A main-isolate Timer would freeze WITH the main isolate and tell us nothing,
so the watchdog runs in its own isolate: it fsyncs a heartbeat every ~500ms
(so the last on-disk heartbeat bounds a freeze to ~500ms) and every ~2s samples
this process's thread / handle-or-fd / child-host / RSS counts. A monotonically
climbing child or thread count is the leak signature the soak couldn't
reproduce on CI but a real freeze would show. Output is JSON-lines in
clide-watchdog.log, bounded by the same truncate-on-cap scheme as the crumb
files.
- watchdog.dart (Flutter-free, tested): ResourceSample, ResourceSampler
(forPlatform), PosixResourceSampler (/proc/self: Threads, fd count, task
children, ProcessInfo.currentRss), WatchdogFile (bounded fsynced JSON-lines),
runWatchdog (the loop, bounded by maxTicks for tests), watchdogEntry (the
sendable Isolate.spawn entry).
- watchdog_windows.dart (coverage:ignore — Win32 FFI, validated only at runtime
on Windows): one CreateToolhelp32Snapshot for thread + conhost/OpenConsole
child count, GetProcessHandleCount, ProcessInfo.currentRss. Exhaustively
defensive: any failure yields a -1 field, snapshot handle always closed, never
throws.
- main.dart: spawn the watchdog at boot (desktop only), non-fatal. Per-line
fsync means the OS reaping the isolate at exit loses nothing.
Tests: ResourceSample.toJson, Posix sampler against real /proc, WatchdogFile
(JSON shape, cap, disabled), runWatchdog (immediate baseline tick). Coverage
gate 95.08%.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
jpmschweitzerandClaude Opus 4.8
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