[pull] main from python:main

Doc/library/contextlib.rst

@@ -21,9 +21,9 @@ Functions and classes provided:
 .. class:: AbstractContextManager
 
    An :term:`abstract base class` for classes that implement
-   :meth:`object.__enter__` and :meth:`object.__exit__`. A default
-   implementation for :meth:`object.__enter__` is provided which returns
-   ``self`` while :meth:`object.__exit__` is an abstract method which by default
+   :meth:`~object.__enter__` and :meth:`~object.__exit__`. A default
+   implementation for :meth:`~object.__enter__` is provided which returns
+   ``self`` while :meth:`~object.__exit__` is an abstract method which by default
    returns ``None``. See also the definition of :ref:`typecontextmanager`.
 
    .. versionadded:: 3.6
@@ -32,9 +32,9 @@ Functions and classes provided:
 .. class:: AbstractAsyncContextManager
 
    An :term:`abstract base class` for classes that implement
-   :meth:`object.__aenter__` and :meth:`object.__aexit__`. A default
-   implementation for :meth:`object.__aenter__` is provided which returns
-   ``self`` while :meth:`object.__aexit__` is an abstract method which by default
+   :meth:`~object.__aenter__` and :meth:`~object.__aexit__`. A default
+   implementation for :meth:`~object.__aenter__` is provided which returns
+   ``self`` while :meth:`~object.__aexit__` is an abstract method which by default
    returns ``None``. See also the definition of
    :ref:`async-context-managers`.
 
@@ -228,7 +228,7 @@ Functions and classes provided:
 
 .. function:: nullcontext(enter_result=None)
 
-   Return a context manager that returns *enter_result* from ``__enter__``, but
+   Return a context manager that returns *enter_result* from :meth:`~object.__enter__`, but
    otherwise does nothing. It is intended to be used as a stand-in for an
    optional context manager, for example::
 
@@ -335,7 +335,7 @@ Functions and classes provided:
    For example, the output of :func:`help` normally is sent to *sys.stdout*.
    You can capture that output in a string by redirecting the output to an
    :class:`io.StringIO` object. The replacement stream is returned from the
-   ``__enter__`` method and so is available as the target of the
+   :meth:`~object.__enter__` method and so is available as the target of the
    :keyword:`with` statement::
 
         with redirect_stdout(io.StringIO()) as f:
@@ -396,7 +396,8 @@ Functions and classes provided:
    A base class that enables a context manager to also be used as a decorator.
 
    Context managers inheriting from ``ContextDecorator`` have to implement
-   ``__enter__`` and ``__exit__`` as normal. ``__exit__`` retains its optional
+   :meth:`~object.__enter__` and :meth:`~object.__exit__` as normal.
+   ``__exit__`` retains its optional
    exception handling even when used as a decorator.
 
    ``ContextDecorator`` is used by :func:`contextmanager`, so you get this
@@ -710,9 +711,9 @@ context management protocol.
 Catching exceptions from ``__enter__`` methods
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-It is occasionally desirable to catch exceptions from an ``__enter__``
+It is occasionally desirable to catch exceptions from an :meth:`~object.__enter__`
 method implementation, *without* inadvertently catching exceptions from
-the :keyword:`with` statement body or the context manager's ``__exit__``
+the :keyword:`with` statement body or the context manager's :meth:`~object.__exit__`
 method. By using :class:`ExitStack` the steps in the context management
 protocol can be separated slightly in order to allow this::
 

Doc/using/cmdline.rst

@@ -687,6 +687,13 @@ Miscellaneous options
 
      .. versionadded:: 3.14
 
+   * :samp:`-X pathconfig_warnings={0,1}` if true (``1``) then
+     :ref:`sys-path-init` is allowed to log warnings into stderr.
+     If false (``0``) suppress these warnings. Set to true by default.
+     See also :envvar:`PYTHON_PATHCONFIG_WARNINGS`.
+
+     .. versionadded:: next
+
    * :samp:`-X tlbc={0,1}` enables (1, the default) or disables (0) thread-local
      bytecode in builds configured with :option:`--disable-gil`.  When disabled,
      this also disables the specializing interpreter.  See also
@@ -1354,6 +1361,14 @@ conflict.
 
    .. versionadded:: 3.14
 
+.. envvar:: PYTHON_PATHCONFIG_WARNINGS
+
+   If true (``1``) then :ref:`sys-path-init` is allowed to log warnings into
+   stderr. If false (``0``) suppress these warnings. Set to true by default.
+   See also :option:`-X pathconfig_warnings<-X>`.
+
+   .. versionadded:: next
+
 .. envvar:: PYTHON_JIT
 
    On builds where experimental just-in-time compilation is available, this

Lib/inspect.py

@@ -153,19 +153,19 @@
 import itertools
 import linecache
 import os
-import re
+lazy import re
 import sys
-import tokenize
+lazy import tokenize
 import token
 import types
 import functools
 import builtins
 from keyword import iskeyword
 from operator import attrgetter
 from collections import namedtuple, OrderedDict
-from weakref import ref as make_weakref
+from _weakref import ref as make_weakref
 
-# Create constants for the compiler flags in Include/code.h
+# Create constants for the compiler flags in Include/cpython/code.h
 # We try to get them from dis to avoid duplication
 mod_dict = globals()
 for k, v in dis.COMPILER_FLAG_NAMES.items():

Lib/test/pythoninfo.py

@@ -539,6 +539,7 @@ def collect_sysconfig(info_add):
         'SHELL',
         'SOABI',
         'TEST_MODULES',
+        'VAPTH',
         'abs_builddir',
         'abs_srcdir',
         'prefix',

Lib/test/support/__init__.py

@@ -1716,9 +1716,10 @@ def _platform_specific(self):
                 ))
 
             self._env = {k.upper(): os.getenv(k) for k in os.environ}
-            self._env["PYTHONHOME"] = os.path.dirname(self.real)
+            home = os.path.dirname(self.real)
             if sysconfig.is_python_build():
-                self._env["PYTHONPATH"] = STDLIB_DIR
+                home = os.path.join(home, sysconfig.get_config_var('VPATH'))
+            self._env["PYTHONHOME"] = home
     else:
         def _platform_specific(self):
             pass

Lib/test/test_builtin.py

@@ -2993,6 +2993,12 @@ def test_type_doc(self):
             A.__doc__ = doc
             self.assertEqual(A.__doc__, doc)
 
+    def test_type_frozendict(self):
+        A = type('A', (), frozendict({'x': 4, 'y': 2}))
+        self.assertEqual(A.x, 4)
+        self.assertEqual(A.y, 2)
+        self.assertEqual(A.__name__, 'A')
+
     def test_bad_args(self):
         with self.assertRaises(TypeError):
             type()

Lib/test/test_dict.py

@@ -1569,6 +1569,26 @@ def make_pairs():
                 self.assertEqual(d.get(key3_3), 44)
                 self.assertGreaterEqual(eq_count, 1)
 
+    def test_overwrite_managed_dict(self):
+        # GH-130327: Overwriting an object's managed dictionary with another object's
+        # skipped traversal in favor of inline values, causing the GC to believe that
+        # the __dict__ wasn't reachable.
+        import gc
+
+        class Shenanigans:
+            pass
+
+        to_be_deleted = Shenanigans()
+        to_be_deleted.attr = "whatever"
+        holds_reference = Shenanigans()
+        holds_reference.__dict__ = to_be_deleted.__dict__
+        holds_reference.ref = {"circular": to_be_deleted, "data": 42}
+
+        del to_be_deleted
+        gc.collect()
+        self.assertEqual(holds_reference.ref['data'], 42)
+        self.assertEqual(holds_reference.attr, "whatever")
+
     def test_unhashable_key(self):
         d = {'a': 1}
         key = [1, 2, 3]

Lib/test/test_embed.py

@@ -1491,8 +1491,12 @@ def test_init_setpythonhome(self):
         }
         self.default_program_name(config)
         env = {'TESTHOME': home, 'PYTHONPATH': paths_str}
+        # When running from source, TESTHOME will be the build directory, which
+        # isn't a valid home unless _is_python_build is set. getpath will then
+        # fail to find the standard library and show a warning, so we need to
+        # ignore stderr.
         self.check_all_configs("test_init_setpythonhome", config,
-                               api=API_COMPAT, env=env)
+                               api=API_COMPAT, env=env, ignore_stderr=True)
 
     def test_init_is_python_build_with_home(self):
         # Test _Py_path_config._is_python_build configuration (gh-91985)
@@ -1528,15 +1532,26 @@ def test_init_is_python_build_with_home(self):
             'exec_prefix': exec_prefix,
             'base_exec_prefix': exec_prefix,
             'pythonpath_env': paths_str,
-            'stdlib_dir': stdlib,
+            'stdlib_dir': stdlib,  # Only correct on _is_python_build==0!
         }
         # The code above is taken from test_init_setpythonhome()
         env = {'TESTHOME': home, 'PYTHONPATH': paths_str}
 
         env['NEGATIVE_ISPYTHONBUILD'] = '1'
         config['_is_python_build'] = 0
+        # This configuration doesn't set a valid stdlibdir/plststdlibdir because
+        # with _is_python_build=0 getpath doesn't check for the build directory
+        # landmarks in PYTHONHOME/Py_SetPythonHome.
+        # getpath correctly shows a warning, which messes up check_all_configs,
+        # so we need to ignore stderr.
         self.check_all_configs("test_init_is_python_build", config,
-                               api=API_COMPAT, env=env)
+                               api=API_COMPAT, env=env, ignore_stderr=True)
+
+        # config['stdlib_dir'] = os.path.join(home, 'Lib')
+        # FIXME: This test does not check if stdlib_dir is calculated correctly.
+        #        test_init_is_python_build runs the initialization twice,
+        #        setting stdlib_dir in _Py_path_config on the first run, which
+        #        then overrides the stdlib_dir calculation (as of GH-108730).
 
         env['NEGATIVE_ISPYTHONBUILD'] = '0'
         config['_is_python_build'] = 1
@@ -1551,8 +1566,14 @@ def test_init_is_python_build_with_home(self):
             expected_paths[0] = self.module_search_paths(prefix=prefix)[0]
             config.update(prefix=prefix, base_prefix=prefix,
                           exec_prefix=exec_prefix, base_exec_prefix=exec_prefix)
+        # This also shows the bad stdlib warning, getpath is run twice. The
+        # first time with _is_python_build=0, which results in the warning just
+        # as explained above. However, the second time a valid standard library
+        # should be found, but the stdlib_dir is cached in _Py_path_config from
+        # the first run, which ovewrites it, so it also shows the warning.
+        # Also ignore stderr.
         self.check_all_configs("test_init_is_python_build", config,
-                               api=API_COMPAT, env=env)
+                               api=API_COMPAT, env=env, ignore_stderr=True)
 
     def copy_paths_by_env(self, config):
         all_configs = self._get_expected_config()
@@ -1612,6 +1633,7 @@ def test_init_pybuilddir_win32(self):
             prefix = os.path.normpath(os.path.join(tmpdir, vpath))
             # The stdlib dir is dirname(executable) + VPATH + 'Lib'
             stdlibdir = os.path.normpath(os.path.join(tmpdir, vpath, 'Lib'))
+            os.mkdir(stdlibdir)
 
             filename = os.path.join(tmpdir, 'pybuilddir.txt')
             with open(filename, "w", encoding="utf8") as fp:

Lib/test/test_inspect/test_inspect.py

@@ -173,6 +173,15 @@ def __get__(self, instance, owner):
         return self.func.__get__(instance, owner)
 
 
+class TestImportTime(unittest.TestCase):
+
+    @cpython_only
+    def test_lazy_import(self):
+        import_helper.ensure_lazy_imports(
+            "inspect", {"re", "tokenize"}
+        )
+
+
 class TestPredicates(IsTestBase):
 
     def test_excluding_predicates(self):

Lib/test/test_os/test_os.py

@@ -2778,6 +2778,16 @@ def test_fpathconf_bad_fd(self):
         self.check(os.pathconf, "PC_NAME_MAX")
         self.check(os.fpathconf, "PC_NAME_MAX")
 
+    @unittest.skipUnless(hasattr(os, 'pathconf'), 'test needs os.pathconf()')
+    @unittest.skipIf(
+        support.linked_to_musl(),
+        'musl fpathconf ignores the file descriptor and returns a constant',
+        )
+    def test_pathconf_negative_fd_uses_fd_semantics(self):
+        with self.assertRaises(OSError) as ctx:
+            os.pathconf(-1, 1)
+        self.assertEqual(ctx.exception.errno, errno.EBADF)
+
     @unittest.skipUnless(hasattr(os, 'ftruncate'), 'test needs os.ftruncate()')
     def test_ftruncate(self):
         self.check(os.truncate, 0)

Makefile.pre.in

@@ -1004,7 +1004,7 @@ platform: $(PYTHON_FOR_BUILD_DEPS) pybuilddir.txt
 # or removed in case of failure.
 pybuilddir.txt: $(PYTHON_FOR_BUILD_DEPS)
 	@echo "none" > ./pybuilddir.txt
-	$(RUNSHARED) $(PYTHON_FOR_BUILD) -S -m sysconfig --generate-posix-vars ;\
+	$(RUNSHARED) $(PYTHON_FOR_BUILD) -S -X pathconfig_warnings=0 -m sysconfig --generate-posix-vars ;\
 	if test $$? -ne 0 ; then \
 		echo "generate-posix-vars failed" ; \
 		rm -f ./pybuilddir.txt ; \

Misc/NEWS.d/next/Core_and_Builtins/2025-02-19-21-06-30.gh-issue-130327.z3TaR8.rst

@@ -0,0 +1,2 @@
+Fix erroneous clearing of an object's :attr:`~object.__dict__` if
+overwritten at runtime.

Misc/NEWS.d/next/Core_and_Builtins/2026-02-22-19-05-03.gh-issue-145118.bU6Sic.rst

@@ -0,0 +1 @@
+:func:`type` now accepts :class:`frozendict` as an argument.

Misc/NEWS.d/next/Core_and_Builtins/2026-02-26-20-51-54.gh-issue-145273.B5QcUp.rst

@@ -0,0 +1,2 @@
+A warning is now shown during :ref:`sys-path-init` if it can't find a valid
+standard library.

Misc/NEWS.d/next/Core_and_Builtins/2026-02-26-21-07-38.gh-issue-145275.qE-3O1.rst

@@ -0,0 +1,3 @@
+Added the :option:`-X pathconfig_warnings<-X>` and
+:envvar:`PYTHON_PATHCONFIG_WARNINGS` options, allowing to disable warnings
+from :ref:`sys-path-init`.

Misc/NEWS.d/next/Core_and_Builtins/2026-03-01-13-37-31.gh-issue-145335.e36kPJ.rst

@@ -0,0 +1,2 @@
+Fix a crash in :func:`os.pathconf` when called with ``-1`` as the path
+argument.

Misc/NEWS.d/next/Library/2026-02-12-17-56-17.gh-issue-117865.jE1ema.rst

@@ -0,0 +1 @@
+Reduce the import time of :mod:`inspect` module by ~20%.

Modules/getpath.py

@@ -236,6 +236,7 @@ def search_up(prefix, *landmarks, test=isfile):
 
 real_executable_dir = None
 platstdlib_dir = None
+stdlib_zip = None
 
 # ******************************************************************************
 # CALCULATE program_name
@@ -697,12 +698,13 @@ def search_up(prefix, *landmarks, test=isfile):
             library_dir = dirname(library)
         else:
             library_dir = executable_dir
-        pythonpath.append(joinpath(library_dir, ZIP_LANDMARK))
+        stdlib_zip = joinpath(library_dir, ZIP_LANDMARK)
     elif build_prefix:
         # QUIRK: POSIX uses the default prefix when in the build directory
-        pythonpath.append(joinpath(PREFIX, ZIP_LANDMARK))
+        stdlib_zip = joinpath(PREFIX, ZIP_LANDMARK)
     else:
-        pythonpath.append(joinpath(base_prefix, ZIP_LANDMARK))
+        stdlib_zip = joinpath(base_prefix, ZIP_LANDMARK)
+    pythonpath.append(stdlib_zip)
 
     if os_name == 'nt' and use_environment and winreg:
         # QUIRK: Windows also lists paths in the registry. Paths are stored
@@ -767,6 +769,23 @@ def search_up(prefix, *landmarks, test=isfile):
     config['module_search_paths_set'] = 1
 
 
+# ******************************************************************************
+# SANITY CHECKS
+# ******************************************************************************
+
+# Warn if the standard library is missing, unless pythonpath_was_set was set, as
+# that skips parts of the stdlib directories calculation — assume the provided
+# pythonpath is correct. This is how subinterpreters initialize the path for eg.
+if not py_setpath and not pythonpath_was_set and (not stdlib_zip or not isfile(stdlib_zip)):
+    home_hint = f"The Python 'home' directory was set to {home!r}, is this correct?"
+    if not stdlib_dir or not isdir(stdlib_dir):
+        hint = home_hint if home else f'sys.prefix is set to {prefix}, is this correct?'
+        warn('WARN: Could not find the standard library directory! ' + hint)
+    elif not platstdlib_dir or not isdir(platstdlib_dir):
+        hint = home_hint if home else f'sys.exec_prefix is set to {exec_prefix}, is this correct?'
+        warn('WARN: Could not find the platform standard library directory! ' + hint)
+
+
 # ******************************************************************************
 # POSIX prefix/exec_prefix QUIRKS
 # ******************************************************************************

Modules/posixmodule.c

@@ -1280,6 +1280,8 @@ get_posix_state(PyObject *module)
  *     Contains a file descriptor if path.accept_fd was true
  *     and the caller provided a signed integer instead of any
  *     sort of string.
+ *   path.is_fd
+ *     True if path was provided as a file descriptor.
  *
  *     WARNING: if your "path" parameter is optional, and is
  *     unspecified, path_converter will never get called.
@@ -1332,6 +1334,7 @@ typedef struct {
     const wchar_t *wide;
     const char *narrow;
     int fd;
+    bool is_fd;
     int value_error;
     Py_ssize_t length;
     PyObject *object;
@@ -1341,7 +1344,7 @@ typedef struct {
 #define PATH_T_INITIALIZE(function_name, argument_name, nullable, nonstrict, \
                           make_wide, suppress_value_error, allow_fd) \
     {function_name, argument_name, nullable, nonstrict, make_wide, \
-     suppress_value_error, allow_fd, NULL, NULL, -1, 0, 0, NULL, NULL}
+     suppress_value_error, allow_fd, NULL, NULL, -1, false, 0, 0, NULL, NULL}
 #ifdef MS_WINDOWS
 #define PATH_T_INITIALIZE_P(function_name, argument_name, nullable, \
                             nonstrict, suppress_value_error, allow_fd) \
@@ -1475,6 +1478,7 @@ path_converter(PyObject *o, void *p)
         }
         path->wide = NULL;
         path->narrow = NULL;
+        path->is_fd = true;
         goto success_exit;
     }
     else {
@@ -14328,8 +14332,9 @@ os_pathconf_impl(PyObject *module, path_t *path, int name)
 
     errno = 0;
 #ifdef HAVE_FPATHCONF
-    if (path->fd != -1)
+    if (path->is_fd) {
         limit = fpathconf(path->fd, name);
+    }
     else
 #endif
         limit = pathconf(path->narrow, name);