Merge branch 'main' into gh-80620

Author: jhohm

.github/workflows/build.yml

@@ -15,7 +15,13 @@ permissions:
   contents: read
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}-reusable
+  # https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#concurrency
+  # 'group' must be a key uniquely representing a PR or push event.
+  # github.workflow is the workflow name
+  # github.actor is the user invoking the workflow
+  # github.head_ref is the source branch of the PR or otherwise blank
+  # github.run_id is a unique number for the current run
+  group: ${{ github.workflow }}-${{ github.actor }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
 
 env:

Doc/c-api/typeobj.rst

@@ -79,7 +79,7 @@ Quick Reference
    | :c:member:`~PyTypeObject.tp_setattro`          | :c:type:`setattrofunc`            | __setattr__,      | X | X |   | G |
    |                                                |                                   | __delattr__       |   |   |   |   |
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
-   | :c:member:`~PyTypeObject.tp_as_buffer`         | :c:type:`PyBufferProcs` *         |                   |   |   |   | % |
+   | :c:member:`~PyTypeObject.tp_as_buffer`         | :c:type:`PyBufferProcs` *         | :ref:`sub-slots`  |   |   |   | % |
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
    | :c:member:`~PyTypeObject.tp_flags`             | unsigned long                     |                   | X | X |   | ? |
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
@@ -325,9 +325,10 @@ sub-slots
    +---------------------------------------------------------+-----------------------------------+---------------+
    |                                                                                                             |
    +---------------------------------------------------------+-----------------------------------+---------------+
-   | :c:member:`~PyBufferProcs.bf_getbuffer`                 | :c:func:`getbufferproc`           |               |
+   | :c:member:`~PyBufferProcs.bf_getbuffer`                 | :c:func:`getbufferproc`           | __buffer__    |
    +---------------------------------------------------------+-----------------------------------+---------------+
-   | :c:member:`~PyBufferProcs.bf_releasebuffer`             | :c:func:`releasebufferproc`       |               |
+   | :c:member:`~PyBufferProcs.bf_releasebuffer`             | :c:func:`releasebufferproc`       | __release_\   |
+   |                                                         |                                   | buffer\__     |
    +---------------------------------------------------------+-----------------------------------+---------------+
 
 .. _slot-typedefs-table:

Doc/howto/annotations.rst

@@ -248,4 +248,9 @@ quirks by using :func:`annotationlib.get_annotations` on Python 3.14+ or
 :func:`inspect.get_annotations` on Python 3.10+. On earlier versions of
 Python, you can avoid these bugs by accessing the annotations from the
 class's :attr:`~type.__dict__`
-(e.g., ``cls.__dict__.get('__annotations__', None)``).
+(for example, ``cls.__dict__.get('__annotations__', None)``).
+
+In some versions of Python, instances of classes may have an ``__annotations__``
+attribute. However, this is not supported functionality. If you need the
+annotations of an instance, you can use :func:`type` to access its class
+(for example, ``annotationlib.get_annotations(type(myinstance))`` on Python 3.14+).

Doc/howto/isolating-extensions.rst

@@ -215,21 +215,36 @@ multiple interpreters correctly. If this is not yet the case for your
 module, you can explicitly make your module loadable only once per
 process. For example::
 
+   // A process-wide flag
    static int loaded = 0;
 
+   // Mutex to provide thread safety (only needed for free-threaded Python)
+   static PyMutex modinit_mutex = {0};
+
    static int
    exec_module(PyObject* module)
    {
+       PyMutex_Lock(&modinit_mutex);
        if (loaded) {
+           PyMutex_Unlock(&modinit_mutex);
            PyErr_SetString(PyExc_ImportError,
                            "cannot load module more than once per process");
            return -1;
        }
        loaded = 1;
+       PyMutex_Unlock(&modinit_mutex);
        // ... rest of initialization
    }
 
 
+If your module's :c:member:`PyModuleDef.m_clear` function is able to prepare
+for future re-initialization, it should clear the ``loaded`` flag.
+In this case, your module won't support multiple instances existing
+*concurrently*, but it will, for example, support being loaded after
+Python runtime shutdown (:c:func:`Py_FinalizeEx`) and re-initialization
+(:c:func:`Py_Initialize`).
+
+
 Module State Access from Functions
 ----------------------------------
 

Doc/library/archiving.rst

@@ -5,13 +5,15 @@ Data Compression and Archiving
 ******************************
 
 The modules described in this chapter support data compression with the zlib,
-gzip, bzip2 and lzma algorithms, and the creation of ZIP- and tar-format
+gzip, bzip2, lzma, and zstd algorithms, and the creation of ZIP- and tar-format
 archives.  See also :ref:`archiving-operations` provided by the :mod:`shutil`
 module.
 
 
 .. toctree::
 
+   compression.rst
+   compression.zstd.rst
    zlib.rst
    gzip.rst
    bz2.rst

Doc/library/compression.rst

@@ -0,0 +1,18 @@
+The :mod:`!compression` package
+===============================
+
+.. versionadded:: 3.14
+
+The :mod:`!compression` package contains the canonical compression modules
+containing interfaces to several different compression algorithms. Some of
+these modules have historically been available as separate modules; those will
+continue to be available under their original names for compatibility reasons,
+and will not be removed without a deprecation cycle. The use of modules in
+:mod:`!compression` is encouraged where practical.
+
+* :mod:`!compression.bz2` -- Re-exports :mod:`bz2`
+* :mod:`!compression.gzip` -- Re-exports :mod:`gzip`
+* :mod:`!compression.lzma` -- Re-exports :mod:`lzma`
+* :mod:`!compression.zlib` -- Re-exports :mod:`zlib`
+* :mod:`compression.zstd` -- Wrapper for the Zstandard compression library
+