[3.14] gh-138859: Account for ParamSpec defaults that are not lists … (GH-138868) (#140207)

gh-138859: Account for `ParamSpec` defaults that are not lists … (GH-138868)
(cherry picked from commit 379fd020a0)

Co-authored-by: bzoracler <50305397+bzoracler@users.noreply.github.com>

Doc/library/importlib.rst

@@ -1253,7 +1253,7 @@ find and load modules.
    To accommodate this requirement, when running on iOS, extension module
    binaries are *not* packaged as ``.so`` files on ``sys.path``, but as
    individual standalone frameworks. To discover those frameworks, this loader
-   is be registered against the ``.fwork`` file extension, with a ``.fwork``
+   is registered against the ``.fwork`` file extension, with a ``.fwork``
    file acting as a placeholder in the original location of the binary on
    ``sys.path``. The ``.fwork`` file contains the path of the actual binary in
    the ``Frameworks`` folder, relative to the app bundle. To allow for

Doc/library/stdtypes.rst

@@ -5944,7 +5944,7 @@ It is written as ``None``.
 The Ellipsis Object
 -------------------
 
-This object is commonly used used to indicate that something is omitted.
+This object is commonly used to indicate that something is omitted.
 It supports no special operations.  There is exactly one ellipsis object, named
 :const:`Ellipsis` (a built-in name).  ``type(Ellipsis)()`` produces the
 :const:`Ellipsis` singleton.

Doc/library/tkinter.rst

@@ -392,7 +392,7 @@ by spaces. Without getting into too many details, notice the following:
 * Operations which are implemented as separate *commands* in Tcl (like
   ``grid`` or ``destroy``) are represented as *methods* on Tkinter widget
   objects. As you'll see shortly, at other times Tcl uses what appear to be
-  method calls on widget objects, which more closely mirror what would is
+  method calls on widget objects, which more closely mirror what is
   used in Tkinter.
 
 

Doc/whatsnew/3.14.rst

@@ -1140,7 +1140,7 @@ concurrent.futures
 .. _whatsnew314-concurrent-futures-start-method:
 
 * On Unix platforms other than macOS, :ref:`'forkserver'
-  <multiprocessing-start-method-forkserver>` is now the the default :ref:`start
+  <multiprocessing-start-method-forkserver>` is now the default :ref:`start
   method <multiprocessing-start-methods>` for
   :class:`~concurrent.futures.ProcessPoolExecutor`
   (replacing :ref:`'fork' <multiprocessing-start-method-fork>`).
@@ -1591,7 +1591,7 @@ multiprocessing
 .. _whatsnew314-multiprocessing-start-method:
 
 * On Unix platforms other than macOS, :ref:`'forkserver'
-  <multiprocessing-start-method-forkserver>` is now the the default :ref:`start
+  <multiprocessing-start-method-forkserver>` is now the default :ref:`start
   method <multiprocessing-start-methods>`
   (replacing :ref:`'fork' <multiprocessing-start-method-fork>`).
   This change does not affect Windows or macOS, where :ref:`'spawn'

Lib/test/test_typing.py

@@ -762,6 +762,16 @@ class A(Generic[T, P, U]): ...
         self.assertEqual(A[float, [range]].__args__, (float, (range,), float))
         self.assertEqual(A[float, [range], int].__args__, (float, (range,), int))
 
+    def test_paramspec_and_typevar_specialization_2(self):
+        T = TypeVar("T")
+        P = ParamSpec('P', default=...)
+        U = TypeVar("U", default=float)
+        self.assertEqual(P.__default__, ...)
+        class A(Generic[T, P, U]): ...
+        self.assertEqual(A[float].__args__, (float, ..., float))
+        self.assertEqual(A[float, [range]].__args__, (float, (range,), float))
+        self.assertEqual(A[float, [range], int].__args__, (float, (range,), int))
+
     def test_typevartuple_none(self):
         U = TypeVarTuple('U')
         U_None = TypeVarTuple('U_None', default=None)

Lib/typing.py

@@ -1097,7 +1097,7 @@ def _paramspec_prepare_subst(self, alias, args):
     params = alias.__parameters__
     i = params.index(self)
     if i == len(args) and self.has_default():
-        args = [*args, self.__default__]
+        args = (*args, self.__default__)
     if i >= len(args):
         raise TypeError(f"Too few arguments for {alias}")
     # Special case where Z[[int, str, bool]] == Z[int, str, bool] in PEP 612.

Misc/NEWS.d/next/Library/2025-09-13-12-19-17.gh-issue-138859.PxjIoN.rst

@@ -0,0 +1 @@
+Fix generic type parameterization raising a :exc:`TypeError` when omitting a :class:`ParamSpec` that has a default which is not a list of types.