Import CPython 3.15.0+dev stable branch (2026-10-10)

Summary:
Imported python/cpython `3.15.0+dev` from upstream rev [`d59ff39`](https://www.github.com/python/cpython/commit/d59ff393d718cd0ba209b23004178c21ce85a0a0) (committed 2026-10-10 21:32:17+00:00).

# Commit Info

- Base: (`3.15.0+dev`) - [`b57aea1`](https://www.github.com/python/cpython/commit/b57aea1261e419361c82d3fde02bc919be5e979f) (commit date: 2026-10-09 13:58:09+00:00)
- Imported: (`3.15.0+dev`) - [`d59ff39`](https://www.github.com/python/cpython/commit/d59ff393d718cd0ba209b23004178c21ce85a0a0) (commit date: 2026-10-10 21:32:17+00:00)

# Noteworthy file changes

- Native files (2 added):
  ```
  + Modules/_testlimitedcapi/slice.c
  + Modules/_testlimitedcapi/type.c
  ```
- Test files (5 added, 1 removed)
- Low-signal files (124 added) (NEWS.d, docs, .github)

Complete list of added/removed files: https://www.internalfb.com/intern/everpaste/?color=0&handle=GNUTMjKwSXewS2cGALFEg3JXMQ4Hbr0LAAAz

Reviewed By: alexmalyshev

Differential Revision: D124612611

fbshipit-source-id: adcdbbadcfbcd566974d1949ea06dcae1024fa3a

Author: itamaro

.github/CODEOWNERS

@@ -624,6 +624,12 @@ Lib/test/test_unittest/testmock/ @cjw296
 # Weakref
 **/*weakref*                  @kumaraditya303
 
+# Zlib
+Doc/library/zlib.rst          @StanFromIreland
+Lib/compression/zlib.py       @StanFromIreland
+Lib/test/test_zlib.py         @StanFromIreland
+Modules/_zlibmodule.c         @StanFromIreland
+
 # Zipfile.Path
 Lib/test/test_zipfile/_path/  @jaraco
 Lib/zipfile/_path/            @jaraco

.github/workflows/mypy.yml

@@ -69,7 +69,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@bec219d24cd3e171d82865faccec33120bb574f4 # v10.1.0
+      - uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
         with:
           python-version: "3.15"
           activate-environment: true

.github/workflows/reusable-cifuzz.yml

@@ -43,7 +43,7 @@ jobs:
           path: ./out/artifacts
       - name: Upload SARIF
         if: always() && steps.build.outcome == 'success'
-        uses: github/codeql-action/upload-sarif@b96794f015dfd88f77b49b1c93e0fa7110f94c63 # v4.38.0
+        uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
         with:
           sarif_file: cifuzz-sarif/results.sarif
           checkout_path: cifuzz-sarif

Doc/builtins/functions.rst

@@ -344,8 +344,14 @@ are always available.  They are listed here in alphabetical order.
    It is needed to unambiguous :ref:`filter <warning-filter>` syntax warnings
    by module name.
 
-   This function raises :exc:`SyntaxError` or :exc:`ValueError` if the compiled
-   source is invalid.
+   This function raises :exc:`SyntaxError` if the compiled source is invalid,
+   including a *source* containing a null character or that cannot be decoded;
+   :exc:`ValueError` if *mode* or *flags* is invalid,
+   or if a string *source* contains surrogate characters;
+   :exc:`MemoryError` or :exc:`RecursionError` if *source* is too complex
+   to parse or compile,
+   for example an expression with many thousands of nested operators;
+   and :exc:`OverflowError` if *source* is too large.
 
    If you want to parse Python code into its AST representation, see
    :func:`ast.parse`.
@@ -377,11 +383,15 @@ are always available.  They are listed here in alphabetical order.
       Previously, :exc:`TypeError` was raised when null bytes were encountered
       in *source*.
 
-   .. versionadded:: 3.8
+   .. versionchanged:: 3.8
       ``ast.PyCF_ALLOW_TOP_LEVEL_AWAIT`` can now be passed in flags to enable
       support for top-level ``await``, ``async for``, and ``async with``.
 
-   .. versionadded:: 3.15
+   .. versionchanged:: 3.12
+      :exc:`SyntaxError` is raised instead of :exc:`ValueError` when null bytes
+      are encountered in *source*.
+
+   .. versionchanged:: 3.15
       Added the *module* parameter.
 
 

Doc/c-api/bytes.rst

@@ -458,3 +458,112 @@ Low-level API
            return NULL;
        }
        return (char*)PyBytesWriter_GetData(writer) + pos;
+
+
+Example creating the string ``b'abc'``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Example creating the bytes string ``b"abc"``, with a fixed size of 3 bytes::
+
+    PyObject* create_abc(void)
+    {
+        PyBytesWriter *writer = PyBytesWriter_Create(3);
+        if (writer == NULL) {
+            return NULL;
+        }
+
+        char *str = PyBytesWriter_GetData(writer);
+        memcpy(str, "abc", 3);
+        return PyBytesWriter_Finish(writer);
+    }
+
+Variant using a pointer to compute the final size::
+
+    PyObject* create_abc_ptr(void)
+    {
+        PyBytesWriter *writer = PyBytesWriter_Create(3);
+        if (writer == NULL) {
+            return NULL;
+        }
+
+        char *str = PyBytesWriter_GetData(writer);
+        memcpy(str, "abc", 3);
+        str += 1;
+        return PyBytesWriter_FinishWithPointer(writer, str);
+    }
+
+
+Update ``PyBytes_FromStringAndSize()`` code
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Example of code using the soft deprecated
+``PyBytes_FromStringAndSize(NULL, size)`` API::
+
+    int copy_bytes(char *dest, const char *src, Py_ssize_t num_bytes)
+    {
+        ...
+    }
+
+    PyObject* create_string(const char *start, Py_ssize_t num_bytes)
+    {
+        PyObject *result = PyBytes_FromStringAndSize(NULL, num_bytes);
+        if (result == NULL) {
+            return NULL;
+        }
+        if (copy_bytes(PyBytes_AS_STRING(result), start, num_bytes) < 0) {
+            Py_CLEAR(result);
+        }
+        return result;
+    }
+
+It can now be updated to::
+
+    PyObject* create_string(const char *start, Py_ssize_t num_bytes)
+    {
+        PyBytesWriter *writer = PyBytesWriter_Create(num_bytes);
+        if (writer == NULL) {
+            return NULL;
+        }
+        if (copy_bytes(PyBytesWriter_GetData(writer), start, num_bytes) < 0) {
+            PyBytesWriter_Discard(writer);
+            return NULL;
+        }
+        return PyBytesWriter_Finish(writer);
+    }
+
+
+Update ``_PyBytes_Resize()`` code
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Example of code using the soft deprecated ``_PyBytes_Resize()`` API::
+
+    void create_string(Py_ssize_t size)
+    {
+        PyObject *bytes = PyBytes_FromStringAndSize(NULL, size);
+        if (bytes == NULL) {
+            return NULL;
+        }
+        char *str = PyBytes_AS_STRING(bytes);
+
+        // ... write data into str ...
+
+        if (_PyBytes_Resize(&bytes, (str - PyBytes_AS_STRING(bytes)))) {
+            return NULL;
+        }
+        return bytes;
+    }
+
+It can now be updated to::
+
+    void create_string(Py_ssize_t size)
+    {
+        PyBytesWriter *writer = PyBytesWriter_Create(size);
+        if (writer == NULL) {
+            return NULL;
+        }
+        char *str = PyBytesWriter_GetData(writer);
+
+        // ... write data into str ...
+
+        return PyBytesWriter_FinishWithPointer(writer, str);
+    }

Doc/c-api/slice.rst

@@ -53,6 +53,7 @@ Slice Objects
    length *length*, and store the length of the slice in *slicelength*.  Out
    of bounds indices are clipped in a manner consistent with the handling of
    normal slices.
+   *length* must not be negative.
 
    Return ``0`` on success and ``-1`` on error with an exception set.
 
@@ -108,6 +109,10 @@ Slice Objects
    Out of bounds indices are clipped in a manner consistent with the handling
    of normal slices.
 
+   *length* must not be negative.
+   *step* must not be zero and must not be less than ``-PY_SSIZE_T_MAX``,
+   as guaranteed by :c:func:`PySlice_Unpack`.
+
    Return the length of the slice.  Always successful.  Doesn't call Python
    code.
 

Doc/library/code.rst

@@ -92,7 +92,7 @@ Interactive Interpreter Objects
    *symbol* is ``'single'``.  One of several things can happen:
 
    * The input is incorrect; :func:`compile_command` raised an exception
-     (:exc:`SyntaxError` or :exc:`OverflowError`).  A syntax traceback will be
+     (usually :exc:`SyntaxError`).  A syntax traceback will be
      printed by calling the :meth:`showsyntaxerror` method.  :meth:`runsource`
      returns ``False``.
 

Doc/library/ctypes.rst

@@ -1713,6 +1713,10 @@ These prefabricated library loaders are available:
       :c:expr:`int`, which is of course not always the truth, so you have to assign
       the correct :attr:`!restype` attribute to use these functions.
 
+      .. note::
+
+         If the Python interpreter is statically linked, this may be ``None``.
+
 .. audit-event:: ctypes.dlopen name ctypes.LibraryLoader
 
    Loading a library through any of these objects raises an

Doc/library/imaplib.rst

@@ -698,6 +698,20 @@ An :class:`IMAP4` instance has the following methods:
 
 The following attributes are defined on instances of :class:`IMAP4`:
 
+.. attribute:: IMAP4.capabilities
+
+   A tuple of the capabilities advertised by the server, in upper case.
+
+   It is set when the connection is established,
+   and refreshed after a successful :meth:`~IMAP4.login`,
+   :meth:`~IMAP4.authenticate` or :meth:`~IMAP4.starttls`,
+   because the server can advertise different capabilities
+   in different connection states.
+
+   .. versionchanged:: 3.14.7
+      Refreshed after :meth:`~IMAP4.login` and :meth:`~IMAP4.authenticate`.
+
+
 .. attribute:: IMAP4.PROTOCOL_VERSION
 
    The most recent supported protocol in the ``CAPABILITY`` response from the

Doc/library/inspect.rst

@@ -485,6 +485,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
       Functions wrapped in :func:`functools.partial` now return ``True`` if the
       wrapped function is a Python generator function.
 
+   .. versionchanged:: 3.10.6
+      :term:`Duck-typed <duck-typing>` function-like objects now return
+      ``True`` if their code object has the :data:`CO_GENERATOR` flag.
+
    .. versionchanged:: 3.13
       Functions wrapped in :func:`functools.partialmethod` now return ``True``
       if the wrapped function is a Python generator function.
@@ -507,6 +511,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
       Functions wrapped in :func:`functools.partial` now return ``True`` if the
       wrapped function is a :term:`coroutine function`.
 
+   .. versionchanged:: 3.10.6
+      :term:`Duck-typed <duck-typing>` function-like objects now return
+      ``True`` if their code object has the :data:`CO_COROUTINE` flag.
+
    .. versionchanged:: 3.12
       Sync functions marked with :func:`markcoroutinefunction` now return
       ``True``.
@@ -581,6 +589,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
       Functions wrapped in :func:`functools.partial` now return ``True`` if the
       wrapped function is an :term:`asynchronous generator` function.
 
+   .. versionchanged:: 3.10.6
+      :term:`Duck-typed <duck-typing>` function-like objects now return
+      ``True`` if their code object has the :data:`CO_ASYNC_GENERATOR` flag.
+
    .. versionchanged:: 3.13
       Functions wrapped in :func:`functools.partialmethod` now return ``True``
       if the wrapped function is a :term:`asynchronous generator` function.