Add idempotency guards to patch_audit_functions() and start_blocking_io_detection() - #10
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adriaardila merged 2 commits intoJul 20, 2026
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…io_detection() Calling either twice in the same process silently double-wraps stdlib functions and/or double-registers the sys.audit hook, permanently double-counting every blocking event with no warning - e.g. when two independent conftest.py fixtures or an app factory both run setup. Mirrors the guard detect_slow_tasks() already had. Adds test coverage for all three setup functions (detect_slow_tasks() had none either), and resets the new flags in test_uvloop.py's fixture so its per-test setup stays isolated.
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Fixes #9
Summary:
detect_slow_tasks()already guards against being called twice; the other two setup functions didn't, so a second call in the same process silently double-wraps stdlib functions and/or double-registers thesys.audithook (permanent, since hooks can't be removed), quadruple-counting blocking events with no warning. See #9 for the full writeup and reproduction.Changes:
Mirrors
detect_slow_tasks()'s existing guard on both functions.Tests:
TestSetupIdempotencycovers all three setup functions (includingdetect_slow_tasks(), which had no coverage either).test_uvloop.py's reset fixture now resets the two new flags too, so its tests keep getting fresh setup per test instead of silently no-op'ing.Note
Low Risk
Small defensive change to startup setup with tests; no auth, data, or API behavior changes beyond preventing duplicate instrumentation.
Overview
patch_audit_functions()andstart_blocking_io_detection()now matchdetect_slow_tasks(): a process-wide “already configured” flag makes repeat calls a no-op with a warning, instead of double-wrapping stdlib functions or registering anothersys.audithook (which would inflate blocking-event counts).Tests:
TestSetupIdempotencyasserts second calls leave patched function identity,trace_depth, and slow-task threshold unchanged and log the expected warnings. The uvloop reset fixture documents that the two new flags are not cleared between tests so the suite does not re-patch or re-register hooks every case.Reviewed by Cursor Bugbot for commit 3af6415. Bugbot is set up for automated code reviews on this repo. Configure here.