[pull] main from python:main

Doc/library/site.rst

@@ -64,7 +64,8 @@ When running under a :ref:`virtual environment <sys-path-init-virtual-environmen
 the ``pyvenv.cfg`` file in :data:`sys.prefix` is checked for site-specific
 configurations. If the ``include-system-site-packages`` key exists and is set to
 ``true`` (case-insensitive), the system-level prefixes will be searched for
-site-packages, otherwise they won't.
+site-packages, otherwise they won't.  If the system-level prefixes are not searched then
+the user site prefixes are also implicitly not searched for site-packages.
 
 .. index::
    single: # (hash); comment

Doc/library/sys_path_init.rst

@@ -57,15 +57,19 @@ otherwise they are set to the same value as :data:`sys.base_prefix` and
 :data:`sys.base_exec_prefix`, respectively.
 This is used by :ref:`sys-path-init-virtual-environments`.
 
-Finally, the :mod:`site` module is processed and :file:`site-packages` directories
-are added to the module search path. A common way to customize the search path is
-to create :mod:`sitecustomize` or :mod:`usercustomize` modules as described in
-the :mod:`site` module documentation.
+Finally, the :mod:`site` module is processed and :file:`site-packages`
+directories are added to the module search path.  The :envvar:`PYTHONUSERBASE`
+environment variable controls where is searched for user site-packages and the
+:envvar:`PYTHONNOUSERSITE` environment variable prevents searching for user
+site-packages all together.  A common way to customize the search path is to
+create :mod:`sitecustomize` or :mod:`usercustomize` modules as described in the
+:mod:`site` module documentation.
 
 .. note::
 
-   Certain command line options may further affect path calculations.
-   See :option:`-E`, :option:`-I`, :option:`-s` and :option:`-S` for further details.
+   The command line options :option:`-E`, :option:`-P`, :option:`-I`,
+   :option:`-S` and :option:`-s` further affect path calculations, see their
+   documentation for details.
 
 .. versionchanged:: 3.14
 
@@ -96,11 +100,10 @@ Please refer to :mod:`site`'s
 
 .. note::
 
-   There are other ways how "virtual environments" could be implemented, this
-   documentation refers implementations based on the ``pyvenv.cfg`` mechanism,
-   such as :mod:`venv`. Most virtual environment implementations follow the
-   model set by :mod:`venv`, but there may be exotic implementations that
-   diverge from it.
+   There are other ways "virtual environments" could be implemented.
+   This documentation refers to implementations based on the ``pyvenv.cfg``
+   mechanism, such as :mod:`venv`, that many virtual environment implementations
+   follow.
 
 _pth files
 ----------

Doc/using/cmdline.rst

@@ -949,8 +949,9 @@ conflict.
 
 .. envvar:: PYTHONNOUSERSITE
 
-   If this is set, Python won't add the :data:`user site-packages directory
-   <site.USER_SITE>` to :data:`sys.path`.
+   This is equivalent to the :option:`-s` option.  If this is set, Python won't
+   add the :data:`user site-packages directory <site.USER_SITE>` to
+   :data:`sys.path`.
 
    .. seealso::
 
@@ -964,6 +965,9 @@ conflict.
    and :ref:`installation paths <sysconfig-user-scheme>` for
    ``python -m pip install --user``.
 
+   To disable the user site-packages, see :envvar:`PYTHONNOUSERSITE` or the :option:`-s`
+   option.
+
    .. seealso::
 
       :pep:`370` -- Per user site-packages directory

Include/cpython/ceval.h

@@ -23,6 +23,9 @@ _PyEval_RequestCodeExtraIndex(freefunc f) {
 
 PyAPI_FUNC(int) _PyEval_SliceIndex(PyObject *, Py_ssize_t *);
 PyAPI_FUNC(int) _PyEval_SliceIndexNotNone(PyObject *, Py_ssize_t *);
+PyAPI_FUNC(int) _PyEval_UnpackIndices(PyObject *, PyObject *,
+                                      Py_ssize_t,
+                                      Py_ssize_t *, Py_ssize_t *);
 
 
 // Trampoline API

Include/internal/pycore_list.h

@@ -14,6 +14,7 @@ extern "C" {
 
 PyAPI_FUNC(PyObject*) _PyList_Extend(PyListObject *, PyObject *);
 PyAPI_FUNC(PyObject) *_PyList_SliceSubscript(PyObject*, PyObject*);
+PyAPI_FUNC(PyObject *) _PyList_BinarySlice(PyObject *, PyObject *, PyObject *);
 extern void _PyList_DebugMallocStats(FILE *out);
 // _PyList_GetItemRef should be used only when the object is known as a list
 // because it doesn't raise TypeError when the object is not a list, whereas PyList_GetItemRef does.

Include/internal/pycore_tuple.h

@@ -25,6 +25,7 @@ extern PyStatus _PyTuple_InitGlobalObjects(PyInterpreterState *);
 
 PyAPI_FUNC(PyObject *)_PyTuple_FromStackRefStealOnSuccess(const union _PyStackRef *, Py_ssize_t);
 PyAPI_FUNC(PyObject *)_PyTuple_FromArraySteal(PyObject *const *, Py_ssize_t);
+PyAPI_FUNC(PyObject *) _PyTuple_BinarySlice(PyObject *, PyObject *, PyObject *);
 
 typedef struct {
     PyObject_HEAD

Include/internal/pycore_unicodeobject.h

@@ -32,6 +32,7 @@ extern PyObject* _PyUnicode_ResizeCompact(
     PyObject *unicode,
     Py_ssize_t length);
 extern PyObject* _PyUnicode_GetEmpty(void);
+PyAPI_FUNC(PyObject*) _PyUnicode_BinarySlice(PyObject *, PyObject *, PyObject *);
 
 
 /* Generic helper macro to convert characters of different types.

Lib/ctypes/util.py

@@ -85,24 +85,30 @@ def find_library(name):
         wintypes.DWORD,
     )
 
-    _psapi = ctypes.WinDLL('psapi', use_last_error=True)
-    _enum_process_modules = _psapi["EnumProcessModules"]
-    _enum_process_modules.restype = wintypes.BOOL
-    _enum_process_modules.argtypes = (
-        wintypes.HANDLE,
-        ctypes.POINTER(wintypes.HMODULE),
-        wintypes.DWORD,
-        wintypes.LPDWORD,
-    )
+    # gh-145307: We defer loading psapi.dll until _get_module_handles is called.
+    # Loading additional DLLs at startup for functionality that may never be
+    # used is wasteful.
+    _enum_process_modules = None
 
     def _get_module_filename(module: wintypes.HMODULE):
         name = (wintypes.WCHAR * 32767)() # UNICODE_STRING_MAX_CHARS
         if _k32_get_module_file_name(module, name, len(name)):
             return name.value
         return None
 
-
     def _get_module_handles():
+        global _enum_process_modules
+        if _enum_process_modules is None:
+            _psapi = ctypes.WinDLL('psapi', use_last_error=True)
+            _enum_process_modules = _psapi["EnumProcessModules"]
+            _enum_process_modules.restype = wintypes.BOOL
+            _enum_process_modules.argtypes = (
+                wintypes.HANDLE,
+                ctypes.POINTER(wintypes.HMODULE),
+                wintypes.DWORD,
+                wintypes.LPDWORD,
+            )
+
         process = _get_current_process()
         space_needed = wintypes.DWORD()
         n = 1024

Lib/glob.py

@@ -15,7 +15,7 @@
 
 def glob(pathname, *, root_dir=None, dir_fd=None, recursive=False,
         include_hidden=False):
-    """Return a list of paths matching a pathname pattern.
+    """Return a list of paths matching a `pathname` pattern.
 
     The pattern may contain simple shell-style wildcards a la
     fnmatch. Unlike fnmatch, filenames starting with a
@@ -25,6 +25,15 @@ def glob(pathname, *, root_dir=None, dir_fd=None, recursive=False,
     The order of the returned list is undefined. Sort it if you need a
     particular order.
 
+    If `root_dir` is not None, it should be a path-like object specifying the
+    root directory for searching. It has the same effect as changing the
+    current directory before calling it (without actually
+    changing it). If pathname is relative, the result will contain
+    paths relative to `root_dir`.
+
+    If `dir_fd` is not None, it should be a file descriptor referring to a
+    directory, and paths will then be relative to that directory.
+
     If `include_hidden` is true, the patterns '*', '?', '**'  will match hidden
     directories.
 
@@ -36,7 +45,7 @@ def glob(pathname, *, root_dir=None, dir_fd=None, recursive=False,
 
 def iglob(pathname, *, root_dir=None, dir_fd=None, recursive=False,
           include_hidden=False):
-    """Return an iterator which yields the paths matching a pathname pattern.
+    """Return an iterator which yields the paths matching a `pathname` pattern.
 
     The pattern may contain simple shell-style wildcards a la
     fnmatch. However, unlike fnmatch, filenames starting with a
@@ -46,7 +55,19 @@ def iglob(pathname, *, root_dir=None, dir_fd=None, recursive=False,
     The order of the returned paths is undefined. Sort them if you need a
     particular order.
 
-    If recursive is true, the pattern '**' will match any files and
+    If `root_dir` is not None, it should be a path-like object specifying
+    the root directory for searching. It has the same effect as changing
+    the current directory before calling it (without actually
+    changing it). If pathname is relative, the result will contain
+    paths relative to `root_dir`.
+
+    If `dir_fd` is not None, it should be a file descriptor referring to a
+    directory, and paths will then be relative to that directory.
+
+    If `include_hidden` is true, the patterns '*', '?', '**'  will match hidden
+    directories.
+
+    If `recursive` is true, the pattern '**' will match any files and
     zero or more directories and subdirectories.
     """
     sys.audit("glob.glob", pathname, recursive)

Lib/site.py

@@ -18,9 +18,11 @@
 it is also checked for site-packages (sys.base_prefix and
 sys.base_exec_prefix will always be the "real" prefixes of the Python
 installation). If "pyvenv.cfg" (a bootstrap configuration file) contains
-the key "include-system-site-packages" set to anything other than "false"
+the key "include-system-site-packages" is set to  "true"
 (case-insensitive), the system-level prefixes will still also be
-searched for site-packages; otherwise they won't.
+searched for site-packages; otherwise they won't.  If the system-level
+prefixes are not included then the user site prefixes are also implicitly
+not searched for site-packages.
 
 All of the resulting site-specific directories, if they exist, are
 appended to sys.path, and also inspected for path configuration

Lib/test/test_dict.py

@@ -1680,6 +1680,69 @@ def test_hash_collision_remove_add(self):
         self.assertEqual(len(d), len(items), d)
         self.assertEqual(d, dict(items))
 
+    def test_clear_reentrant_embedded(self):
+        # gh-130555: dict.clear() must be safe when values are embedded
+        # in an object and a destructor mutates the dict.
+        class MyObj: pass
+        class ClearOnDelete:
+            def __del__(self):
+                nonlocal x
+                del x
+
+        x = MyObj()
+        x.a = ClearOnDelete()
+
+        d = x.__dict__
+        d.clear()
+
+    def test_clear_reentrant_cycle(self):
+        # gh-130555: dict.clear() must be safe for embedded dicts when the
+        # object is part of a reference cycle and the last reference to the
+        # dict is via the cycle.
+        class MyObj: pass
+        obj = MyObj()
+        obj.f = obj
+        obj.attr = "attr"
+
+        d = obj.__dict__
+        del obj
+
+        d.clear()
+
+    def test_clear_reentrant_force_combined(self):
+        # gh-130555: dict.clear() must be safe when a destructor forces the
+        # dict from embedded/split to combined (setting ma_values to NULL).
+        class MyObj: pass
+        class ForceConvert:
+            def __del__(self):
+                d[1] = "trigger"
+
+        x = MyObj()
+        x.a = ForceConvert()
+        x.b = "other"
+
+        d = x.__dict__
+        d.clear()
+
+    def test_clear_reentrant_delete(self):
+        # gh-130555: dict.clear() must be safe when a destructor deletes
+        # a key from the same embedded dict.
+        class MyObj: pass
+        class DelKey:
+            def __del__(self):
+                try:
+                    del d['b']
+                except KeyError:
+                    pass
+
+        x = MyObj()
+        x.a = DelKey()
+        x.b = "value_b"
+        x.c = "value_c"
+
+        d = x.__dict__
+        d.clear()
+
 
 class CAPITest(unittest.TestCase):
 

Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -1577,6 +1577,44 @@ class EvilZoneInfo(self.klass):
 class CZoneInfoCacheTest(ZoneInfoCacheTest):
     module = c_zoneinfo
 
+    def test_inconsistent_weak_cache_get(self):
+        class Cache:
+            def get(self, key, default=None):
+                return 1337
+
+        class ZI(self.klass):
+            pass
+        # Class attribute must be set after class creation
+        # to override zoneinfo.ZoneInfo.__init_subclass__.
+        ZI._weak_cache = Cache()
+
+        with self.assertRaises(RuntimeError) as te:
+            ZI("America/Los_Angeles")
+        self.assertEqual(
+            str(te.exception),
+            "Unexpected instance of int in ZI weak cache for key 'America/Los_Angeles'"
+        )
+
+    def test_inconsistent_weak_cache_setdefault(self):
+        class Cache:
+            def get(self, key, default=None):
+                return default
+            def setdefault(self, key, value):
+                return 1337
+
+        class ZI(self.klass):
+            pass
+        # Class attribute must be set after class creation
+        # to override zoneinfo.ZoneInfo.__init_subclass__.
+        ZI._weak_cache = Cache()
+
+        with self.assertRaises(RuntimeError) as te:
+            ZI("America/Los_Angeles")
+        self.assertEqual(
+            str(te.exception),
+            "Unexpected instance of int in ZI weak cache for key 'America/Los_Angeles'"
+        )
+
 
 class ZoneInfoPickleTest(TzPathUserMixin, ZoneInfoTestBase):
     module = py_zoneinfo

Misc/NEWS.d/next/Core_and_Builtins/2026-02-08-13-14-00.gh-issue-144569.pjlJVe.rst

@@ -0,0 +1 @@
+Optimize ``BINARY_SLICE`` for list, tuple, and unicode by avoiding temporary ``slice`` object creation.

Misc/NEWS.d/next/Core_and_Builtins/2026-02-26-12-00-00.gh-issue-130555.TMSOIu.rst

@@ -0,0 +1,3 @@
+Fix use-after-free in :meth:`dict.clear` when the dictionary values are
+embedded in an object and a destructor causes re-entrant mutation of the
+dictionary.

Misc/NEWS.d/next/Library/2025-12-18-00-14-16.gh-issue-142781.gcOeYF.rst

@@ -0,0 +1,2 @@
+:mod:`zoneinfo`: fix a crash when instantiating :class:`~zoneinfo.ZoneInfo`
+objects for which the internal class-level cache is inconsistent.

Misc/NEWS.d/next/Library/2026-02-15-12-02-20.gh-issue-144835.w_oS_J.rst

@@ -0,0 +1,2 @@
+Added missing explanations for some parameters in :func:`glob.glob` and
+:func:`glob.iglob`.

Misc/NEWS.d/next/Windows/2026-02-27-10-57-20.gh-issue-145307.ueoT7j.rst

@@ -0,0 +1,2 @@
+Defers loading of the ``psapi.dll`` module until it is used by
+:func:`ctypes.util.dllist`.