fix: Message ordering fix for #1889 (#1903)

* chore: change assignees for issues and PRs to michaelpri10 * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * fix: Revert PR#1807 and use a LinkedHasMap in the MessageDispatcher * fix: Make processedReceivedMessages thread-safe * fix: Only synchronize on the outstandingReceipts object in the MessageDispatcher --------- Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: michaelpri10

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

@@ -31,6 +31,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -92,8 +93,8 @@ class MessageDispatcher {
  private final LinkedBlockingQueue<AckRequestData> pendingAcks = new LinkedBlockingQueue<>();
  private final LinkedBlockingQueue<AckRequestData> pendingNacks = new LinkedBlockingQueue<>();
  private final LinkedBlockingQueue<AckRequestData> pendingReceipts = new LinkedBlockingQueue<>();
- private final ConcurrentMap<String, ReceiptCompleteData> outstandingReceipts =
- new ConcurrentHashMap<String, ReceiptCompleteData>();
+ private final LinkedHashMap<String, ReceiptCompleteData> outstandingReceipts =
+ new LinkedHashMap<String, ReceiptCompleteData>();
  private final AtomicInteger messageDeadlineSeconds = new AtomicInteger();
  private final AtomicBoolean extendDeadline = new AtomicBoolean(true);
  private final Lock jobLock;
@@ -397,7 +398,9 @@ void processReceivedMessages(List<ReceivedMessage> messages) {
  if (this.exactlyOnceDeliveryEnabled.get()) {
  // For exactly once deliveries we don't add to outstanding batch because we first
  // process the receipt modack. If that is successful then we process the message.
- outstandingReceipts.put(message.getAckId(), new ReceiptCompleteData(outstandingMessage));
+ synchronized (outstandingReceipts) {
+ outstandingReceipts.put(message.getAckId(), new ReceiptCompleteData(outstandingMessage));
+ }
  } else if (pendingMessages.putIfAbsent(message.getAckId(), ackHandler) != null) {
  // putIfAbsent puts ackHandler if ackID isn't previously mapped, then return the
  // previously-mapped element.
@@ -417,33 +420,36 @@ void processReceivedMessages(List<ReceivedMessage> messages) {
  }
 
  void notifyAckSuccess(AckRequestData ackRequestData) {
-
- if (outstandingReceipts.containsKey(ackRequestData.getAckId())) {
- outstandingReceipts.get(ackRequestData.getAckId()).notifyReceiptComplete();
- List<OutstandingMessage> outstandingBatch = new ArrayList<>();
-
- for (Iterator<Entry<String, ReceiptCompleteData>> it =
- outstandingReceipts.entrySet().iterator();
- it.hasNext(); ) {
- Map.Entry<String, ReceiptCompleteData> receipt = it.next();
- // If receipt is complete then add to outstandingBatch to process the batch
- if (receipt.getValue().isReceiptComplete()) {
- it.remove();
- if (pendingMessages.putIfAbsent(
- receipt.getKey(), receipt.getValue().getOutstandingMessage().ackHandler)
- == null) {
- outstandingBatch.add(receipt.getValue().getOutstandingMessage());
+ synchronized (outstandingReceipts) {
+ if (outstandingReceipts.containsKey(ackRequestData.getAckId())) {
+ outstandingReceipts.get(ackRequestData.getAckId()).notifyReceiptComplete();
+ List<OutstandingMessage> outstandingBatch = new ArrayList<>();
+
+ for (Iterator<Entry<String, ReceiptCompleteData>> it =
+ outstandingReceipts.entrySet().iterator();
+ it.hasNext(); ) {
+ Map.Entry<String, ReceiptCompleteData> receipt = it.next();
+ // If receipt is complete then add to outstandingBatch to process the batch
+ if (receipt.getValue().isReceiptComplete()) {
+ it.remove();
+ if (pendingMessages.putIfAbsent(
+ receipt.getKey(), receipt.getValue().getOutstandingMessage().ackHandler)
+ == null) {
+ outstandingBatch.add(receipt.getValue().getOutstandingMessage());
+ }
+ } else {
+ break;
  }
- } else {
- break;
  }
+ processBatch(outstandingBatch);
  }
- processBatch(outstandingBatch);
  }
  }
 
  void notifyAckFailed(AckRequestData ackRequestData) {
- outstandingReceipts.remove(ackRequestData.getAckId());
+ synchronized (outstandingReceipts) {
+ outstandingReceipts.remove(ackRequestData.getAckId());
+ }
  }
 
  private void processBatch(List<OutstandingMessage> batch) {