[bubanko]

Summary

Changes

Replicate the thread-safe BatchItemFailure collection implementation from the processBatchInParallel(event, context) method to the overloaded variant that additionally accepting an executor.

Apply this fix to all three BatchMessageHandler implementations.

Using a shared, unsynchronized ArrayList to collect BatchItemFailure instances can lead to lost failure items or cause a worker thread to fail with an ArrayOutOfBoundsException due to concurrent modifications corrupting the list's internals state.

Issue number: Fixes #2712

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[bubanko]

I presume duplication is not a blocker for this—the reported code blocks were already duplicates, and resolving this would require a refactor effort which would be too big for a "fix" PR.

@phipag, can we move forward with this or would you like me to try and resolve the duplication?

[phipag]

Hey @bubanko,

the Sonar duplication is acceptable here. But can you take a look at the .toList() findings and also the Remove this unused method parameter "context".?

https://sonarcloud.io/project/issues?id=aws-powertools_powertools-lambda-java&pullRequest=2735&s=IMPACT_RANK&sinceLeakPeriod=true&issueStatuses=OPEN%2CCONFIRMED

[bubanko]

Ah, yes. I don't know why I though the .toList() is a false positive 🤦

As for the unused context parameter—I can remove them, but those methods are untouched by this PR ATM.

[sonarqubecloud]

Quality Gate failed

Failed conditions
10.5% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

[phipag]

Thanks @bubanko,

I tested this again locally:

• Unit tests fail before the code change (not consistently but consistently enough for a regression test)
• E2E tests pass (I ran this against my AWS account)

This PR is ready to be merged. Thank you for your contribution!