push, push_all and delete hold <path>.lock (flock; LockFileEx over the whole file on
Windows, as cultcache-ts store-file.ts) across the read and the replace. The staged file
is <path>.tmp-<pid>-<uuid>, fsynced before os.replace, with a directory fsync after off
Windows; a failed write removes its staged file and leaves the store.
Tests fail when the rule breaks: a write waits while a flock holder (Rust's lock) and the
TypeScript runtime's withStoreWriteLock hold the lock, three processes lose no writes,
fsync precedes replace, staged names differ, a failed replace leaves no staged file.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
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