orca/tools/repro-watcher-crash-7547

Repro harness: watcher.node main-process crash (issue #7547)

Manual, Windows-focused harness for the @parcel/watcher native crash class (0xc0000409 fail-fast / 0xc0000005 AV in watcher.node; same family as macOS #5377 and Linux #6635). Not run in CI — it deliberately crashes processes and hammers the filesystem.

All watched/churned directories live under os.tmpdir(), never the repo.

Reproduce the bug (in-process watcher, pre-fix architecture)

node tools/repro-watcher-crash-7547/run.cjs delete-root 3 15000

Spawns child.cjs, which uses @parcel/watcher in-process the way filesystem-watcher.ts did before the fix. Scenarios (arg 1):

• delete-root — subscribe to worktree-like dirs, churn files, delete the watched root mid-churn, unsubscribe (worktree deletion during agent writes). Crashes in seconds on Windows.
• unsub-churn — rapid subscribe/unsubscribe cycles against live churn. Also crashes: the trigger is unsubscribe() racing active event delivery (CancelIo from the wrong thread leaves a pending ReadDirectoryChangesW completion pointing at a freed Subscription).
• worker-mix — worker_threads sharing the process-global native Watcher.
• del-nounsub / del-nochurn / del-1lane — minimisation variants (deletion without unsubscribe does NOT crash; unsubscribe is the trigger).
• overflow, mixed.

A native crash surfaces as the child's exit code (0xC0000409 = 3221226505, 0xC0000005 = 3221225477) and the runner stops.

Verify the fix (out-of-process watcher)

Build first so the forked entry exists, then run from the repo root:

npx electron-vite build
node tools/repro-watcher-crash-7547/fixed-child.cjs 15000

fixed-child.cjs esbuild-bundles the real src/main/ipc/parcel-watcher-process.ts client and runs the same delete-root + unsub-churn load through the forked out/main/parcel-watcher-process-entry.js. Expected output: contained watcher process crashes (counted, recovered by respawn+resubscribe, surfaced through onInterruption), a final health check that sees live events, and exit 0.

Exit codes: 0 pass · 5 watcher not functional at end · 6 in-process fallback used (isolation not exercised) · 7 watchdog · 8 premature exit.