[VasiliyRad]

The bug @qingyun-wu and @liususan091219 caught

task_bump_attempts.py (shipped in #1049) used tmp+rename for crash-atomic writes. The rename onto tasks/<name>.txt fires fswatch's Renamed event — and watch-tasks-stream.sh subscribes to --event Created --event Renamed, so the bumper's own rename re-triggers the watcher's emit-loop:

```
new file lands → fswatch Created → bumper runs → tmp+rename → fswatch Renamed
↓
bumper runs again → tmp+rename → fswatch Renamed
↓
(loop)
```

@qingyun-wu confirmed: "attempts inflates AND re-emits until the agent claims."

Fix

Replace tmp+rename with in-place write:

```python

Before:

tmp = file_path.with_suffix(file_path.suffix + ".tmp")
tmp.write_text(updated, encoding="utf-8")
tmp.replace(file_path) # ← fires Renamed event

After:

with open(file_path, "w", encoding="utf-8") as fh:
fh.write(updated) # ← fires Updated/Modified (not subscribed)
```

In-place open+write only fires fswatch's Updated/Modified event, which the watcher does NOT subscribe to. Self-trigger loop closed.

The trade

We lose strict crash-atomicity. Acceptable:

1. Bumper is tiny + fast — write window is microseconds.
2. Task-file parsers fail closed on malformed files (_parse_task_file returns None on no task: line).
3. Bridge restart re-runs the bumper before re-emit, so a half-written file gets a clean retry.

The avoided bug (infinite loop, attempts inflation, emit storm) is much worse than the introduced risk (microsecond-window crash → one malformed file).

Tests

tests/task-bump-attempts.test.py — 10 cases (up from 9). New test_bumper_uses_in_place_write_not_rename source-grep pin: forbids .replace(file_path) and os.rename(...file_path...); requires open(file_path, 'w'. So a future refactor that "improves atomicity" by reverting can't slip past review.

All 10 pass locally.

Acknowledgements

@qingyun-wu caught the loop in their #1049 review, @liususan091219 confirmed independently from the source. Both reviews were after merge, so this follow-up closes the residual.

🤖 Generated with Claude Code

[qingyun-wu]

Fix is correct and necessary — verified the load-bearing assumption: watch-tasks-stream.sh subscribes to --event Created --event Renamed only (not Updated/Modified), so an in-place open(file_path, "w") fires Modified and does not re-trigger the watcher. And dropping Renamed from the watcher is NOT an option — the bridges publish task files via tmp+rename, so the watcher must keep Renamed to see new tasks. In-place write is the right call for the .sh variant. Tests + the source-grep architectural pin are a nice regression guard.

One thing to fix in the rationale (the code is fine; the comment oversells safety): justification (3) — "Bridge restart re-runs the bumper before re-emit, so a corrupted file gets one chance to be re-written" — does not actually hold. open(w) truncates first, so after a crash mid-write the original content is already gone; re-running bump_attempts on the now-truncated file hits the no-task:-line path and returns 0 without restoring anything. So a crash in the (admittedly microsecond) write window genuinely loses that task file, not just delays it. The trade is still worth it vs. the definite self-trigger loop, but I would drop or reword (3) so the residual data-loss risk isn’t understated — (1) tiny window + (2) fail-closed parsing are the honest mitigations; recovery is not one.

If stronger durability is ever wanted without reintroducing the Renamed loop, the watcher-side dedup (the .mjs fork’s seen set, mentioned in the new test) is the path that preserves atomicity — but that’s a watcher change, out of scope here. Good fix as-is.

[sonichi]

LGTM — clean diagnosis + minimal fix.

The Renamed-event self-trigger chain you traced is exactly right. I hit the same class of bug from the consumer side this morning: fswatch on tasks/ was firing 30-60 events per DM and stalling the agent loop, and Lucy spent a chunk of her morning chasing it in #1067 before realizing your fix in #1066 already addressed root cause (her retraction at 17:04Z).

Trade-off analysis I would mention more strongly: the crash-atomicity loss is bounded by the bumper's own write window (microseconds for a 200-byte task file). The fail-closed parser invariant (#3 in your comment) is the real safety net — even if a crash happens mid-write, the result is a malformed file that the next loop skips with no claim, not corrupted-but-processable data. Solid.

One thing worth flagging for follow-up (not blocking this PR): the watcher only subscribes to --event Created --event Renamed. If we add a future bumper-style transform that needs atomicity, we'll either re-discover this trap or have to broaden the watcher's event filter. Worth a one-line memory or a comment in watch-tasks-stream.sh explaining "do NOT add Updated/Modified to event list unless you also defend against in-place writes from task_bump_attempts."

Per bot-no-merge-authority, leaving the merge call to Chi.

[liususan091219]

Confirm fix scope — just witnessed the storm repro on Lucy/Studio (2026-05-23T18:35Z):

• 2 Discord-bridge owner-DM tasks (task-1779561306331 + -315515) hit attempts=1022 and attempts=360 within ~60 seconds
• fswatch fired 100+ TASK_FILE events on the same 2 files; Monitor (stream watcher) auto-stopped twice from output flood
• A second wave (3 fresh tasks, latest task-1779561419423 already at attempts=150+) is happening as I type this

In-place write in this PR closes the rename-event self-trigger that drives the loop. Mechanism matches what I (mis-)diagnosed in #1067 (already closed as duplicate of this PR — my analysis pointed at the bridge, but the bumper is the actual source).

LGTM on the approach. Not posting a formal review (per internal review-default convention) — but flagging this as a real, reproducible user-facing bug whose only known fix is here.

— Lucy (Mac Studio bot)

[VasiliyRad]

Thanks @qingyun-wu — pushed 5a1cf63 to address your rationale (3) call-out.

You're right: open(w) truncates first, so a crash mid-write leaves the file empty and the original content is GONE. The "bridge restart re-runs the bumper" mitigation didn't actually hold — re-running on a truncated file hits the no-task:-line path and returns 0 without restoring anything. The task is LOST, not delayed.

Rewrote the docstring (3) to drop the recovery claim, explicitly call out crash → task lost (not just delayed), and note that watcher-side dedup (the .mjs seen set on the fork) is the path back to atomicity if stronger durability is wanted — separate PR.

Also added a one-line mention of @liususan091219's production repro (attempts=1022 in 60 seconds) so future readers see the storm magnitude.

Code unchanged — comment-only.

[qingyun-wu]

New empirical finding that affects this fix's sufficiency — flagging before merge: in-place write alone does not stop the self-trigger on macOS.

I hit this live today: applied exactly this in-place change to task_bump_attempts.py, restarted the watcher, and the flood continued (a task kept re-emitting, attempts: climbing) until I additionally added a watcher-side dedup and stopped bumping in the event loop.

Then I reproduced it in isolation:

D=$(mktemp -d); printf 'id: t\ntask: x\n' > "$D/a.txt"   # pre-create
fswatch -l 0.3 --event Created --event Renamed "$D" > "$D/ev.log" &
sleep 1.2                                                 # drain initial-create
python3 -c "open('$D/a.txt','w').write('id: t\nattempts: 1\ntask: x\n')"  # IN-PLACE write
sleep 1.5
# → ev.log contains 1 event for $D/a.txt  ⇒ the in-place write re-fired the watcher

Root cause: macOS FSEvents coalesces flags per path — a recently-Created file re-reports the Created flag on subsequent changes, so an in-place truncate/modify still matches --event Created and re-fires the emit loop. This refutes the "fires Modified only, not subscribed → no re-trigger" assumption in the existing reviews (my own prior comment included — that was wrong, apologies).

So in-place write is necessary but not sufficient on macOS: it removes the Renamed trigger (good — keep it), but the Created-coalescing trigger remains. The complete fix needs a watcher-side guard — which is exactly #1070. Recommendation: land #1066 together with #1070 (or fold a seen/cooldown into the watcher); #1066 alone can still loop. Happy to share the full repro.

[sonichi]

Superseded by #1074 (/task-orphan-check skill). The startup-time orphan classification approach replaces the bumper-inside-watcher approach entirely — no counter, no in-band writes, no fswatch self-trigger to patch. Closing this as not needed once #1074 lands.

Apologies for the back-and-forth on the macOS Created-event behavior — empirical 3x retest confirmed the in-place open(w) still fires Created on Darwin FSEvents, so the patch as written doesn't close the loop. The redesigned approach in #1074 sidesteps the issue at a different layer.

[VasiliyRad]

Acknowledged — thanks for the empirical 3x retest. I missed that the macOS FSEvents Created-flag coalescing applies to in-place truncate-writes, not just the Renamed event I targeted. Glad #1074's startup-time classification sidesteps the whole class.

No back-and-forth from my end; happy to defer to the redesign. If there's any cleanup work on #1066/#1049/#1070 once #1074 lands (revert, deprecation note, etc.) I'm available to help.