Fix auth store file lock for Windows#455
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teknium1 merged 1 commit intoNousResearch:mainfrom Mar 10, 2026
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fcntl is not available on Windows. This adds msvcrt.locking as a fallback for cross-process advisory locking on Windows. msvcrt.locking is not reentrant within the same thread, unlike fcntl.flock. This matters because resolve_codex_runtime_credentials holds the lock and then calls _save_codex_tokens, which tries to acquire it again. Without reentrancy tracking, this deadlocks on Windows after a 15-second timeout. Uses threading.local() to track lock depth per thread, allowing nested acquisitions to pass through without re-acquiring the underlying lock. Also handles msvcrt-specific requirements: file must be opened in r+ mode (not a+), must have at least 1 byte of content, and the file pointer must be at position 0 before locking.
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Problem
_auth_store_lockinhermes_cli/auth.pyusesfcntl.flockfor cross-process locking, which doesn't exist on Windows. Without a lock backend, auth operations silently skip locking entirely.Additionally,
resolve_codex_runtime_credentialsacquires the lock and then calls_save_codex_tokens, which tries to acquire it again from the same thread.fcntl.flockhandles this fine because it's reentrant per-thread on Unix. The Windows equivalent (msvcrt.locking) is not reentrant, so this nested call deadlocks for 15 seconds and then throws aTimeoutError.Fix
msvcrt.lockingas the lock backend whenfcntlis unavailable (Windows).threading.local()so nested acquisitions from the same thread pass through without re-acquiring the underlying lock.msvcrt-specific requirements: file opened inr+mode (nota+), at least 1 byte of content, file pointer at position 0.Testing
Ran
hermes doctoron Windows 11. Before:TimeoutErrorafter 15s on Codex auth check. After: completes normally.