fix(core): macOS fallback for the os.waitid ownership probe (#1656) - #1657
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…h#1656) CPython on macOS does not expose os.waitid (HAVE_WAITID is not set), so debpalash#1635's WNOWAIT 'exited but unreaped' probe raised AttributeError on every poll after the first spawn: second+ TTS requests 500'd and the sidecar idle reaper errored, on all macOS builds (desktop and server). Darwin's underlying waitid(2) cannot stand in either: with WNOHANG it reports running children as eligible with junk state, so the probe semantics are unimplementable from Python there. The fallback reaps with waitpid(WNOHANG) instead: real exit codes, ECHILD refusal preserved for foreign reapers (a leader reaped through our own Popen reports its known code instead of refusing), and the lost pre-reap group kill is covered by the supervisor's control-pipe EOF, which already terminates the nested group per the debpalash#1635 design. Linux behavior is unchanged (hasattr(os, 'waitid') branch). Tests simulate the macOS platform (os.waitid removed) and pin: running child polls None, real exit codes surface, kill/wait works, reaping by our own handle reports the code, a foreign reaper is refused.
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Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review. 📝 WalkthroughWalkthroughChangesThe change adds a macOS waitid fallback
Estimated code review effort: 3 (Moderate) | ~20 minutes Merge Risk: ⚪ Minimal · up to The macOS process-ownership fallback preserves existing ownership checks and cleanup behavior, with targeted and broader tests covering the changed paths; no actionable merge-blocking risk remains beyond normal checks and review. Suggested reviewers: 🚥 Pre-merge checks | ✅ 8 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (8 passed)
Full details: Description checkExplanation The description clearly explains the bug, implementation, testing, and linked issue. It does not use the repository headings or complete the Type and Checklist sections, but it contains the required substantive information. Full details: Docstring CoverageExplanation Docstring coverage is 23.08% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 13 functions across 2 files. (1 skipped: 1 unsupported.) Full details: Cross-Platform Default ParityExplanation The change preserves the default lifecycle behavior across the target platforms. Linux keeps the existing Full details: I18n Completeness (21 Locales)Explanation No frontend files changed in the PR range. The diff contains only CHANGELOG.md and backend files, so it introduces no frontend t('...') keys or hardcoded frontend user-facing strings that bypass i18n. The repository contains all 21 locale files, but no locale comparison is required for this PR. Full details: Local-First GuaranteeExplanation PASS — The PR changes only local subprocess ownership and adds local tests plus a changelog entry. The added code uses Full details: Backward CompatibilityExplanation PASS — The PR changes only
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Inline comments:
In `@backend/core/contained_subprocess.py`:
- Around line 164-169: In the AttributeError fallback before process-group
signaling, use waitpid(self.pid, WNOHANG) to verify the leader is still owned
and running; treat ChildProcessError and an already-exited leader as refusal
conditions and return without calling os.killpg. Add a regression test that
externally reaps the leader and verifies kill() does not invoke os.killpg.
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| Filename | Overview |
|---|---|
| backend/core/contained_subprocess.py | Adds the no-waitid POSIX fallback and ownership checks without an eligible blocking defect. |
| backend/tests/test_contained_subprocess_waitid_fallback.py | Adds focused regression tests using fixed, non-shell subprocess arguments. |
| CHANGELOG.md | Adds a correctly formatted single-line entry for the macOS fix. |
Reviews (3): Last reviewed commit: "fix(core): prove child ownership before ..." | Re-trigger Greptile
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Two follow-ups:
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… path) Review follow-up (CodeRabbit on debpalash#1657): without the waitid ECHILD probe, kill()/terminate() could reach killpg after a foreign reaper took the leader. kill(pid, 0) now refuses once the pid is fully gone (ESRCH = reaped); the residual reused-pid window is documented as inherent to the platform.
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Inline comments:
In `@backend/core/contained_subprocess.py`:
- Around line 166-175: Update the signaling guard around os.kill and killpg to
verify child ownership with waitpid(self.pid, os.WNOHANG) before signaling;
return when waitpid raises ChildProcessError or reports a reaped child, while
preserving handling for ProcessLookupError. Add a regression test using a mocked
reused PID that fails before the change and confirms killpg is not called
afterward.
Apply the same fix in
`@backend/tests/test_contained_subprocess_waitid_fallback.py` around lines 104 -
116: The test-specific assertion is included in the consolidated remediation.
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2 participants
Fixes #1656.
What
#1635's
OwnedPopenprobes "exited but not yet reaped" withos.waitid(P_PID, …, WEXITED|WNOHANG| WNOWAIT). CPython on macOS does not exposeos.waitidat all (HAVE_WAITIDis not set in its builds), so on macOS every poll after the first spawn raisedAttributeError: second+ synthesis requests 500 withmodule 'os' has no attribute waitid', and the sidecar idle reaper errors. Repro in the issue: first request 200, second request 500 in 0.04s.This PR keeps the waitid path on Linux (byte-identical behavior) and adds a macOS fallback:
_posix_exited_reaping():waitpid(WNOHANG)probe that reaps the wrapper — returns the real exit code when exited,Nonewhile running, and refuses (ECHILD→ no signal) for foreign reapers. A leader reaped through our own Popen reports its known code instead of refusing (own-handle reaping is not the foreign-reaper case the refusal guards)._signal_owned_grouptolerates the missing attribute (the_returncodechecks in terminate/kill plusProcessLookupErrorbound the window).Why not ctypes on Darwin's waitid(2)
I tried it before falling back: Darwin's
waitidwithWNOHANG|WNOWAITreports running children as eligible with junk siginfo (verified empirically: running child →si_code=CLD_EXITED, si_status=0), so the Linux "si_pid != 0means waited" reading is wrong there and the probe cannot be implemented over it.sysctl KERN_PROC_PIDwas the other candidate; itsp_statoffset is not stable enough to ship. The reaping probe is the honest approximation; if you want exact WNOWAIT semantics on Darwin it likely needs the Rust side.Testing
backend/tests/test_contained_subprocess_waitid_fallback.py(5 tests) simulates the macOS platform (monkeypatch.delattr(os, 'waitid', raising=False)— on Linux CI it deletes the real attr; on macOS it is already absent) and pins: running child pollsNone, real exit codes surface (exit 3 → 3),kill()+wait()work, own-handle reaping reports the code, foreign reaping is refused.test_contained_subprocess.pystill passes (7 tests) andtest_sidecar_install.py(36) passes./v1/audio/speechpockettts requests → 200 at 27.8s (cold) / 5.9s / 5.0s, zero waitid errors; pre-fix the second request 500'd.Adds a macOS fallback for
OwnedPopenwhen CPython lacksos.waitid, usingwaitpid(WNOHANG)to preserve ownership and exit-code handling. This fixes repeated TTS failures and sidecar reaper errors on macOS while preserving Linux behavior. Review the residual PID-reuse risk during group signaling after foreign reaping.