inject the configured NamedWriteableRegistry so NamedWriteables (present in sub-fields of
+    // GetAnomalyDetectorResponse) are able to be re-serialized and prevent errors like the following:
+    // "can't read named writeable from StreamInput"
     private ActionListener<GetAnomalyDetectorResponse> getAnomalyDetectorResponseActionListener(
         ActionListener<GetAnomalyDetectorResponse> listener
     ) {
         ActionListener<GetAnomalyDetectorResponse> internalListener = ActionListener.wrap(getAnomalyDetectorResponse -> {
             listener.onResponse(getAnomalyDetectorResponse);
         }, listener::onFailure);
         ActionListener<GetAnomalyDetectorResponse> actionListener = wrapActionListener(internalListener, actionResponse -> {
-            GetAnomalyDetectorResponse response = GetAnomalyDetectorResponse.fromActionResponse(actionResponse);
+            GetAnomalyDetectorResponse response = GetAnomalyDetectorResponse
+                .fromActionResponse(actionResponse, this.namedWriteableRegistry);
             return response;
         });
         return actionListener;

src/main/java/org/opensearch/ad/transport/GetAnomalyDetectorResponse.java

@@ -22,6 +22,8 @@
 import org.opensearch.ad.model.EntityProfile;
 import org.opensearch.core.action.ActionResponse;
 import org.opensearch.core.common.io.stream.InputStreamStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.core.common.io.stream.OutputStreamStreamOutput;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.core.common.io.stream.StreamOutput;
@@ -218,16 +220,21 @@ public AnomalyDetector getDetector() {
         return detector;
     }
 
-    public static GetAnomalyDetectorResponse fromActionResponse(ActionResponse actionResponse) {
+    public static GetAnomalyDetectorResponse fromActionResponse(
+        ActionResponse actionResponse,
+        NamedWriteableRegistry namedWriteableRegistry
+    ) {
         if (actionResponse instanceof GetAnomalyDetectorResponse) {
             return (GetAnomalyDetectorResponse) actionResponse;
         }
 
-        try (ByteArrayOutputStream baos = new ByteArrayOutputStream(); OutputStreamStreamOutput osso = new OutputStreamStreamOutput(baos)) {
+        try {
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            OutputStreamStreamOutput osso = new OutputStreamStreamOutput(baos);
             actionResponse.writeTo(osso);
-            try (StreamInput input = new InputStreamStreamInput(new ByteArrayInputStream(baos.toByteArray()))) {
-                return new GetAnomalyDetectorResponse(input);
-            }
+            InputStreamStreamInput input = new InputStreamStreamInput(new ByteArrayInputStream(baos.toByteArray()));
+            NamedWriteableAwareStreamInput namedWriteableAwareInput = new NamedWriteableAwareStreamInput(input, namedWriteableRegistry);
+            return new GetAnomalyDetectorResponse(namedWriteableAwareInput);
         } catch (IOException e) {
             throw new UncheckedIOException("failed to parse ActionResponse into GetAnomalyDetectorResponse", e);
         }

src/test/java/org/opensearch/ad/client/AnomalyDetectionNodeClientTests.java

@@ -40,6 +40,7 @@
 import org.opensearch.client.Client;
 import org.opensearch.common.lucene.uid.Versions;
 import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.core.rest.RestStatus;
 import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.TermQueryBuilder;
@@ -64,7 +65,7 @@ public class AnomalyDetectionNodeClientTests extends HistoricalAnalysisIntegTest
     @Before
     public void setup() {
         clientSpy = spy(client());
-        adClient = new AnomalyDetectionNodeClient(clientSpy);
+        adClient = new AnomalyDetectionNodeClient(clientSpy, mock(NamedWriteableRegistry.class));
     }
 
     @Test

src/test/java/org/opensearch/ad/transport/GetAnomalyDetectorResponseTests.java

@@ -17,8 +17,11 @@
 import java.util.Collection;
 
 import org.opensearch.common.io.stream.BytesStreamOutput;
+import org.opensearch.core.action.ActionResponse;
 import org.opensearch.core.common.io.stream.NamedWriteableAwareStreamInput;
 import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.core.rest.RestStatus;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.test.InternalSettingsPlugin;
@@ -76,6 +79,21 @@ public void testSerializationWithJobAndTask() throws IOException {
         assertEquals(response.getDetector(), parsedResponse.getDetector());
     }
 
+    public void testFromActionResponse() throws IOException {
+        GetAnomalyDetectorResponse response = createGetAnomalyDetectorResponse(true, true);
+        BytesStreamOutput output = new BytesStreamOutput();
+        response.writeTo(output);
+        NamedWriteableAwareStreamInput input = new NamedWriteableAwareStreamInput(output.bytes().streamInput(), writableRegistry());
+
+        GetAnomalyDetectorResponse reserializedResponse = GetAnomalyDetectorResponse
+            .fromActionResponse((ActionResponse) response, writableRegistry());
+        assertEquals(response, reserializedResponse);
+
+        ActionResponse invalidActionResponse = new TestActionResponse(input);
+        assertThrows(Exception.class, () -> GetAnomalyDetectorResponse.fromActionResponse(invalidActionResponse, writableRegistry()));
+
+    }
+
     private GetAnomalyDetectorResponse createGetAnomalyDetectorResponse(boolean returnJob, boolean returnTask) throws IOException {
         GetAnomalyDetectorResponse response = new GetAnomalyDetectorResponse(
             randomLong(),
@@ -95,4 +113,17 @@ private GetAnomalyDetectorResponse createGetAnomalyDetectorResponse(boolean retu
         );
         return response;
     }
+
+    // A test ActionResponse class with an inactive writeTo class. Used to ensure exceptions
+    // are thrown when parsing implementations of such class.
+    private class TestActionResponse extends ActionResponse {
+        public TestActionResponse(StreamInput in) throws IOException {
+            super(in);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            return;
+        }
+    }
 }