fix: PubSubMessage leak on MessageDispatcher (#1197)

Author: labianchin

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/AckReplyConsumerImpl.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.cloud.pubsub.v1;
+
+import com.google.api.core.SettableApiFuture;
+
+public class AckReplyConsumerImpl implements AckReplyConsumer {
+  final SettableApiFuture<MessageDispatcher.AckReply> ackReplySettableApiFuture;
+
+  public AckReplyConsumerImpl(
+      final SettableApiFuture<MessageDispatcher.AckReply> ackReplySettableApiFuture) {
+    this.ackReplySettableApiFuture = ackReplySettableApiFuture;
+  }
+
+  @Override
+  public void ack() {
+    ackReplySettableApiFuture.set(MessageDispatcher.AckReply.ACK);
+  }
+
+  @Override
+  public void nack() {
+    ackReplySettableApiFuture.set(MessageDispatcher.AckReply.NACK);
+  }
+}

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/AckReplyConsumerWithResponseImpl.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.cloud.pubsub.v1;
+
+import com.google.api.core.SettableApiFuture;
+import java.util.concurrent.Future;
+
+public class AckReplyConsumerWithResponseImpl implements AckReplyConsumerWithResponse {
+  final SettableApiFuture<MessageDispatcher.AckReply> ackReplySettableApiFuture;
+  final SettableApiFuture<AckResponse> messageFuture;
+
+  public AckReplyConsumerWithResponseImpl(
+      SettableApiFuture<MessageDispatcher.AckReply> ackReplySettableApiFuture,
+      SettableApiFuture<AckResponse> messageFuture) {
+    this.ackReplySettableApiFuture = ackReplySettableApiFuture;
+    this.messageFuture = messageFuture;
+  }
+
+  @Override
+  public Future<AckResponse> ack() {
+    ackReplySettableApiFuture.set(MessageDispatcher.AckReply.ACK);
+    return messageFuture;
+  }
+
+  @Override
+  public Future<AckResponse> nack() {
+    ackReplySettableApiFuture.set(MessageDispatcher.AckReply.NACK);
+    return messageFuture;
+  }
+}

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/MessageDispatcher.java

@@ -35,7 +35,6 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
@@ -434,33 +433,11 @@ public void run() {
                 SettableApiFuture<AckResponse> messageFuture =
                     ackHandler.getMessageFutureIfExists();
                 final AckReplyConsumerWithResponse ackReplyConsumerWithResponse =
-                    new AckReplyConsumerWithResponse() {
-                      @Override
-                      public Future<AckResponse> ack() {
-                        ackReplySettableApiFuture.set(AckReply.ACK);
-                        return messageFuture;
-                      }
-
-                      @Override
-                      public Future<AckResponse> nack() {
-                        ackReplySettableApiFuture.set(AckReply.NACK);
-                        return messageFuture;
-                      }
-                    };
+                    new AckReplyConsumerWithResponseImpl(ackReplySettableApiFuture, messageFuture);
                 receiverWithAckResponse.receiveMessage(message, ackReplyConsumerWithResponse);
               } else {
                 final AckReplyConsumer ackReplyConsumer =
-                    new AckReplyConsumer() {
-                      @Override
-                      public void ack() {
-                        ackReplySettableApiFuture.set(AckReply.ACK);
-                      }
-
-                      @Override
-                      public void nack() {
-                        ackReplySettableApiFuture.set(AckReply.NACK);
-                      }
-                    };
+                    new AckReplyConsumerImpl(ackReplySettableApiFuture);
                 receiver.receiveMessage(message, ackReplyConsumer);
               }
             } catch (Exception e) {