The jitter-before-first-sleep block was duplicated verbatim in
PeriodicPoller.run() and FSPoller._sweep_loop(). Move it to
BasePoller._stagger_start() with a named _STAGGER_FRACTION constant.
This also gives a testable seam outside the pragma-no-cover
event-loop glue methods.
The previous test deleted a file mid-iteration, but is_file()
caught it before stat() ran — so the new try/except never executed.
Monkeypatch Path.stat to raise FileNotFoundError on the third call
for the victim path (after is_symlink and is_file pass), simulating
the exact TOCTOU window between is_file() and stat().
Workers parked on job_available.wait() were not woken by stop(),
causing them to sleep out the full poll_idle_interval_s before
noticing _stop. With the default 1.0s interval, stop() took ~0.8s
instead of ~0.007s.
Notify all waiters on the condition in stop() so idle workers exit
immediately. Add tests for fast job pickup via notification and
fast shutdown with idle workers.
PermissionError is a subclass of OSError, so it was caught by the
broad timeout/io handler and classified as transient. An unreadable
file would retry 5 times then DLQ — permissions don't fix themselves
without operator intervention.
Add an explicit PermissionError check before the OSError catch so
unreadable files go straight to the DLQ.
The expression `str(path.stat().st_mtime_ns) if path.exists() else None`
has a TOCTOU race: the file can be deleted between exists() and stat().
The resulting FileNotFoundError propagates up to _watch_loop's except
handler, which records a breaker failure and terminates the loop — no
more push events are processed until restart.
Replace with a try/except around stat() and return early on
FileNotFoundError. The deletion event from watchfiles will handle
cleanup.
FileNotFoundError is a subclass of OSError, so it was caught by the
broad timeout/io handler and classified as transient. A file deleted
between discovery and fetch would retry 5 times on a file that's
permanently gone, then DLQ with a confusing error message.
Add an explicit FileNotFoundError check before the OSError catch so
deleted files go straight to the DLQ.
A file deleted between os.walk() and path.stat() raises
FileNotFoundError, which propagated uncaught and failed the entire
discover() sweep. With enough failures this trips the circuit
breaker, silencing the poller.
Catch FileNotFoundError around the stat() call and skip the file.
The next sweep (or watchfiles) will emit the DELETE event.
