4.6.2

• Fixed regression caused by (#807) that prevented the use of parametrized async fixtures

4.6.1

This release contains all the changes from both v4.5.1 and v4.6.0, plus:

• Fixed TaskGroup and CancelScope producing cyclic references in tracebacks when raising exceptions (#806) (PR by @graingert)

4.5.2

• Fixed regression caused by (#807) that prevented the use of parametrized async fixtures.

4.5.1

As Python 3.8 support was dropped in v4.6.0, this interim release was created to bring a regression fix to Python 3.8, and adds a few other fixes also present in v4.6.1.

• Fixed acquring a lock twice in the same task on asyncio hanging instead of raising a RuntimeError (#798)
• Fixed an async fixture's self being different than the test's self in class-based tests (#633) (PR by @agronholm and @graingert)
• Fixed TypeError with TLSStream on Windows when a certificate verification error occurs when using a truststore SSL certificate (#795)
• Corrected documentation on anyio.Path regarding the limitations imposed by the current Python version on several of its methods, and made the is_junction method unavailable on Python versions earlier than 3.12 (#794)

4.6.0

• Dropped support for Python 3.8 (as #698 cannot be resolved without cancel message support)
• Fixed 100% CPU use on asyncio while waiting for an exiting task group to finish while said task group is within a cancelled cancel scope (#695)
• Fixed cancel scopes on asyncio not propagating CancelledError on exit when the enclosing cancel scope has been effectively cancelled (#698)
• Fixed asyncio task groups not yielding control to the event loop at exit if there were no child tasks to wait on
• Fixed inconsistent task uncancellation with asyncio cancel scopes belonging to a task group when said task group has child tasks running

4.5.0

• Improved the performance of anyio.Lock and anyio.Semaphore on asyncio (even up to 50 %)
• Added the fast_acquire parameter to anyio.Lock and anyio.Semaphore to further boost performance at the expense of safety (acquire() will not yield control back if there is no contention)
• Added support for the from_uri(), full_match(), parser methods/properties in anyio.Path, newly added in Python 3.13 (#737)
• Added support for more keyword arguments for run_process() and open_process(): startupinfo, creationflags, pass_fds, user, group, extra_groups and umask (#742)
• Improved the type annotations and support for PathLike in run_process() and open_process() to allow for path-like arguments, just like subprocess.Popen
• Changed the ResourceWarning from an unclosed memory object stream to include its address for easier identification
• Changed start_blocking_portal() to always use daemonic threads, to accommodate the "loitering event loop" use case
• Bumped the minimum version of Trio to v0.26.1
• Fixed __repr__() of MemoryObjectItemReceiver, when item is not defined (#767; PR by @Danipulok)
• Fixed to_process.run_sync() failing to initialize if __main__.__file__ pointed to a file in a nonexistent directory (#696)
• Fixed AssertionError: feed_data after feed_eof on asyncio when a subprocess is closed early, before its output has been read (#490)
• Fixed TaskInfo.has_pending_cancellation() on asyncio not respecting shielded scopes (#771; PR by @gschaffner)
• Fixed SocketStream.receive() returning bytearray instead of bytes when using asyncio with ProactorEventLoop (Windows) (#776)
• Fixed quitting the debugger in a pytest test session while in an active task group failing the test instead of exiting the test session (because the exit exception arrives in an exception group)
• Fixed support for Linux abstract namespaces in UNIX sockets that was broken in v4.2 (#781; PR by @tapetersen)
• Fixed KeyboardInterrupt (ctrl+c) hanging the asyncio pytest runner

4.4.0

• Added the BlockingPortalProvider class to aid with constructing synchronous counterparts to asynchronous interfaces that would otherwise require multiple blocking portals
• Added __slots__ to AsyncResource so that child classes can use __slots__ (#733; PR by Justin Su)
• Added the TaskInfo.has_pending_cancellation() method
• Fixed erroneous RuntimeError: called 'started' twice on the same task status when cancelling a task in a TaskGroup created with the start() method before the first checkpoint is reached after calling task_status.started() (#706; PR by Dominik Schwabe)
• Fixed two bugs with TaskGroup.start() on asyncio:
  • Fixed erroneous RuntimeError: called 'started' twice on the same task status when cancelling a task in a TaskGroup created with the start() method before the first checkpoint is reached after calling task_status.started() (#706; PR by Dominik Schwabe)
  • Fixed the entire task group being cancelled if a TaskGroup.start() call gets cancelled (#685, #710)
• Fixed a race condition that caused crashes when multiple event loops of the same backend were running in separate threads and simultaneously attempted to use AnyIO for their first time (#425; PR by David Jiricek and Ganden Schaffner)
• Fixed cancellation delivery on asyncio incrementing the wrong cancel scope's cancellation counter when cascading a cancel operation to a child scope, thus failing to uncancel the host task (#716)
• Fixed erroneous TypedAttributeLookupError if a typed attribute getter raises KeyError
• Fixed the asyncio backend not respecting the PYTHONASYNCIODEBUG environment variable when setting the debug flag in anyio.run()
• Fixed SocketStream.receive() not detecting EOF on asyncio if there is also data in the read buffer (#701)
• Fixed MemoryObjectStream dropping an item if the item is delivered to a recipient that is waiting to receive an item but has a cancellation pending (#728)
• Emit a ResourceWarning for MemoryObjectReceiveStream and MemoryObjectSendStream that were garbage collected without being closed (PR by Andrey Kazantcev)
• Fixed MemoryObjectSendStream.send() not raising BrokenResourceError when the last corresponding MemoryObjectReceiveStream is closed while waiting to send a falsey item (#731; PR by Ganden Schaffner)

4.3.0

• Added support for the Python 3.12 walk_up keyword argument in anyio.Path.relative_to() (PR by Colin Taylor)

• Fixed passing total_tokens to anyio.CapacityLimiter() as a keyword argument not working on the trio backend (#515)

• Fixed Process.aclose() not performing the minimum level of necessary cleanup when cancelled. Previously:

  • Cancellation of Process.aclose() could leak an orphan process
  • Cancellation of run_process() could very briefly leak an orphan process.
  • Cancellation of Process.aclose() or run_process() on Trio could leave standard streams unclosed

  (PR by Ganden Schaffner)

• Fixed Process.stdin.aclose(), Process.stdout.aclose(), and Process.stderr.aclose() not including a checkpoint on asyncio (PR by Ganden Schaffner)

• Fixed documentation on how to provide your own typed attributes

4.2.0

• Add support for byte-based paths in connect_unix, create_unix_listeners, create_unix_datagram_socket, and create_connected_unix_datagram_socket. (PR by Lura Skye)

• Enabled the Event and CapacityLimiter classes to be instantiated outside an event loop thread

• Broadly improved/fixed the type annotations. Among other things, many functions and methods that take variadic positional arguments now make use of PEP 646 TypeVarTuple to allow the positional arguments to be validated by static type checkers. These changes affected numerous methods and functions, including:

  • anyio.run()
  • TaskGroup.start_soon()
  • anyio.from_thread.run()
  • anyio.from_thread.run_sync()
  • anyio.to_thread.run_sync()
  • anyio.to_process.run_sync()
  • BlockingPortal.call()
  • BlockingPortal.start_task_soon()
  • BlockingPortal.start_task()

  (also resolves #560)

• Fixed various type annotations of anyio.Path to match Typeshed:

  • anyio.Path.__lt__()
  • anyio.Path.__le__()
  • anyio.Path.__gt__()
  • anyio.Path.__ge__()
  • anyio.Path.__truediv__()
  • anyio.Path.__rtruediv__()
  • anyio.Path.hardlink_to()
  • anyio.Path.samefile()
  • anyio.Path.symlink_to()
  • anyio.Path.with_segments()

  (PR by Ganden Schaffner)

• Fixed adjusting the total number of tokens in a CapacityLimiter on asyncio failing to wake up tasks waiting to acquire the limiter in certain edge cases (fixed with help from Egor Blagov)

• Fixed loop_factory and use_uvloop options not being used on the asyncio backend (#643)

• Fixed cancellation propagating on asyncio from a task group to child tasks if the task hosting the task group is in a shielded cancel scope (#642)

4.1.0

• Adapted to API changes made in Trio v0.23:
  • Call trio.to_thread.run_sync() using the abandon_on_cancel keyword argument instead of cancellable
  • Removed a checkpoint when exiting a task group
  • Renamed the cancellable argument in anyio.to_thread.run_sync() to abandon_on_cancel (and deprecated the old parameter name)
  • Bumped minimum version of Trio to v0.23
• Added support for voluntary thread cancellation via anyio.from_thread.check_cancelled()
• Bumped minimum version of trio to v0.23
• Exposed the ResourceGuard class in the public API (#627)
• Fixed RuntimeError: Runner is closed when running higher-scoped async generator fixtures in some cases (#619)
• Fixed discrepancy between asyncio and trio where reraising a cancellation exception in an except* block would incorrectly bubble out of its cancel scope (#634)