ISSUE-6869: Negative acknowledgement doesn't remove the message id from UnAckedMessageTracker when message id is instance of BatchMessageIdImpl

[sijie]

Original Issue: apache#6869

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Describe the bug

The actual symptom was that when using the DLQ feature, the redelivery counts were not consistent in a use case where negative acknowledgements are used. Messages would get redelivered more times than the configured maxRedeliverCount on the DeadLetterPolicy.

I observed this type of log messages in the log output:

14:20:07.080 [pulsar-timer-4-1] WARN  o.a.p.c.impl.UnAckedMessageTracker - [ConsumerBase{subscription='Test-Subscriber', consumerName='f194e', topic='test-topic'}] 5 messages have timed-out

By debugging, I noticed that calling org.apache.pulsar.client.api.Consumer#negativeAcknowledge(org.apache.pulsar.client.api.MessageId) doesn't remove the message id from UnAckedMessageTracker when the message is instance of BatchMessageIdImpl.

Expected behavior

org.apache.pulsar.client.impl.UnAckedMessageTracker implementation should encapsulate the fact that the message id must be MessageIdImpl and not BatchMessageIdImpl.

Currently the logic to first convert a BatchMessageIdImpl is done on the calling side (examples: https://github.com/apache/pulsar/blob/de57ddd572dbc74529a56fee68c6be37bd35cf7c/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L521-L531 , https://github.com/apache/pulsar/blob/de57ddd572dbc74529a56fee68c6be37bd35cf7c/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L1155-L1164 )

Since the caller has to convert the message id before calling UnAckedMessageTracker add or remove methods, it seems that this leads to error prone usage of the UnAckedMessageTracker class. Currently the conversion to MessageIdImpl is missing in the negative acknowledgement method:
https://github.com/apache/pulsar/blob/de57ddd572dbc74529a56fee68c6be37bd35cf7c/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java#L556-L557

Work around

One workaround is to convert a possible BatchMessageIdImpl to MessageIdImpl before calling the negativeAcknowledge method. Something like this

   ...
   consumer.negativeAcknowledge(convertMessageIdForNack(message.getMessageId()));
   ...

    // workaround Pulsar bug regarding negative acknowledgements
    private static MessageId convertMessageIdForNack(MessageId messageId) {
        if (messageId instanceof BatchMessageIdImpl) {
            // use similar logic as there is in org.apache.pulsar.client.impl.NegativeAcksTracker#add
            BatchMessageIdImpl batchMessageId = (BatchMessageIdImpl) messageId;
            return new MessageIdImpl(batchMessageId.getLedgerId(), batchMessageId.getEntryId(),
                    batchMessageId.getPartitionIndex());
        } else {
            return messageId;
        }
    }