[server] Switch back to PubSubPosition based reads with offset as fallback

[sushantmane]

Switch back to PubSubPosition based reads with offset as fallback

Code changes

• Added new code behind a config. If so list the config names and their default values in the PR description.
• Introduced new log lines.
  • Confirmed if logs need to be rate limited to avoid excessive logging.

Concurrency-Specific Checks

Both reviewer and PR author to verify

• Code has no race conditions or thread safety issues.
• Proper synchronization mechanisms (e.g., synchronized, RWLock) are used where needed.
• No blocking calls inside critical sections that could lead to deadlocks or performance degradation.
• Verified thread-safe collections are used (e.g., ConcurrentHashMap, CopyOnWriteArrayList).
• Validated proper exception handling in multi-threaded code to avoid silent thread termination.

How was this PR tested?

• New unit tests added.
• New integration tests added.
• Modified or extended existing tests.
• Verified backward compatibility (if applicable).

Does this PR introduce any user-facing or breaking changes?

• No. You can skip the rest of this section.
• Yes. Clearly explain the behavior change and its impact.

[Copilot]

Pull Request Overview

This PR removes the getPubSubPositionString method and its associated test, replacing its usage with direct calls to pubSubPositionDeserializer.toPosition(). The key changes enable better position comparison by using actual PubSubPosition objects rather than numeric offsets, and utilize the deserializePositionWithOffsetFallback method for safer deserialization with fallback logic.

• Removes PubSubUtil.getPubSubPositionString utility method and its test
• Replaces numeric offset comparisons with proper position comparisons using diffPosition and object equality
• Updates deserializePositionWithOffsetFallback to remove the offset > 0 guard condition
• Integrates proper position deserialization with fallback in extractUpstreamPosition

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
PubSubUtil.java	Removes getPubSubPositionString utility method
PubSubUtilTest.java	Removes test coverage for getPubSubPositionString
OffsetRecord.java	Removes unused import and updates deserializePositionWithOffsetFallback condition
KafkaTopicDumper.java	Replaces getPubSubPositionString with direct toPosition calls
StoreIngestionTask.java	Updates position deserialization condition and integrates fallback in extractUpstreamPosition
StoreIngestionTaskTest.java	Changes test assertions to use full position equality instead of numeric offset comparison
PartitionTracker.java	Replaces getPubSubPositionString with direct toPosition call
LeaderFollowerStoreIngestionTask.java	Replaces numeric offset comparisons with proper position comparisons using diffPosition and symbolic position checks

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[Copilot]

Potential NullPointerException when leaderMetadata.upstreamPubSubPosition is null. The toPosition method throws an IllegalArgumentException when passed a null ByteBuffer. Add a null check for upstreamPubSubPosition or use a nested ternary to handle this case: leaderMetadata == null || leaderMetadata.upstreamPubSubPosition == null ? \"-\" : pubSubPositionDeserializer.toPosition(leaderMetadata.upstreamPubSubPosition)

Suggested change

	leaderMetadata == null ? "-" : pubSubPositionDeserializer.toPosition(leaderMetadata.upstreamPubSubPosition),
	(leaderMetadata == null || leaderMetadata.upstreamPubSubPosition == null) ? "-" : pubSubPositionDeserializer.toPosition(leaderMetadata.upstreamPubSubPosition),

[Copilot]

Potential NullPointerException when leaderMetadata.upstreamPubSubPosition is null. The toPosition method throws an IllegalArgumentException when passed a null ByteBuffer. Add a null check for upstreamPubSubPosition or use a nested ternary to handle this case: leaderMetadata == null || leaderMetadata.upstreamPubSubPosition == null ? \"-\" : pubSubPositionDeserializer.toPosition(leaderMetadata.upstreamPubSubPosition)

Suggested change

	leaderMetadata == null ? "-" : pubSubPositionDeserializer.toPosition(leaderMetadata.upstreamPubSubPosition),
	leaderMetadata == null || leaderMetadata.upstreamPubSubPosition == null ? "-" : pubSubPositionDeserializer.toPosition(leaderMetadata.upstreamPubSubPosition),

[Copilot]

Potential NullPointerException when upstreamPubSubPosition is null. The toPosition method throws an IllegalArgumentException when passed a null ByteBuffer. Consider adding a null check or using a defensive fallback similar to other parts of the codebase: upstreamPubSubPosition == null ? \"-\" : pubSubPositionDeserializer.toPosition(upstreamPubSubPosition)

Suggested change

	pubSubPositionDeserializer
	.toPosition(consumerRecord.getValue().leaderMetadataFooter.upstreamPubSubPosition))
	consumerRecord.getValue().leaderMetadataFooter.upstreamPubSubPosition == null
	? "-"
	: pubSubPositionDeserializer.toPosition(consumerRecord.getValue().leaderMetadataFooter.upstreamPubSubPosition))

[Copilot]

Removing the offset > 0 check means that this condition will now fire even when offset is 0 or negative. This could be intentional for handling edge cases, but it changes the behavior for positions at offset 0. Consider documenting why the guard was removed or verifying that positions at offset 0 should be subject to this fallback logic.

[Copilot]

Removing the offset > 0 check means that this condition will now fire even when offset is 0 or negative. This could be intentional for handling edge cases, but it changes the behavior for positions at offset 0. Consider documenting why the guard was removed or verifying that positions at offset 0 should be subject to this fallback logic.

Suggested change

	if (position.getNumericOffset() < offset) {
	if (offset > 0 && position.getNumericOffset() < offset) {

[github-actions]

Hi there. This pull request has been inactive for 30 days. To keep our review queue healthy, we plan to close it in 7 days unless there is new activity. If you are still working on this, please push a commit, leave a comment, or convert it to draft to signal intent. Thank you for your time and contributions.