[dependabot]

Bumps filelock from 3.29.4 to 4.2.1.

Release notes

Sourced from filelock's releases.

4.2.1

• On a singleton wrapper, close> and close> end only the holds that tasks acquired through that wrapper. A reader that arrives during close() gets the closed error instead of joining the ending hold. After synchronous code closes or force-releases the shared lock, the wrappers refuse to admit readers into the ended hold, and close() on such a wrapper returns. Closing one wrapper no longer ends a task's nested hold taken through another wrapper on the same path. #832
• ReadWriteLock locks again after a release() that an exception from a signal handler interrupted. The async read-write wrappers stop admitting readers into such a level. The async read-write locks forget a hold whose backend release failed after the backend let go, and they free the memory of each acquire that times out or is canceled. AsyncFileLock returns from release() after a few hundred acquires gave up behind a waiting one. An exception from a signal handler delivered while an AsyncFileLock call joins its queue no longer blocks every later call on that lock. #833
• Fix ReadWriteLock acting on -journal, -wal or -shm files another process puts beside its database: a write could land in another file, a reader could get in beside a writer, and an acquire could fail. SQLite now opens the database by name only in a directory no other account can write, and through a private hard link elsewhere. On Windows the directory's access control list decides. Where hard links are unavailable, keep the database in a directory other accounts cannot write, such as one under %LOCALAPPDATA%. The lock removes link directories through a checked descriptor rather than by name, reads a link directory's name only when the locking account owns it, and leaves alone a directory with other content renamed onto a link directory's name. A database whose schema takes more than a few kilobytes to load raises ValueError instead of running past the acquire timeout. #834
• Fix five bugs in opening the lock file. UnixFileLock no longer truncates a file it did not create, such as one renamed to the lock path, and no longer applies mode to it. An on_acquired hook that writes holder metadata now truncates the file itself. A lease (Linux) or an oplock (Windows) on the lock file or a soft lock's marker no longer holds acquire() past its timeout or blocking=False, and an oplock no longer holds release(); ReadWriteLock on Windows waits for its timeout and raises Timeout. On Windows, a mode without group and other bits, such as 0o600, now creates the lock file with an owner-only permission list; the ReadWriteLock database gets the same. The soft locks' writability check no longer follows a symlink swapped in at the lock path. On a filesystem without flock, a contender from another account now waits on a marker it cannot write instead of raising PermissionError. #835
• Fix SoftFileLock, MarkerSoftFileLock and SoftFileLease removing a live holder's marker in three cases: the holder and the contender run in Linux time namespaces with different boottime offsets; only one of them can read the boot id; a process other than the owner rewrote the marker. Soft markers no longer carry group or other write bits. A process name containing a carriage return or another line separator no longer makes the stale check raise ValueError. When /proc/self/ns/time exists but cannot be read, the stale check no longer compares start times and keeps the marker. #836
• The async read-write locks record their hold under a task owner, so synchronous code on the executor thread that took the hold can no longer re-enter or release it. AsyncSoftReadWriteLock gives back one level on release, so synchronous readers of a shared singleton keep theirs. SoftReadWriteLock tracks read levels per thread: release() from a thread that holds none raises RuntimeError. After its heartbeat recorded a lost hold, it refuses new acquires until that hold is released. #838
• StrictSoftFileLock creates <path>.filelock and its claims directory with the lock's mode and sets the sticky bit (a directory flag that lets only a file's owner remove it) on both. On the next acquisition it narrows a directory it owns that an earlier release created wider; it leaves a directory of another account as it is, so remove such leftovers by hand. It reaches claims through a descriptor opened without following symlinks; on Windows it holds both directories open and refuses a junction (a directory that points at another directory). Under a sticky parent such as /tmp it refuses a coordination directory of another account, as SoftReadWriteLock does for <path>.rw. One read grace now covers a whole claim scan, a failed claim cleanup no longer leaves the sentinel descriptor open, and a non-regular node at a sentinel private-record name raises SoftFileLockProtocolError. On Windows, contenders read claims without blocking their owner's unlink. #839

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Changelog

Sourced from filelock's changelog.

########### Changelog ###########

.. towncrier-draft-entries:: Unreleased

.. towncrier release notes start

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4.2.4 (2026-10-19)

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• Keep GitHub Release notes free of extra blank lines while retaining the PyPI and version comparison links. :pr:863

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4.2.3 (2026-10-19)

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• Creating a lock on a Python 3.15 interpreter without types.LazyImportType no longer triggers AttributeError at exit. :pr:860
• Handle EFTYPE when a no-follow open refuses a symlink in a soft reader/writer lock's protocol tree, so heartbeat reports lost ownership rather than a transient refresh error.

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4.2.2 (2026-10-18)

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• Fix a lock on a relative path that stayed held after a later with lock: ended, when an earlier acquire() had failed because the working directory no longer exists. That call still raises :class:FileNotFoundError, and it now leaves the lock's hold count unchanged. :pr:856

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4.2.1 (2026-10-17)

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• On a singleton wrapper, :meth:AsyncReadWriteLock.close() <filelock.AsyncReadWriteLock.close> and :meth:AsyncSoftReadWriteLock.close() <filelock.AsyncSoftReadWriteLock.close> end only the holds that tasks acquired through that wrapper. A reader that arrives during close() gets the closed error instead of joining the ending hold. After synchronous code closes or force-releases the shared lock, the wrappers refuse to admit readers into the ended hold, and close() on such a wrapper returns. Closing one wrapper no longer ends a task's nested hold taken through another wrapper on the same path. :pr:832
• :class:~filelock.ReadWriteLock locks again after a release() that an exception from a signal handler interrupted. The async read-write wrappers stop admitting readers into such a level. The async read-write locks forget a hold whose backend release failed after the backend let go, and they free the memory of each acquire that times out or is canceled. :class:~filelock.AsyncFileLock returns from release() after a few hundred acquires gave up behind a waiting one. An exception from a signal handler delivered while an :class:~filelock.AsyncFileLock call joins its queue no longer blocks every later call on that lock. :pr:833
• Fix :class:~filelock.ReadWriteLock acting on -journal, -wal or -shm files another process puts beside its database: a write could land in another file, a reader could get in beside a writer, and an acquire could fail. SQLite now opens the database by name only in a directory no other account can write, and through a private hard link elsewhere. On Windows the directory's access control list decides. Where hard links are unavailable, keep the database

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Commits

• 60331bb Release 4.2.1
• 834bf13 🧪 test(soft): skip Unix pin test on Windows
• 9d15e38 fix(soft-rw): isolate subclass singleton registries (#855)
• e1e825b 🐛 fix(open): keep lock files intact, honor deadlines and mode (#835)
• 5e3f2ec 🐛 fix(read-write): keep SQLite off shared names, bound schema (#834)
• bfa066d 🐛 fix(strict): keep claim directories private to the lock (#839)
• 977d2c3 🐛 fix(soft): wait on an empty marker instead of evicting (#846)
• 740ff66 🐛 fix(soft): break stale markers without emptying the lock path (#843)
• 86c6d5f 🐛 fix(async): honor cancellation and per-thread gates (#844)
• eeceaa8 🐛 fix(soft): keep live holders when owner identity differs (#836)
• Additional commits viewable in compare view

[davidfischer]

@dependabot rebase