[PR] THRIFT-6082: Avoid reentrant Condition.notify() in TProcessPoolServer test shutdown [thrift]

["Jens-G (via GitHub)" <gi...@apache.org>]

Jens-G opened a new pull request, #3633:
URL: https://github.com/apache/thrift/pull/3633

   ## Summary
   - `test/py/TestServer.py` shuts the `TProcessPoolServer` test flavor down via a `signal.alarm(4)` handler that terminates the worker processes and then calls `server.stop()`.
   - `TProcessPoolServer.serve()` blocks its main thread in `multiprocessing.Condition.wait()`. Since Python signal handlers run synchronously nested inside the interrupted thread, the handler reenters on the *same* thread that's parked in `wait()`. `stop()`'s `Condition.notify()` then blocks forever waiting for a wake acknowledgement that only the (now unreachable) interrupted `wait()` call could ever send — a permanent deadlock.
   - This reproduced deterministically (10/10 runs, both `fork` and `spawn` multiprocessing start methods) against the unmodified library, and matches a `lib-python-macos` CI job that hung until GitHub Actions' 6-hour ceiling (see #3632 for the accompanying CI timeout).
   - Fix: terminate the workers and exit the process directly (`os._exit(0)`) instead of coordinating through the `Condition`, since the process is being torn down anyway. Verified the fix with 30/30 clean exits (20x `spawn`, 10x `fork`) where the original code hung 15/15.
   - JIRA: THRIFT-6082
   
   ## Test plan
   - [x] `python3 -m py_compile test/py/TestServer.py`
   - [x] `flake8` clean (project `.flake8` config)
   - [x] Isolated repro harness against the real `TProcessPoolServer`/`TestServer.py` shutdown logic: 15/15 hangs before the fix, 30/30 clean exits after
   - [ ] CI (`lib-python`, `lib-python-macos`) green on this PR
   
   Co-Authored-By: Claude Sonnet 5 <no...@anthropic.com>


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Re: [PR] THRIFT-6082: Avoid reentrant Condition.notify() in TProcessPoolServer test shutdown [thrift]

["Jens-G (via GitHub)" <gi...@apache.org>]

Jens-G merged PR #3633:
URL: https://github.com/apache/thrift/pull/3633


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