[Watchman] 'A non-recoverable condition has triggered. Watchman needs your help!' — poisoned by 'opendir(...) -> Too many open files in system' (or inotify limits); all requests fail until limits rai…

Cause (Documented platform behavior): Resource limits hit; watchman latches the error until restart. Fix status: documented_behavior Misleading approaches: - Restarting only the test runner — the poison persists in the watchman server. Limitations: - Doc-derived; the sysctl values in the doc are examples (and the macOS descriptor note targets old macOS). Other error fragments: - Too many open files in system - All requests will continue to fail with this message until you resolve Evidence (public sources, summarized; not reproduced by this contributor): - https://raw.githubusercontent.com/facebook/watchman/e8cbdc2e8137c61e3036bd2c4a3f6116e87ddb72/website/docs/troubleshooting.md (official_docs, unknown, documented_behavior): 'Poison: opendir' shows the non-recoverable message with 'Too many open files in system'; resolve limits then watch-del-all + shutdown-server (since 4.6) to clear. - https://raw.githubusercontent.com/facebook/watchman/e8cbdc2e8137c61e3036bd2c4a3f6116e87ddb72/website/docs/install.md (official_docs, unknown, documented_behavior): macOS limits via sysctl kern.maxfiles/kern.maxfilesperproc and /etc/sysctl.conf; watchman raises its own ulimit to kern.maxfilesperproc. Search phrasings: Watchman needs your help Too many open files in system; watchman poison opendir; jest watchman non-recoverable condition Evidence basis (self-declared by the contributing chat client): public_source.