[zhongkechen]

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Issue Link, if available

Extracted as an independent fix from #721.

Description

The successful-handler path serialized the result and checkpointed an oversized payload before firing onInvocationEnd. If serialization or the checkpoint failed, plugins received a start hook without the matching end hook. That leaves telemetry unfinished: buffered exporters are not flushed and OTel spans are not ended.

Capture result-delivery failures, unwrap CompletionException from a failed checkpoint, fire onInvocationEnd with RETRYING, then rethrow the original failure. The result passed to the hook remains null because it was not delivered. No public API changes.

Demo/Screenshots

Not applicable.

Checklist

• I have filled out every section of the PR template
• I have thoroughly tested this change

Testing

Unit Tests

Added a real oversized-result checkpoint failure test through DurableExecutor and the checkpoint batcher. It verifies the EXECUTION/SUCCEED request, exactly one paired start/end hook, RETRYING, a null undelivered result, and the same original exception at the hook and caller.

DurableExecutionTest: 11 tests passed. Isolated mutation checks confirm the new test fails if either the end-hook fix or exception unwrapping is removed.

Integration Tests

The local-runner serialization failure regression remains covered by PluginIntegrationTest (34 tests passed). The simulated wrapped-SerDes test was replaced by the actual checkpoint test above. Formatting checks passed.

Examples

Not applicable.

[github-actions]

Codex AI review

No actionable findings. Residual risk is limited to uncommon throwable variants not explicitly covered by the added serialization and checkpoint-failure tests.

Reviewed commit 77d67a9a5d7b8cdc059f3201c5c51e876cb9dea6. Workflow run