3.11.1 (2026-02-03)
-------------------

* SECURITY FIX CVE-2025-14550: There was a potential DoS vector for users of
  the ``asgiref.wsgi.WsgiToAsgi`` adapter. Malicious requests, including an unreasonably
  large number of values for the same header, could lead to resource exhaustion
  when building the WSGI environment.

  To mitigate this, the algorithm is changed to be more efficient, and
  ``WsgiToAsgi`` gains a new optional ``duplicate_header_limit`` parameter,
  which defaults to 100. This specifies the number of times a single header may
  be repeated before the request is rejected as malformed.

  You may override ``duplicate_header_limit`` when configuring your application::

      application = WsgiToAsgi(wsgi_app, duplicate_header_limit=200)

  Set ``duplicate_header_limit=None`` if you wish to disable this check.

* Fixed a regression in 3.11.0 in ``sync_to_async`` when wrapping a callable
  with an attribute named ``context``. (#537)

3.11.0 (2025-11-19)
-------------------

* ``sync_to_async`` gains a ``context`` parameter, similar to those for
  ``asyncio.create_task``, ``TaskGroup`` &co, that can be used on Python 3.11+ to
  control the context used by the underlying task.

  The parent context is already propagated by default but the additional
  control is useful if multiple ``sync_to_async`` calls need to share the same
  context, e.g. when used with ``asyncio.gather()``.

3.10.0 (2025-10-05)
-------------------

* Added AsyncSingleThreadContext context manager to ensure multiple AsyncToSync
  invocations use the same thread. (#511)

3.9.2 (2025-09-23)
------------------

* Adds support for Python 3.14.

* Fixes wsgi.errors file descriptor in WsgiToAsgi adapter.

3.9.1 (2025-07-08)
------------------

* Fixed deletion of Local values affecting other contexts. (#523)

* Skip CPython specific garbage collection test on pypy. (#521)

3.9.0 (2025-07-03)
------------------

* Adds support for Python 3.13.

* Drops support for (end-of-life) Python 3.8.

* Fixes an error with conflicting kwargs between AsyncToSync and the wrapped
  function. (#471)

* Fixes Local isolation between asyncio Tasks. (#478)

* Fixes a reference cycle in Local (#508)

* Fixes a deadlock in CurrentThreadExecutor with nested async_to_sync →
  sync_to_async → async_to_sync → create_task calls. (#494)

* The ApplicationCommunicator testing utility will now return the task result
  if it's already completed on send_input and receive_nothing. You may need to
  catch (e.g.) the asyncio.exceptions.CancelledError if sending messages to
  already finished consumers in your tests. (#505)

3.8.1 (2024-03-22)
------------------

* Fixes a regression in 3.8.0 affecting nested task cancellation inside
  sync_to_async.

3.8.0 (2024-03-20)
------------------

* Adds support for Python 3.12.

* Drops support for (end-of-life) Python 3.7.

* Fixes task cancellation propagation to subtasks when using synchronous Django
  middleware.

* Allows nesting ``sync_to_async`` via ``asyncio.wait_for``.

* Corrects WSGI adapter handling of root path.

* Handles case where `"client"` is ``None`` in WsgiToAsgi adapter.

3.7.2 (2023-05-27)
------------------

* The type annotations for SyncToAsync and AsyncToSync have been changed to
  more accurately reflect the kind of callables they return.

3.7.1 (2023-05-24)
------------------

* On Python 3.10 and below, the version of the "typing_extensions" package
  is now constrained to be at least version 4 (as we depend on functionality
  in that version and above)

3.7.0 (2023-05-23)
------------------

* Contextvars are now required for the implementation of `sync` as Python 3.6
  is now no longer a supported version.

* sync_to_async and async_to_sync now pass-through

* Debug and Lifespan State extensions have resulted in a typing change for some
  request and response types. This change should be backwards-compatible.

* ``asgiref`` frames will now be hidden in Django tracebacks by default.

* Raw performance and garbage collection improvements in Local, SyncToAsync,
  and AsyncToSync.

3.6.0 (2022-12-20)
------------------

* Two new functions are added to the ``asgiref.sync`` module: ``iscoroutinefunction()``
  and ``markcoroutinefunction()``.

  Python 3.12 deprecates ``asyncio.iscoroutinefunction()`` as an alias for
  ``inspect.iscoroutinefunction()``, whilst also removing the ``_is_coroutine`` marker.
  The latter is replaced with the ``inspect.markcoroutinefunction`` decorator.

  The new ``asgiref.sync`` functions are compatibility shims for these
  functions that can be used until Python 3.12 is the minimum supported
  version.

  **Note** that these functions are considered **beta**, and as such, whilst
  not likely, are subject to change in a point release, until the final release
  of Python 3.12. They are included in ``asgiref`` now so that they can be
  adopted by Django 4.2, in preparation for support of Python 3.12.

* The ``loop`` argument to ``asgiref.timeout.timeout`` is deprecated. As per other
  ``asyncio`` based APIs, the running event loop is used by default. Note that
  ``asyncio`` provides timeout utilities from Python 3.11, and these should be
  preferred where available.

* Support for the ``ASGI_THREADS`` environment variable, used by
  ``SyncToAsync``, is removed. In general, a running event-loop is not
  available to `asgiref` at import time, and so the default thread pool
  executor cannot be configured. Protocol servers, or applications, should set
  the default executor as required when configuring the event loop at
  application startup.

3.5.2 (2022-05-16)
------------------

* Allow async-callables class instances to be passed to AsyncToSync
  without warning

* Prevent giving async-callable class instances to SyncToAsync


3.5.1 (2022-04-30)
------------------

* sync_to_async in thread-sensitive mode now works corectly when the
  outermost thread is synchronous (#214)


3.5.0 (2022-01-22)
------------------

* Python 3.6 is no longer supported, and asyncio calls have been changed to
  use only the modern versions of the APIs as a result

* Several causes of RuntimeErrors in cases where an event loop was assigned
  to a thread but not running

* Speed improvements in the Local class


3.4.1 (2021-07-01)
------------------

* Fixed an issue with the deadlock detection where it had false positives
  during exception handling.


3.4.0 (2021-06-27)
------------------

* Calling sync_to_async directly from inside itself (which causes a deadlock
  when in the default, thread-sensitive mode) now has deadlock detection.

* asyncio usage has been updated to use the new versions of get_event_loop,
  ensure_future, wait and gather, avoiding deprecation warnings in Python 3.10.
  Python 3.6 installs continue to use the old versions; this is only for 3.7+

* sync_to_async and async_to_sync now have improved type hints that pass
  through the underlying function type correctly.

* All Websocket* types are now spelled WebSocket, to match our specs and the
  official spelling. The old names will work until release 3.5.0, but will
  raise deprecation warnings.

* The typing for WebSocketScope and HTTPScope's `extensions` key has been
  fixed.


3.3.4 (2021-04-06)
------------------

* The async_to_sync type error is now a warning due the high false negative
  rate when trying to detect coroutine-returning callables in Python.


3.3.3 (2021-04-06)
------------------

* The sync conversion functions now correctly detect functools.partial and other
  wrappers around async functions on earlier Python releases.


3.3.2 (2021-04-05)
------------------

* SyncToAsync now takes an optional "executor" argument if you want to supply
  your own executor rather than using the built-in one.

* async_to_sync and sync_to_async now check their arguments are functions of
  the correct type.

* Raising CancelledError inside a SyncToAsync function no longer stops a future
  call from functioning.

* ThreadSensitive now provides context hooks/override options so it can be
  made to be sensitive in a unit smaller than threads (e.g. per request)

* Drop Python 3.5 support.

* Add type annotations.

3.3.1 (2020-11-09)
------------------

* Updated StatelessServer to use ASGI v3 single-callable applications.


3.3.0 (2020-10-09)
------------------

* sync_to_async now defaults to thread-sensitive mode being on
* async_to_sync now works inside of forked processes
* WsgiToAsgi now correctly clamps its response body when Content-Length is set


3.2.10 (2020-08-18)
-------------------

* Fixed bugs due to bad WeakRef handling introduced in 3.2.8


3.2.9 (2020-06-16)
------------------

* Fixed regression with exception handling in 3.2.8 related to the contextvars fix.


3.2.8 (2020-06-15)
------------------

* Fixed small memory leak in local.Local
* contextvars are now persisted through AsyncToSync


3.2.7 (2020-03-24)
------------------

* Bug fixed in local.Local where deleted Locals would occasionally inherit
  their storage into new Locals due to memory reuse.


3.2.6 (2020-03-23)
------------------

* local.Local now works in all threading situations, no longer requires
  periodic garbage collection, and works with libraries that monkeypatch
  threading (like gevent)


3.2.5 (2020-03-11)
------------------

* __self__ is now preserved on methods by async_to_sync


3.2.4 (2020-03-10)
------------------

* Pending tasks/async generators are now cancelled when async_to_sync exits
* Contextvars now propagate changes both ways through sync_to_async
* sync_to_async now preserves attributes on functions it wraps


3.2.3 (2019-10-23)
------------------

* Added support and testing for Python 3.8.


3.2.2 (2019-08-29)
------------------

* WsgiToAsgi maps multi-part request bodies into a single WSGI input file
* WsgiToAsgi passes the `root_path` scope as SCRIPT_NAME
* WsgiToAsgi now checks the scope type to handle `lifespan` better
* WsgiToAsgi now passes the server port as a string, like WSGI
* SyncToAsync values are now identified as coroutine functions by asyncio
* SyncToAsync now handles __self__ correctly for methods


3.2.1 (2019-08-05)
------------------

* sys.exc_info() is now propagated across thread boundaries


3.2.0 (2019-07-29)
------------------

* New "thread_sensitive" argument to SyncToAsync allows for pinning of code into
  the same thread as other thread_sensitive code.
* Test collection on Python 3.7 fixed

3.1.4 (2019-07-07)
------------------

* Fixed an incompatibility with Python 3.5 introduced in the last release.


3.1.3 (2019-07-05)
------------------

* async_timeout has been removed as a dependency, so there are now no required
  dependencies.
* The WSGI adapter now sets ``REMOTE_ADDR`` from the ASGI ``client``.


3.1.2 (2019-04-17)
------------------

* New thread_critical argument to Local to tell it to not inherit contexts
  across threads/tasks.
* Local now inherits across any number of sync_to_async to async_to_sync calls
  nested inside each other


3.1.1 (2019-04-13)
------------------

* Local now cleans up storage of old threads and tasks to prevent a memory leak.


3.1.0 (2019-04-13)
------------------

* Added ``asgiref.local`` module to provide threading.local drop-in replacement.


3.0.0 (2019-03-20)
------------------

* Updated to match new ASGI 3.0 spec
* Compatibility library added that allows adapting ASGI 2 apps into ASGI 3 apps
  losslessly


2.3.2 (2018-05-23)
------------------

* Packaging fix to allow old async_timeout dependencies (2.0 as well as 3.0)


2.3.1 (2018-05-23)
------------------

* WSGI-to-ASGI adapter now works with empty bodies in responses
* Update async-timeout dependency


2.3.0 (2018-04-11)
------------------

* ApplicationCommunicator now has a receive_nothing() test available


2.2.0 (2018-03-06)
------------------

* Cancelled tasks now correctly cascade-cancel their children

* Communicator.wait() no longer re-raises CancelledError from inner coroutines


2.1.6 (2018-02-19)
------------------

* async_to_sync now works inside of threads (but is still not allowed in threads
  that have an active event loop)


2.1.5 (2018-02-14)
------------------

* Fixed issues with async_to_sync not setting the event loop correctly

* Stop async_to_sync being called from threads with an active event loop


2.1.4 (2018-02-07)
------------------

* Values are now correctly returned from sync_to_async and async_to_sync

* ASGI_THREADS environment variable now works correctly


2.1.3 (2018-02-04)
------------------

* Add an ApplicationCommunicator.wait() method to allow you to wait for an
  application instance to exit before seeing what it did.


2.1.2 (2018-02-03)
------------------

* Allow AsyncToSync to work if called from a non-async-wrapped sync context.


2.1.1 (2018-02-02)
------------------

* Allow AsyncToSync constructor to be called inside SyncToAsync.


2.1.0 (2018-01-19)
------------------

* Add `asgiref.testing` module with ApplicationCommunicator testing helper


2.0.1 (2017-11-28)
------------------

* Bugfix release to have HTTP response content message as the correct
  "http.response.content" not the older "http.response.chunk".


2.0.0 (2017-11-28)
------------------

* Complete rewrite for new async-based ASGI mechanisms and removal of
  channel layers.


1.1.2 (2017-05-16)
-----------------

* Conformance test suite now allows for retries and tests group_send's behaviour with capacity
* valid_channel_names now has a receive parameter


1.1.1 (2017-04-02)
------------------

* Error with sending to multi-process channels with the same message fixed


1.1.0 (2017-04-01)
------------------

* Process-specific channel behaviour has been changed, and the base layer
  and conformance suites updated to match.


1.0.1 (2017-03-19)
------------------

* Improved channel and group name validation
* Test rearrangements and improvements


1.0.0 (2016-04-11)
------------------

* `receive_many` is now `receive`
* In-memory layer deepcopies messages so they cannot be mutated post-send
* Better errors for bad channel/group names