python
diff --git a/‎Doc/c-api/init_config.rst‎
Lines changed: 28 additions & 13 deletions b/‎Doc/c-api/init_config.rst‎
Lines changed: 28 additions & 13 deletions
diff --git a/‎Include/cpython/fileutils.h‎
Lines changed: 0 additions & 2 deletions b/‎Include/cpython/fileutils.h‎
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diff --git a/‎Include/cpython/initconfig.h‎
Lines changed: 3 additions & 0 deletions b/‎Include/cpython/initconfig.h‎
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diff --git a/‎Include/internal/pycore_fileutils.h‎
Lines changed: 3 additions & 2 deletions b/‎Include/internal/pycore_fileutils.h‎
Lines changed: 3 additions & 2 deletions
diff --git a/‎Include/internal/pycore_initconfig.h‎
Lines changed: 3 additions & 1 deletion b/‎Include/internal/pycore_initconfig.h‎
Lines changed: 3 additions & 1 deletion
diff --git a/‎Include/internal/pycore_pathconfig.h‎
Lines changed: 3 additions & 53 deletions b/‎Include/internal/pycore_pathconfig.h‎
Lines changed: 3 additions & 53 deletions
diff --git a/‎Lib/ntpath.py‎
Lines changed: 63 additions & 49 deletions b/‎Lib/ntpath.py‎
Lines changed: 63 additions & 49 deletions
@@ -479,6 +479,9 @@ PyConfig
 
       Fields which are already initialized are left unchanged.
 
+      Fields for :ref:`path configuration <init-path-config>` are no longer
+      calculated or modified when calling this function, as of Python 3.11.
+
       The :c:func:`PyConfig_Read` function only parses
       :c:member:`PyConfig.argv` arguments once: :c:member:`PyConfig.parse_argv`
       is set to ``2`` after arguments are parsed. Since Python arguments are
@@ -493,6 +496,12 @@ PyConfig
          parsed, and arguments are only parsed if
          :c:member:`PyConfig.parse_argv` equals ``1``.
 
+      .. versionchanged:: 3.11
+         :c:func:`PyConfig_Read` no longer calculates all paths, and so fields
+         listed under :ref:`Python Path Configuration <init-path-config>` may
+         no longer be updated until :c:func:`Py_InitializeFromConfig` is
+         called.
+
    .. c:function:: void PyConfig_Clear(PyConfig *config)
 
       Release configuration memory.
@@ -845,12 +854,19 @@ PyConfig
 
       Default: value of the ``PLATLIBDIR`` macro which is set by the
       :option:`configure --with-platlibdir option <--with-platlibdir>`
-      (default: ``"lib"``).
+      (default: ``"lib"``, or ``"DLLs"`` on Windows).
 
       Part of the :ref:`Python Path Configuration <init-path-config>` input.
 
       .. versionadded:: 3.9
 
+      .. versionchanged:: 3.11
+         This macro is now used on Windows to locate the standard
+         library extension modules, typically under ``DLLs``. However,
+         for compatibility, note that this value is ignored for any
+         non-standard layouts, including in-tree builds and virtual
+         environments.
+
    .. c:member:: wchar_t* pythonpath_env
 
       Module search paths (:data:`sys.path`) as a string separated by ``DELIM``
@@ -867,9 +883,9 @@ PyConfig
 
       Module search paths: :data:`sys.path`.
 
-      If :c:member:`~PyConfig.module_search_paths_set` is equal to 0, the
-      function calculating the :ref:`Python Path Configuration <init-path-config>`
-      overrides the :c:member:`~PyConfig.module_search_paths` and sets
+      If :c:member:`~PyConfig.module_search_paths_set` is equal to 0,
+      :c:func:`Py_InitializeFromConfig` will replace
+      :c:member:`~PyConfig.module_search_paths` and sets
       :c:member:`~PyConfig.module_search_paths_set` to ``1``.
 
       Default: empty list (``module_search_paths``) and ``0``
@@ -941,16 +957,16 @@ PyConfig
 
    .. c:member:: int pathconfig_warnings
 
-      On Unix, if non-zero, calculating the :ref:`Python Path Configuration
-      <init-path-config>` can log warnings into ``stderr``. If equals to 0,
-      suppress these warnings.
-
-      It has no effect on Windows.
+      If non-zero, calculation of path configuration is allowed to log
+      warnings into ``stderr``. If equals to 0, suppress these warnings.
 
       Default: ``1`` in Python mode, ``0`` in isolated mode.
 
       Part of the :ref:`Python Path Configuration <init-path-config>` input.
 
+      .. versionchanged:: 3.11
+         Now also applies on Windows.
+
    .. c:member:: wchar_t* prefix
 
       The site-specific directory prefix where the platform independent Python
@@ -1302,10 +1318,9 @@ variables, command line arguments (:c:member:`PyConfig.argv` is not parsed)
 and user site directory. The C standard streams (ex: ``stdout``) and the
 LC_CTYPE locale are left unchanged. Signal handlers are not installed.
 
-Configuration files are still used with this configuration. Set the
-:ref:`Python Path Configuration <init-path-config>` ("output fields") to ignore these
-configuration files and avoid the function computing the default path
-configuration.
+Configuration files are still used with this configuration to determine
+paths that are unspecified. Ensure :c:member:`PyConfig.home` is specified
+to avoid computing the default path configuration.
 
 
 .. _init-python-config:
 
@@ -135,9 +135,7 @@ PyAPI_FUNC(wchar_t*) _Py_wrealpath(
     size_t resolved_path_len);
 #endif
 
-#ifndef MS_WINDOWS
 PyAPI_FUNC(int) _Py_isabs(const wchar_t *path);
-#endif
 
 PyAPI_FUNC(int) _Py_abspath(const wchar_t *path, wchar_t **abspath_p);
 
 
@@ -210,6 +210,9 @@ typedef struct PyConfig {
     // If non-zero, disallow threads, subprocesses, and fork.
     // Default: 0.
     int _isolated_interpreter;
+
+    // If non-zero, we believe we're running from a source tree.
+    int _development_env;
 } PyConfig;
 
 PyAPI_FUNC(void) PyConfig_InitPythonConfig(PyConfig *config);
 
@@ -74,14 +74,15 @@ extern int _Py_EncodeNonUnicodeWchar_InPlace(
     Py_ssize_t size);
 #endif
 
+extern PyAPI_FUNC(int) _Py_isabs(const wchar_t *path);
+extern PyAPI_FUNC(int) _Py_abspath(const wchar_t *path, wchar_t **abspath_p);
 extern wchar_t * _Py_join_relfile(const wchar_t *dirname,
                                   const wchar_t *relfile);
 extern int _Py_add_relfile(wchar_t *dirname,
                            const wchar_t *relfile,
                            size_t bufsize);
 extern size_t _Py_find_basename(const wchar_t *filename);
-PyAPI_FUNC(int) _Py_normalize_path(const wchar_t *path,
-                                   wchar_t *buf, const size_t buf_len);
+PyAPI_FUNC(wchar_t *) _Py_normpath(wchar_t *path, Py_ssize_t size);
 
 
 // Macros to protect CRT calls against instant termination when passed an
 
@@ -152,7 +152,7 @@ PyAPI_FUNC(void) _PyConfig_InitCompatConfig(PyConfig *config);
 extern PyStatus _PyConfig_Copy(
     PyConfig *config,
     const PyConfig *config2);
-extern PyStatus _PyConfig_InitPathConfig(
+PyAPI_FUNC(PyStatus) _PyConfig_InitPathConfig(
     PyConfig *config,
     int compute_path_config);
 extern PyStatus _PyConfig_InitImportConfig(PyConfig *config);
@@ -166,6 +166,8 @@ extern PyStatus _PyConfig_SetPyArgv(
 PyAPI_FUNC(PyObject*) _PyConfig_AsDict(const PyConfig *config);
 PyAPI_FUNC(int) _PyConfig_FromDict(PyConfig *config, PyObject *dict);
 
+extern void _Py_DumpPathConfig(PyThreadState *tstate);
+
 
 /* --- Function used for testing ---------------------------------- */
 
 
@@ -8,65 +8,15 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
-typedef struct _PyPathConfig {
-    /* Full path to the Python program */
-    wchar_t *program_full_path;
-    wchar_t *prefix;
-    wchar_t *exec_prefix;
-    wchar_t *stdlib_dir;
-    /* Set by Py_SetPath(), or computed by _PyConfig_InitPathConfig() */
-    wchar_t *module_search_path;
-    /* Python program name */
-    wchar_t *program_name;
-    /* Set by Py_SetPythonHome() or PYTHONHOME environment variable */
-    wchar_t *home;
-#ifdef MS_WINDOWS
-    /* isolated and site_import are used to set Py_IsolatedFlag and
-       Py_NoSiteFlag flags on Windows in read_pth_file(). These fields
-       are ignored when their value are equal to -1 (unset). */
-    int isolated;
-    int site_import;
-    /* Set when a venv is detected */
-    wchar_t *base_executable;
-#endif
-} _PyPathConfig;
-
-#ifdef MS_WINDOWS
-#  define _PyPathConfig_INIT \
-      {.module_search_path = NULL, \
-       .isolated = -1, \
-       .site_import = -1}
-#else
-#  define _PyPathConfig_INIT \
-      {.module_search_path = NULL}
-#endif
-/* Note: _PyPathConfig_INIT sets other fields to 0/NULL */
-
-PyAPI_DATA(_PyPathConfig) _Py_path_config;
-#ifdef MS_WINDOWS
-PyAPI_DATA(wchar_t*) _Py_dll_path;
-#endif
-
 extern void _PyPathConfig_ClearGlobal(void);
+extern PyStatus _PyPathConfig_ReadGlobal(PyConfig *config);
+extern PyStatus _PyPathConfig_UpdateGlobal(const PyConfig *config);
+extern const wchar_t * _PyPathConfig_GetGlobalModuleSearchPath(void);
 
-extern PyStatus _PyPathConfig_Calculate(
-    _PyPathConfig *pathconfig,
-    const PyConfig *config);
 extern int _PyPathConfig_ComputeSysPath0(
     const PyWideStringList *argv,
     PyObject **path0);
-extern PyStatus _Py_FindEnvConfigValue(
-    FILE *env_file,
-    const wchar_t *key,
-    wchar_t **value_p);
-
-#ifdef MS_WINDOWS
-extern wchar_t* _Py_GetDLLPath(void);
-#endif
 
-extern PyStatus _PyConfig_WritePathConfig(const PyConfig *config);
-extern void _Py_DumpPathConfig(PyThreadState *tstate);
-extern PyObject* _PyPathConfig_AsDict(void);
 
 #ifdef __cplusplus
 }
 
@@ -70,7 +70,7 @@ def isabs(s):
         if s.replace('/', '\\').startswith('\\\\?\\'):
             return True
     s = splitdrive(s)[1]
-    return len(s) > 0 and s[0] in _get_bothseps(s)
+    return len(s) > 0 and s[0] and s[0] in _get_bothseps(s)
 
 
 # Join two (or more) paths.
@@ -268,11 +268,13 @@ def ismount(path):
     root, rest = splitdrive(path)
     if root and root[0] in seps:
         return (not rest) or (rest in seps)
-    if rest in seps:
+    if rest and rest in seps:
         return True
 
     if _getvolumepathname:
-        return path.rstrip(seps) == _getvolumepathname(path).rstrip(seps)
+        x = path.rstrip(seps)
+        y =_getvolumepathname(path).rstrip(seps)
+        return x.casefold() == y.casefold()
     else:
         return False
 
@@ -459,56 +461,68 @@ def expandvars(path):
 # Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A\B.
 # Previously, this function also truncated pathnames to 8+3 format,
 # but as this module is called "ntpath", that's obviously wrong!
+try:
+    from nt import _path_normpath
 
-def normpath(path):
-    """Normalize path, eliminating double slashes, etc."""
-    path = os.fspath(path)
-    if isinstance(path, bytes):
-        sep = b'\\'
-        altsep = b'/'
-        curdir = b'.'
-        pardir = b'..'
-        special_prefixes = (b'\\\\.\\', b'\\\\?\\')
-    else:
-        sep = '\\'
-        altsep = '/'
-        curdir = '.'
-        pardir = '..'
-        special_prefixes = ('\\\\.\\', '\\\\?\\')
-    if path.startswith(special_prefixes):
-        # in the case of paths with these prefixes:
-        # \\.\ -> device names
-        # \\?\ -> literal paths
-        # do not do any normalization, but return the path
-        # unchanged apart from the call to os.fspath()
-        return path
-    path = path.replace(altsep, sep)
-    prefix, path = splitdrive(path)
-
-    # collapse initial backslashes
-    if path.startswith(sep):
-        prefix += sep
-        path = path.lstrip(sep)
-
-    comps = path.split(sep)
-    i = 0
-    while i < len(comps):
-        if not comps[i] or comps[i] == curdir:
-            del comps[i]
-        elif comps[i] == pardir:
-            if i > 0 and comps[i-1] != pardir:
-                del comps[i-1:i+1]
-                i -= 1
-            elif i == 0 and prefix.endswith(sep):
+except ImportError:
+    def normpath(path):
+        """Normalize path, eliminating double slashes, etc."""
+        path = os.fspath(path)
+        if isinstance(path, bytes):
+            sep = b'\\'
+            altsep = b'/'
+            curdir = b'.'
+            pardir = b'..'
+            special_prefixes = (b'\\\\.\\', b'\\\\?\\')
+        else:
+            sep = '\\'
+            altsep = '/'
+            curdir = '.'
+            pardir = '..'
+            special_prefixes = ('\\\\.\\', '\\\\?\\')
+        if path.startswith(special_prefixes):
+            # in the case of paths with these prefixes:
+            # \\.\ -> device names
+            # \\?\ -> literal paths
+            # do not do any normalization, but return the path
+            # unchanged apart from the call to os.fspath()
+            return path
+        path = path.replace(altsep, sep)
+        prefix, path = splitdrive(path)
+
+        # collapse initial backslashes
+        if path.startswith(sep):
+            prefix += sep
+            path = path.lstrip(sep)
+
+        comps = path.split(sep)
+        i = 0
+        while i < len(comps):
+            if not comps[i] or comps[i] == curdir:
                 del comps[i]
+            elif comps[i] == pardir:
+                if i > 0 and comps[i-1] != pardir:
+                    del comps[i-1:i+1]
+                    i -= 1
+                elif i == 0 and prefix.endswith(sep):
+                    del comps[i]
+                else:
+                    i += 1
             else:
                 i += 1
-        else:
-            i += 1
-    # If the path is now empty, substitute '.'
-    if not prefix and not comps:
-        comps.append(curdir)
-    return prefix + sep.join(comps)
+        # If the path is now empty, substitute '.'
+        if not prefix and not comps:
+            comps.append(curdir)
+        return prefix + sep.join(comps)
+
+else:
+    def normpath(path):
+        """Normalize path, eliminating double slashes, etc."""
+        path = os.fspath(path)
+        if isinstance(path, bytes):
+            return os.fsencode(_path_normpath(os.fsdecode(path))) or b"."
+        return _path_normpath(path) or "."
+
 
 def _abspath_fallback(path):
     """Return the absolute version of a path as a fallback function in case