[Bug] POP retry response recoding uses the wrong record after a multi-message batch

[Aias00]

Reproduction\n\nWhen POP returns more than one normal message before a retry-topic result, PopConsumerContext stores one GetMessageResult per fetch result but flattens PopConsumerRecord entries per message.\n\nPopConsumerService later iterates getMessageResultList by result index and looks up popConsumerRecordList with the same index. After a multi-message result, that index points into the preceding batch instead of to the first record for the current result.\n\nWith popResponseReturnActualRetryTopic enabled, a retry result can therefore be treated as a normal result and skip retry-message recoding.\n\n## Expected behavior\n\nEach fetched GetMessageResult must use the first PopConsumerRecord that belongs to that result when deciding whether to recode retry messages.\n\n## Regression test\n\nPopConsumerServiceTest.popAsyncRecodeRetryMessagesAfterMultiMessageNormalResultTest fails on current develop.

[RockteMQ-AI]

Issue Evaluation

Category: bug | Status: Confirmed

The reported index misalignment in PopConsumerService has been verified against the current develop branch.

Root Cause: In PopConsumerService.java (line ~434-436), the loop iterates getMessageResultList by index i and looks up popConsumerRecordList.get(i) with the same index. When a single fetch result contains multiple messages, the record list has one entry per message while the result list has one entry per fetch — so after a multi-message batch, index i points into the wrong batch.

Impact: With popResponseReturnActualRetryTopic enabled, a retry result can be misidentified as normal and skip retry-message recoding, leading to incorrect message routing.

Severity: High — affects POP consumption correctness under multi-message batch scenarios.

Verified at: broker/src/main/java/org/apache/rocketmq/broker/pop/PopConsumerService.java:434-446

An automated fix proposal can be generated. Reply /approve to proceed with PR generation.

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Automated evaluation by RockteMQ-AI