4.8.0

• Added experimental support for running functions in subinterpreters on Python 3.13 and later
• Added support for the copy(), copy_into(), move() and move_into() methods in anyio.Path, available in Python 3.14
• Changed TaskGroup on asyncio to always spawn tasks non-eagerly, even if using a task factory created via asyncio.create_eager_task_factory(), to preserve expected Trio-like task scheduling semantics (PR by @agronholm and @graingert)
• Configure SO_RCVBUF, SO_SNDBUF and TCP_NODELAY on the selector thread waker socket pair (this should improve the performance of wait_readable() and wait_writable() when using the ProactorEventLoop) (#836; PR by @graingert)
• Fixed AssertionError when using nest-asyncio (#840)
• Fixed return type annotation of various context managers' __exit__ method (#847; PR by @Enegg)

4.7.0

• Updated TaskGroup to work with asyncio's eager task factories (#764)
• Added the wait_readable() and wait_writable() functions which will accept an object with a .fileno() method or an integer handle, and deprecated their now obsolete versions (wait_socket_readable() and wait_socket_writable()) (PR by @davidbrochart)
• Changed EventAdapter (an Event with no bound async backend) to allow set() to work even before an async backend is bound to it (#819)
• Added support for wait_readable() and wait_writable() on ProactorEventLoop (used on asyncio + Windows by default)
• Fixed a misleading ValueError in the context of DNS failures (#815; PR by @graingert)
• Fixed the return type annotations of readinto() and readinto1() methods in the anyio.AsyncFile class (#825)
• Fixed TaskInfo.has_pending_cancellation() on asyncio returning false positives in cleanup code on Python >= 3.11 (#832; PR by @gschaffner)
• Fixed cancelled cancel scopes on asyncio calling asyncio.Task.uncancel when propagating a CancelledError on exit to a cancelled parent scope (#790; PR by @gschaffner)

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