fix(a2a): clean up cancellation tasks and Redis pubsub

[adityat210]

Summary

• close the Redis pubsub used by the A2A cancellation watcher
• cancel and await both child tasks during every exit path
• add regression coverage for normal completion and caller-driven cancellation

Problem

The cancellable decorator spawned an execution task and a cancellation watcher, but its cleanup only deleted the cancellation flag. On normal completion it cancelled the watcher without awaiting it, and when the wrapper itself was cancelled it left both child tasks running. The Redis watcher also created a dedicated pubsub connection without closing it.

That could retain one watcher task and one pubsub connection after a normal Redis-backed execution, or leave the execution task, watcher, and pubsub alive after caller cancellation.

Fix

The wrapper now owns the complete lifecycle of both child tasks in a finally block: unfinished tasks are cancelled and both are awaited with asyncio.gather(..., return_exceptions=True) before the cancellation flag is removed. The Redis watcher closes pubsub in its own finally block and logs connection-level close failures without masking the task result.

This follows Python's asyncio cancellation guidance to perform cleanup in finally, and redis-py's explicit async resource cleanup guidance.

No public API or cancellation semantics change.

Impact

Eliminates up to three residual async resources per caller-cancelled Redis-backed execution (the execution task, watcher task, and pubsub connection), and two after normal Redis-backed completion (watcher plus pubsub).

Tests

• pytest -n 0 lib/crewai/tests/a2a/utils/test_task.py -q — 18 passed
• pytest -n 0 lib/crewai/tests/a2a/utils -q — 39 passed
• ruff format --check — passed
• ruff check — passed
• targeted mypy — passed
• git diff --check — passed

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 6a421497-1727-473a-b07f-9716a4c77464

📥 Commits

Reviewing files that changed from the base of the PR and between c8f441c and 8659424.

📒 Files selected for processing (2)

• lib/crewai/src/crewai/a2a/utils/task.py
• lib/crewai/tests/a2a/utils/test_task.py

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📝 Walkthrough

Walkthrough

The cancellation wrapper now closes Redis pub/sub connections reliably. It also cancels and gathers both execution and watcher tasks. Tests cover successful cleanup, wrapper cancellation, and continued CancelledError behavior.

Changes

Cancellation cleanup

Layer / File(s)	Summary
Redis watcher resource cleanup lib/crewai/src/crewai/a2a/utils/task.py, lib/crewai/tests/a2a/utils/test_task.py	The Redis watcher closes its pub/sub connection in a finally block and logs OSError or ConnectionError failures. Tests verify cleanup after successful execution.
Coordinated task cancellation lib/crewai/src/crewai/a2a/utils/task.py, lib/crewai/tests/a2a/utils/test_task.py	Cancellation now stops unfinished execution and watcher tasks, then gathers both with exception collection. Tests verify wrapped coroutine cleanup and continued CancelledError behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the cleanup of A2A cancellation tasks and Redis pubsub resources.
Description check	✅ Passed	The description directly explains the cancellation cleanup changes, Redis pubsub cleanup, regression tests, and validation results.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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