Greenlet

=====================

- Workaround `a CPython 3.8 bug
<https://github.com/python/cpython/issues/81308>`_ that could cause
the interpreter to crash during an early phase of shutdown with the
message "Fatal Python error: Python memory allocator called without
holding the GI." This only impacted CPython 3.8a3 through CPython
3.9a5; the fix is only applied to CPython 3.8 releases (please don't
use an early alpha release of CPython 3.9).

=====================

- Deal gracefully with greenlet switches that occur while deferred
deallocation of objects is happening using CPython's "trash can"
mechanism. Previously, if a large nested container held items that
switched greenlets during delayed deallocation, and that second
greenlet also invoked the trash can, CPython's internal state could
become corrupt. This was visible as an assertion error in debug
builds. Now, the relevant internal state is saved and restored
during greenlet switches. See also `gevent issue 1909
<https://github.com/gevent/gevent/issues/1909>`_.
- Rename the C API function ``PyGreenlet_GET_PARENT`` to
``PyGreenlet_GetParent`` for consistency. The old name remains
available as a deprecated alias.

====================

- Fix a crash on older versions of the Windows C runtime when an
unhandled C++ exception was thrown inside a greenlet by another
native extension. This is a bug in that extension, and the
interpreter will still abort, but at least it does so deliberately.
Thanks to Kirill Smelkov. See `PR 286
<https://github.com/python-greenlet/greenlet/pull/286>`_.
- Musllinux wheels for aarch64 are now built, tested, and uploaded to
PyPI. Thanks to Alexander Piskun.
- This version of greenlet is known to compile and pass tests on
CPython 3.11.0a6. Earlier 3.11 releases will not work; later
releases may or may not work. See `PR 294
<https://github.com/python-greenlet/greenlet/pull/294>`_. Special
thanks to Victor Stinner, Brandt Bucher and the CPython developers.

====================

Platforms
---------

- Add experimental, untested support for 64-bit Windows on ARM using
MSVC. See `PR 271 <https://github.com/python-greenlet/greenlet/pull/271>`_.

- Drop support for very old versions of GCC and MSVC.

- Compilation now requires a compiler that either supports C++11 or
has some other intrinsic way to create thread local variables; for
older GCC, clang and SunStudio we use ``__thread``, while for older
MSVC we use ``__declspec(thread)``.

- Wheels compatible with the musllinux specification are built,
tested, and uploaded to PyPI for x86_64. (This was retroactively
done for version 1.1.2 as well.)

- This version of greenlet is known to compile and pass tests on
CPython 3.11.0a4. Earlier or later 3.11 releases may or may not
work. See `PR 280
<https://github.com/python-greenlet/greenlet/pull/280>`_. Special
thanks to Brandt Bucher and the CPython developers.

Fixes
~~~~~

- Fix several leaks that could occur when using greenlets from
multiple threads. For example, it is no longer necessary to call
``getcurrent()`` before exiting a thread to allow its main greenlet
to be cleaned up. See `issue 252 <https://github.com/python-greenlet/greenlet/issues/251>`_.

- Fix the C API ``PyGreenlet_Throw`` to perform the same error
checking that the Python API ``greenlet.throw()`` does. Previously,
it did no error checking.

- Fix C++ exception handling on 32-bit Windows. This might have
ramifications if you embed Python in your application and also use
SEH on 32-bit windows, or if you embed Python in a C++ application.
Please contact the maintainers if you have problems in this area.

In general, C++ exception handling is expected to be better on most
platforms. This work is ongoing.

Changes
~~~~~~~

- The repr of some greenlets has changed. In particular, if the
greenlet object was running in a thread that has exited, the repr
now indicates that. *NOTE:* The repr of a greenlet is not part of
the API and should not be relied upon by production code. It is
likely to differ in other implementations such as PyPy.

- Main greenlets from threads that have exited are now marked as dead.

========================

- Add musllinux (Alpine) binary wheels.

.. important:: This preliminary support for Python 3.11 leaks memory.
Please upgrade to greenlet 2 if you're using Python 3.11.

==================

- Add support for Python 3.11. Please note that Windows binary wheels
are not available at this time.

.. important:: This preliminary support for Python 3.11 leaks memory.
Please upgrade to greenlet 2 if you're using Python 3.11.