[pull] main from python:main

Doc/c-api/frame.rst

@@ -269,29 +269,8 @@ Unless using :pep:`523`, you will not need this.
       * - .. c:macro:: PyUnstable_EXECUTABLE_KIND_METHOD_DESCRIPTOR
         - The frame corresponds to a method on a class instance.
 
-   However, Python's C API lacks a function to read the executable kind from
-   a frame. Instead, use this recipe:
-
-   .. code-block:: c
-
-      int
-      get_executable_kind(PyFrameObject *frame)
-      {
-         _PyInterpreterFrame *f = frame->f_frame;
-         PyObject *exec = PyStackRef_AsPyObjectBorrow(f->f_executable);
-
-         if (PyCode_Check(exec)) {
-            return PyUnstable_EXECUTABLE_KIND_PY_FUNCTION;
-         }
-         if (PyMethod_Check(exec)) {
-            return PyUnstable_EXECUTABLE_KIND_BUILTIN_FUNCTION;
-         }
-         if (Py_IS_TYPE(exec, &PyMethodDescr_Type)) {
-            return PyUnstable_EXECUTABLE_KIND_METHOD_DESCRIPTOR;
-         }
-
-         return PyUnstable_EXECUTABLE_KIND_SKIP;
-      }
+   Note that reading the executable kind from a frame is currently only
+   possible with undocumented internal APIs.
 
    .. versionadded:: 3.13
 

Doc/library/argparse.rst

@@ -1679,6 +1679,12 @@ The Namespace object
    Simple class used by default by :meth:`~ArgumentParser.parse_args` to create
    an object holding attributes and return it.
 
+   :class:`!Namespace` objects support :func:`copy.replace`,
+   which returns a copy of the object with the specified attributes replaced.
+
+   .. versionchanged:: next
+      Added support for :func:`copy.replace`.
+
    This class is deliberately simple, just an :class:`object` subclass with a
    readable string representation. If you prefer to have dict-like view of the
    attributes, you can use the standard Python idiom, :func:`vars`::

Doc/library/ast.rst

@@ -806,7 +806,8 @@ Comprehensions
    List and set comprehensions, generator expressions, and dictionary
    comprehensions. ``elt`` (or ``key`` and ``value``) is a single node
    representing the part that will be evaluated for each item.
-
+   For dictionary comprehensions using unpacking, for example
+   ``{**item for item in items}``, ``value`` is ``None``,
    ``generators`` is a list of :class:`comprehension` nodes.
 
    .. doctest::

Doc/library/dis.rst

@@ -1899,25 +1899,29 @@ iterations of the loop.
 
    The operand determines which intrinsic function is called:
 
-   +----------------------------------------+-----------------------------------+
-   | Operand                                | Description                       |
-   +========================================+===================================+
-   | ``INTRINSIC_2_INVALID``                | Not valid                         |
-   +----------------------------------------+-----------------------------------+
-   | ``INTRINSIC_PREP_RERAISE_STAR``        | Calculates the                    |
-   |                                        | :exc:`ExceptionGroup` to raise    |
-   |                                        | from a ``try-except*``.           |
-   +----------------------------------------+-----------------------------------+
-   | ``INTRINSIC_TYPEVAR_WITH_BOUND``       | Creates a :class:`typing.TypeVar` |
-   |                                        | with a bound.                     |
-   +----------------------------------------+-----------------------------------+
-   | ``INTRINSIC_TYPEVAR_WITH_CONSTRAINTS`` | Creates a                         |
-   |                                        | :class:`typing.TypeVar` with      |
-   |                                        | constraints.                      |
-   +----------------------------------------+-----------------------------------+
-   | ``INTRINSIC_SET_FUNCTION_TYPE_PARAMS`` | Sets the ``__type_params__``      |
-   |                                        | attribute of a function.          |
-   +----------------------------------------+-----------------------------------+
+   +------------------------------------------+-----------------------------------+
+   | Operand                                  | Description                       |
+   +==========================================+===================================+
+   | ``INTRINSIC_2_INVALID``                  | Not valid                         |
+   +------------------------------------------+-----------------------------------+
+   | ``INTRINSIC_PREP_RERAISE_STAR``          | Calculates the                    |
+   |                                          | :exc:`ExceptionGroup` to raise    |
+   |                                          | from a ``try-except*``.           |
+   +------------------------------------------+-----------------------------------+
+   | ``INTRINSIC_TYPEVAR_WITH_BOUND``         | Creates a :class:`typing.TypeVar` |
+   |                                          | with a bound.                     |
+   +------------------------------------------+-----------------------------------+
+   | ``INTRINSIC_TYPEVAR_WITH_CONSTRAINTS``   | Creates a                         |
+   |                                          | :class:`typing.TypeVar` with      |
+   |                                          | constraints.                      |
+   +------------------------------------------+-----------------------------------+
+   | ``INTRINSIC_SET_FUNCTION_TYPE_PARAMS``   | Sets the ``__type_params__``      |
+   |                                          | attribute of a function.          |
+   +------------------------------------------+-----------------------------------+
+   | ``INTRINSIC_ADD_CONDITIONAL_ANNOTATION`` | Adds an annotation index to the   |
+   |                                          | ``__conditional_annotations__``   |
+   |                                          | set.                              |
+   +------------------------------------------+-----------------------------------+
 
    .. versionadded:: 3.12
 

Include/internal/pycore_intrinsics.h

@@ -30,8 +30,9 @@
 #define INTRINSIC_TYPEVAR_WITH_CONSTRAINTS       3
 #define INTRINSIC_SET_FUNCTION_TYPE_PARAMS       4
 #define INTRINSIC_SET_TYPEPARAM_DEFAULT          5
+#define INTRINSIC_ADD_CONDITIONAL_ANNOTATION     6
 
-#define MAX_INTRINSIC_2                          5
+#define MAX_INTRINSIC_2                          6
 
 typedef PyObject *(*intrinsic_func1)(PyThreadState* tstate, PyObject *value);
 typedef PyObject *(*intrinsic_func2)(PyThreadState* tstate, PyObject *value1, PyObject *value2);

Include/internal/pycore_magic_number.h

@@ -302,7 +302,7 @@ Known values:
     Python 3.16a1 3702 (Replace DELETE_NAME with PUSH_NULL; STORE_NAME)
     Python 3.16a1 3703 (Replace DELETE_GLOBAL with PUSH_NULL; STORE_GLOBAL)
     Python 3.16a1 3704 (Replace DELETE_ATTR with PUSH_NULL; STORE_ATTR)
-
+    Python 3.16a1 3705 (Add INTRINSIC_ADD_CONDITIONAL_ANNOTATION)
 
     Python 3.17 will start with 3750
 
@@ -312,7 +312,7 @@ Known values:
 
 */
 
-#define PYC_MAGIC_NUMBER 3704
+#define PYC_MAGIC_NUMBER 3705
 /* This is equivalent to converting PYC_MAGIC_NUMBER to 2 bytes
    (little-endian) and then appending b'\r\n'. */
 #define PYC_MAGIC_NUMBER_TOKEN \

Lib/argparse.py

@@ -1545,6 +1545,12 @@ def __eq__(self, other):
     def __contains__(self, key):
         return key in self.__dict__
 
+    def __replace__(self, /, **changes):
+        new = self.__class__()
+        new.__dict__.update(self.__dict__)
+        new.__dict__.update(changes)
+        return new
+
 
 class _ActionsContainer(object):
 

Lib/test/test_argparse.py

@@ -2,6 +2,7 @@
 
 import _colorize
 import contextlib
+import copy
 import functools
 import io
 import operator
@@ -6267,6 +6268,19 @@ def test_equality_returns_notimplemented(self):
         self.assertIs(ns.__eq__(None), NotImplemented)
         self.assertIs(ns.__ne__(None), NotImplemented)
 
+    def test_replace(self):
+        ns = argparse.Namespace(a=1, b=2)
+        new = copy.replace(ns, b=3, c=4)
+        self.assertIsInstance(new, argparse.Namespace)
+        self.assertEqual(new, argparse.Namespace(a=1, b=3, c=4))
+        self.assertEqual(ns, argparse.Namespace(a=1, b=2))
+
+        class MyNamespace(argparse.Namespace):
+            pass
+        new = copy.replace(MyNamespace(a=1), a=2)
+        self.assertIsInstance(new, MyNamespace)
+        self.assertEqual(new.a, 2)
+
 
 # ===================
 # File encoding tests

Lib/test/test_dis.py

@@ -395,12 +395,12 @@ def wrap_func_w_kwargs():
                STORE_NAME               1 (x)
                LOAD_NAME                0 (__conditional_annotations__)
                LOAD_SMALL_INT           0
-               SET_ADD                  1
+               CALL_INTRINSIC_2         6 (INTRINSIC_ADD_CONDITIONAL_ANNOTATION)
                POP_TOP
 
    3           LOAD_NAME                0 (__conditional_annotations__)
                LOAD_SMALL_INT           1
-               SET_ADD                  1
+               CALL_INTRINSIC_2         6 (INTRINSIC_ADD_CONDITIONAL_ANNOTATION)
                POP_TOP
 
    4           LOAD_SMALL_INT           1

Lib/test/test_type_annotations.py

@@ -1,5 +1,6 @@
 import annotationlib
 import inspect
+import itertools
 import textwrap
 import types
 import unittest
@@ -896,3 +897,18 @@ class Generic:
                 mod = build_module(code)
                 annos = mod.__annotations__
                 self.assertEqual(annos, {"annotated_name": 0})
+
+    # gh-154902
+    def test_conditional_annotations_rebound(self):
+        # user code can rebind __conditional_annotations__ to any object
+        lefts = ("__conditional_annotations__",
+                 'globals()["__conditional_annotations__"]')
+        values = ("0", "{}", "[]", "''", "object()", "frozenset()")
+        for left, value in itertools.product(lefts, values):
+            with self.subTest(left=left, value=value):
+                code = f"""
+                    {left} = {value}
+                    x: int
+                """
+                with self.assertRaises(TypeError):
+                    run_code(code)

Misc/NEWS.d/next/Core_and_Builtins/2026-08-01-15-07-10.gh-issue-154902.DIi6sf.rst

@@ -0,0 +1,2 @@
+Fix a crash when ``__conditional_annotations__`` is rebound to a non-set
+object.

Misc/NEWS.d/next/Library/2026-08-01-19-04-00.gh-issue-155043.Ar1Nsp.rst

@@ -0,0 +1 @@
+:class:`argparse.Namespace` objects now support :func:`copy.replace`.