[pull] main from python:main

Doc/c-api/function.rst

@@ -175,6 +175,9 @@ There are a few functions specific to Python functions.
 
    .. versionadded:: 3.12
 
+    - ``PyFunction_PYFUNC_EVENT_MODIFY_QUALNAME``
+
+   .. versionadded:: 3.15
 
 .. c:type:: int (*PyFunction_WatchCallback)(PyFunction_WatchEvent event, PyFunctionObject *func, PyObject *new_value)
 

Doc/tools/templates/download.html

@@ -75,16 +75,6 @@ <h1>{% trans %}Download Python {{ dl_version }} documentation{% endtrans %}</h1>
 See the <a href="https://docs.python.org/{{ version }}/archives/">directory listing</a>
 for file sizes.{% endtrans %}</p>
 
-<h2>{% trans %}Unpacking{% endtrans %}</h2>
-
-<p>{% trans %}Unix users should download the .tar.bz2 archives; these are bzipped tar
-archives and can be handled in the usual way using tar and the bzip2
-program. The <a href="https://infozip.sourceforge.net">Info-ZIP</a> unzip program can be
-used to handle the ZIP archives if desired. The .tar.bz2 archives provide the
-best compression and fastest download times.{% endtrans %}</p>
-
-<p>{% trans %}Windows users can use the ZIP archives since those are customary on that
-platform. These are created on Unix using the Info-ZIP zip program.{% endtrans %}</p>
 
 <h2>{% trans %}Problems{% endtrans %}</h2>
 {% set bugs = pathto('bugs') %}

Include/cpython/funcobject.h

@@ -134,7 +134,8 @@ PyAPI_FUNC(PyObject *) PyStaticMethod_New(PyObject *);
     V(DESTROY)                   \
     V(MODIFY_CODE)               \
     V(MODIFY_DEFAULTS)           \
-    V(MODIFY_KWDEFAULTS)
+    V(MODIFY_KWDEFAULTS)         \
+    V(MODIFY_QUALNAME)
 
 typedef enum {
     #define PY_DEF_EVENT(EVENT) PyFunction_EVENT_##EVENT,

Lib/pathlib/__init__.py

@@ -336,13 +336,8 @@ def _raw_path(self):
             return paths[0]
         elif paths:
             # Join path segments from the initializer.
-            path = self.parser.join(*paths)
-            # Cache the joined path.
-            paths.clear()
-            paths.append(path)
-            return path
+            return self.parser.join(*paths)
         else:
-            paths.append('')
             return ''
 
     @property
@@ -490,16 +485,19 @@ def relative_to(self, other, *, walk_up=False):
         """
         if not hasattr(other, 'with_segments'):
             other = self.with_segments(other)
-        for step, path in enumerate(chain([other], other.parents)):
+        parts = []
+        for path in chain([other], other.parents):
             if path == self or path in self.parents:
                 break
             elif not walk_up:
                 raise ValueError(f"{str(self)!r} is not in the subpath of {str(other)!r}")
             elif path.name == '..':
                 raise ValueError(f"'..' segment in {str(other)!r} cannot be walked")
+            else:
+                parts.append('..')
         else:
             raise ValueError(f"{str(self)!r} and {str(other)!r} have different anchors")
-        parts = ['..'] * step + self._tail[len(path._tail):]
+        parts.extend(self._tail[len(path._tail):])
         return self._from_parsed_parts('', '', parts)
 
     def is_relative_to(self, other):

Lib/pathlib/types.py

@@ -234,6 +234,33 @@ def parents(self):
             parent = split(path)[0]
         return tuple(parents)
 
+    def relative_to(self, other, *, walk_up=False):
+        """Return the relative path to another path identified by the passed
+        arguments.  If the operation is not possible (because this is not
+        related to the other path), raise ValueError.
+
+        The *walk_up* parameter controls whether `..` may be used to resolve
+        the path.
+        """
+        parts = []
+        for path in (other,) + other.parents:
+            if self.is_relative_to(path):
+                break
+            elif not walk_up:
+                raise ValueError(f"{self!r} is not in the subpath of {other!r}")
+            elif path.name == '..':
+                raise ValueError(f"'..' segment in {other!r} cannot be walked")
+            else:
+                parts.append('..')
+        else:
+            raise ValueError(f"{self!r} and {other!r} have different anchors")
+        return self.with_segments(*parts, *self.parts[len(path.parts):])
+
+    def is_relative_to(self, other):
+        """Return True if the path is relative to another path or False.
+        """
+        return other == self or other in self.parents
+
     def full_match(self, pattern):
         """
         Return True if this path matches the given glob-style pattern. The

Lib/test/test_capi/test_watchers.py

@@ -514,6 +514,10 @@ def myfunc():
             _testcapi.set_func_kwdefaults_via_capi(myfunc, new_kwdefaults)
             self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_KWDEFAULTS, myfunc, new_kwdefaults), events)
 
+            new_qualname = "foo.bar"
+            myfunc.__qualname__ = new_qualname
+            self.assertIn((_testcapi.PYFUNC_EVENT_MODIFY_QUALNAME, myfunc, new_qualname), events)
+
             # Clear events reference to func
             events = []
             del myfunc

Lib/test/test_pathlib/test_join.py

@@ -3,6 +3,8 @@
 """
 
 import unittest
+import threading
+from test.support import threading_helper
 
 from .support import is_pypi
 from .support.lexical_path import LexicalPath
@@ -158,6 +160,26 @@ def test_parts(self):
         parts = p.parts
         self.assertEqual(parts, (sep, 'a', 'b'))
 
+    @threading_helper.requires_working_threading()
+    def test_parts_multithreaded(self):
+        P = self.cls
+
+        NUM_THREADS = 10
+        NUM_ITERS = 10
+
+        for _ in range(NUM_ITERS):
+            b = threading.Barrier(NUM_THREADS)
+            path = P('a') / 'b' / 'c' / 'd' / 'e'
+            expected = ('a', 'b', 'c', 'd', 'e')
+
+            def check_parts():
+                b.wait()
+                self.assertEqual(path.parts, expected)
+
+            threads = [threading.Thread(target=check_parts) for _ in range(NUM_THREADS)]
+            with threading_helper.start_threads(threads):
+                pass
+
     def test_parent(self):
         # Relative
         P = self.cls
@@ -354,6 +376,61 @@ def test_with_suffix(self):
         self.assertRaises(ValueError, P('a/b').with_suffix, '.d/.')
         self.assertRaises(TypeError, P('a/b').with_suffix, None)
 
+    def test_relative_to(self):
+        P = self.cls
+        p = P('a/b')
+        self.assertEqual(p.relative_to(P('')), P('a', 'b'))
+        self.assertEqual(p.relative_to(P('a')), P('b'))
+        self.assertEqual(p.relative_to(P('a/b')), P(''))
+        self.assertEqual(p.relative_to(P(''), walk_up=True), P('a', 'b'))
+        self.assertEqual(p.relative_to(P('a'), walk_up=True), P('b'))
+        self.assertEqual(p.relative_to(P('a/b'), walk_up=True), P(''))
+        self.assertEqual(p.relative_to(P('a/c'), walk_up=True), P('..', 'b'))
+        self.assertEqual(p.relative_to(P('a/b/c'), walk_up=True), P('..'))
+        self.assertEqual(p.relative_to(P('c'), walk_up=True), P('..', 'a', 'b'))
+        self.assertRaises(ValueError, p.relative_to, P('c'))
+        self.assertRaises(ValueError, p.relative_to, P('a/b/c'))
+        self.assertRaises(ValueError, p.relative_to, P('a/c'))
+        self.assertRaises(ValueError, p.relative_to, P('/a'))
+        self.assertRaises(ValueError, p.relative_to, P('../a'))
+        self.assertRaises(ValueError, p.relative_to, P('a/..'))
+        self.assertRaises(ValueError, p.relative_to, P('/a/..'))
+        self.assertRaises(ValueError, p.relative_to, P('/'), walk_up=True)
+        self.assertRaises(ValueError, p.relative_to, P('/a'), walk_up=True)
+        self.assertRaises(ValueError, p.relative_to, P('../a'), walk_up=True)
+        self.assertRaises(ValueError, p.relative_to, P('a/..'), walk_up=True)
+        self.assertRaises(ValueError, p.relative_to, P('/a/..'), walk_up=True)
+        class Q(self.cls):
+            __eq__ = object.__eq__
+            __hash__ = object.__hash__
+        q = Q('a/b')
+        self.assertTrue(q.relative_to(q))
+        self.assertRaises(ValueError, q.relative_to, Q(''))
+        self.assertRaises(ValueError, q.relative_to, Q('a'))
+        self.assertRaises(ValueError, q.relative_to, Q('a'), walk_up=True)
+        self.assertRaises(ValueError, q.relative_to, Q('a/b'))
+        self.assertRaises(ValueError, q.relative_to, Q('c'))
+
+    def test_is_relative_to(self):
+        P = self.cls
+        p = P('a/b')
+        self.assertTrue(p.is_relative_to(P('')))
+        self.assertTrue(p.is_relative_to(P('a')))
+        self.assertTrue(p.is_relative_to(P('a/b')))
+        self.assertFalse(p.is_relative_to(P('c')))
+        self.assertFalse(p.is_relative_to(P('a/b/c')))
+        self.assertFalse(p.is_relative_to(P('a/c')))
+        self.assertFalse(p.is_relative_to(P('/a')))
+        class Q(self.cls):
+            __eq__ = object.__eq__
+            __hash__ = object.__hash__
+        q = Q('a/b')
+        self.assertTrue(q.is_relative_to(q))
+        self.assertFalse(q.is_relative_to(Q('')))
+        self.assertFalse(q.is_relative_to(Q('a')))
+        self.assertFalse(q.is_relative_to(Q('a/b')))
+        self.assertFalse(q.is_relative_to(Q('c')))
+
 
 class LexicalPathJoinTest(JoinTestBase, unittest.TestCase):
     cls = LexicalPath

Misc/NEWS.d/next/C_API/2025-10-10-20-59-07.gh-issue-139924.ALByCb.rst

@@ -0,0 +1 @@
+Function watchers can now receive a PyFunction_PYFUNC_EVENT_MODIFY_QUALNAME event when a watched functions qualname is changed.

Misc/NEWS.d/next/Library/2025-09-17-12-07-21.gh-issue-139001.O6tseN.rst

@@ -0,0 +1,2 @@
+Fix race condition in :class:`pathlib.Path` on the internal ``_raw_paths``
+field.

Objects/funcobject.c

@@ -62,6 +62,7 @@ handle_func_event(PyFunction_WatchEvent event, PyFunctionObject *func,
         case PyFunction_EVENT_MODIFY_CODE:
         case PyFunction_EVENT_MODIFY_DEFAULTS:
         case PyFunction_EVENT_MODIFY_KWDEFAULTS:
+        case PyFunction_EVENT_MODIFY_QUALNAME:
             RARE_EVENT_INTERP_INC(interp, func_modification);
             break;
         default:
@@ -747,6 +748,7 @@ func_set_qualname(PyObject *self, PyObject *value, void *Py_UNUSED(ignored))
                         "__qualname__ must be set to a string object");
         return -1;
     }
+    handle_func_event(PyFunction_EVENT_MODIFY_QUALNAME, (PyFunctionObject *) op, value);
     Py_XSETREF(op->func_qualname, Py_NewRef(value));
     return 0;
 }