Issue #12: sync module from CPython 3.10

MANIFEST.in

@@ -1,2 +1,2 @@
-include *.py *.txt *.rst *.md MANIFEST.in
-recursive-include docs *.rst *.py make.bat Makefile
+include *.py *.txt *.rst *.md *.ini MANIFEST.in
+recursive-include test docs *.rst *.py make.bat Makefile

NEWS.rst

@@ -1,33 +1,30 @@
 Release History
 ---------------
 
-21.6.0 (2021-06-TBD)
-^^^^^^^^^^^^^^^^^^^^^^^^
+21.6.0 (2021-06-27)
+^^^^^^^^^^^^^^^^^^^
 
 * Switched to calendar based versioning rather than continuing with pre-1.0
   semantic versioning (`#29 <https://github.com/jazzband/contextlib2/issues/29>`__)
 * Due to the inclusion of asynchronous features from Python 3.7+, the
   minimum supported Python version is now Python 3.6
   (`#29 <https://github.com/jazzband/contextlib2/issues/29>`__)
-* (WIP) Synchronised with the Python 3.10 version of contextlib, bringing the
-  following new features to Python 3.6+ (
-  `#12 <https://github.com/jazzband/contextlib2/issues/12>`__,
-  `#19 <https://github.com/jazzband/contextlib2/issues/19>`__,
-  `#27 <https://github.com/jazzband/contextlib2/issues/27>`__):
-
-  * ``asyncontextmanager`` (Python 3.7)
-  * ``aclosing`` (Python 3.10)
-  * ``AbstractAsyncContextManager`` (Python 3.7)
-  * ``AsyncContextDecorator`` (Python 3.10)
-  * ``AsyncExitStack`` (Python 3.7)
+* Synchronised with the Python 3.10 version of contextlib
+  (`#12 <https://github.com/jazzband/contextlib2/issues/12>`__), making the
+  following new features available on Python 3.6+:
+
+  * ``asyncontextmanager`` (added in Python 3.7, enhanced in Python 3.10)
+  * ``aclosing`` (added in Python 3.10)
+  * ``AbstractAsyncContextManager`` (added in Python 3.7)
+  * ``AsyncContextDecorator`` (added in Python 3.10)
+  * ``AsyncExitStack`` (added in Python 3.7)
   * async support in ``nullcontext`` (Python 3.10)
 
 * Updates to the default compatibility testing matrix:
 
   * Added: CPython 3.9, CPython 3.10
   * Dropped: CPython 2.7, CPython 3.5, PyPy2
 
-
 0.6.0.post1 (2019-10-10)
 ^^^^^^^^^^^^^^^^^^^^^^^^
 

README.rst

@@ -15,7 +15,7 @@
    :alt: Latest Docs
 
 contextlib2 is a backport of the `standard library's contextlib
-module <https://docs.python.org/3.5/library/contextlib.html>`_ to
+module <https://docs.python.org/3/library/contextlib.html>`_ to
 earlier Python versions.
 
 It also serves as a real world proving ground for possible future
@@ -28,7 +28,9 @@ contextlib2 has no runtime dependencies, but requires ``unittest2`` for testing
 on Python 2.x, as well as ``setuptools`` and ``wheel`` to generate universal
 wheel archives.
 
-Local testing is just a matter of running ``python test_contextlib2.py``.
+Local testing is a matter of running::
+
+    python3 -m unittest discover -t . -s test
 
 You can test against multiple versions of Python with
 `tox <https://tox.testrun.org/>`_::
@@ -38,10 +40,28 @@ You can test against multiple versions of Python with
 
 Versions currently tested in both tox and GitHub Actions are:
 
-* CPython 2.7
-* CPython 3.5
 * CPython 3.6
 * CPython 3.7
 * CPython 3.8
-* PyPy
+* CPython 3.9
+* CPython 3.10
 * PyPy3
+
+Updating to a new stdlib reference version
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+As of Python 3.10, 3 files needed to be copied from the CPython reference
+implementation to contextlib2:
+
+* ``Lib/contextlib.py`` -> ``contextlib2.py``
+* ``Lib/test/test_contextlib.py`` -> ``test/test_contextlib.py``
+* ``Lib/test/test_contextlib_async.py`` -> ``test/test_contextlib_async.py``
+
+For the 3.10 sync, the only changes needed to the test files were to import from
+``contextlib2`` rather than ``contextlib``. The test directory is laid out so
+that the test suite's imports from ``test.support`` work the same way they do in
+the main CPython test suite.
+
+The changes made to the ``contextlib2.py`` file to get it to run on the older
+versions (and to add back in the deprecated APIs that never graduated to the
+standard library version) are saved as a patch file in the ``dev`` directory.