https://github.com/python/cpython/commit/b2b68d40f887c8a9583a9b48babc40f25bc5e0e2
commit: b2b68d40f887c8a9583a9b48babc40f25bc5e0e2
branch: main
author: Serhiy Storchaka <[email protected]>
committer: serhiy-storchaka <[email protected]>
date: 2025-11-13T19:48:52+02:00
summary:
gh-140873: Add support of non-descriptor callables in
functools.singledispatchmethod() (GH-140884)
files:
A Misc/NEWS.d/next/Library/2025-11-01-14-44-09.gh-issue-140873.kfuc9B.rst
M Doc/library/functools.rst
M Doc/whatsnew/3.15.rst
M Lib/functools.py
M Lib/test/test_functools.py
diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst
index 1d9ac328f32769..b2e2e11c0dc414 100644
--- a/Doc/library/functools.rst
+++ b/Doc/library/functools.rst
@@ -672,7 +672,7 @@ The :mod:`functools` module defines the following functions:
dispatch>` :term:`generic function`.
To define a generic method, decorate it with the ``@singledispatchmethod``
- decorator. When defining a function using ``@singledispatchmethod``, note
+ decorator. When defining a method using ``@singledispatchmethod``, note
that the dispatch happens on the type of the first non-*self* or non-*cls*
argument::
@@ -716,6 +716,9 @@ The :mod:`functools` module defines the following functions:
.. versionadded:: 3.8
+ .. versionchanged:: next
+ Added support of non-:term:`descriptor` callables.
+
.. function:: update_wrapper(wrapper, wrapped, assigned=WRAPPER_ASSIGNMENTS,
updated=WRAPPER_UPDATES)
diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst
index b360ad964cf17f..895616e3049a50 100644
--- a/Doc/whatsnew/3.15.rst
+++ b/Doc/whatsnew/3.15.rst
@@ -498,6 +498,14 @@ difflib
(Contributed by Jiahao Li in :gh:`134580`.)
+functools
+---------
+
+* :func:`~functools.singledispatchmethod` now supports non-:term:`descriptor`
+ callables.
+ (Contributed by Serhiy Storchaka in :gh:`140873`.)
+
+
hashlib
-------
diff --git a/Lib/functools.py b/Lib/functools.py
index a92844ba7227b0..8063eb5ffc3304 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -1083,7 +1083,10 @@ def __call__(self, /, *args, **kwargs):
'singledispatchmethod method')
raise TypeError(f'{funcname} requires at least '
'1 positional argument')
- return self._dispatch(args[0].__class__).__get__(self._obj,
self._cls)(*args, **kwargs)
+ method = self._dispatch(args[0].__class__)
+ if hasattr(method, "__get__"):
+ method = method.__get__(self._obj, self._cls)
+ return method(*args, **kwargs)
def __getattr__(self, name):
# Resolve these attributes lazily to speed up creation of
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index ce9e7f6d57dd3c..090926fd8d8b61 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -2785,7 +2785,7 @@ class Slot:
@functools.singledispatchmethod
@classmethod
def go(cls, item, arg):
- pass
+ return item - arg
@go.register
@classmethod
@@ -2794,7 +2794,9 @@ def _(cls, item: int, arg):
s = Slot()
self.assertEqual(s.go(1, 1), 2)
+ self.assertEqual(s.go(1.5, 1), 0.5)
self.assertEqual(Slot.go(1, 1), 2)
+ self.assertEqual(Slot.go(1.5, 1), 0.5)
def test_staticmethod_slotted_class(self):
class A:
@@ -3485,6 +3487,37 @@ def _(item, arg: bytes) -> str:
self.assertEqual(str(Signature.from_callable(A.static_func)),
'(item, arg: int) -> str')
+ def test_method_non_descriptor(self):
+ class Callable:
+ def __init__(self, value):
+ self.value = value
+ def __call__(self, arg):
+ return self.value, arg
+
+ class A:
+ t = functools.singledispatchmethod(Callable('general'))
+ t.register(int, Callable('special'))
+
+ @functools.singledispatchmethod
+ def u(self, arg):
+ return 'general', arg
+ u.register(int, Callable('special'))
+
+ v = functools.singledispatchmethod(Callable('general'))
+ @v.register(int)
+ def _(self, arg):
+ return 'special', arg
+
+ a = A()
+ self.assertEqual(a.t(0), ('special', 0))
+ self.assertEqual(a.t(2.5), ('general', 2.5))
+ self.assertEqual(A.t(0), ('special', 0))
+ self.assertEqual(A.t(2.5), ('general', 2.5))
+ self.assertEqual(a.u(0), ('special', 0))
+ self.assertEqual(a.u(2.5), ('general', 2.5))
+ self.assertEqual(a.v(0), ('special', 0))
+ self.assertEqual(a.v(2.5), ('general', 2.5))
+
class CachedCostItem:
_cost = 1
diff --git
a/Misc/NEWS.d/next/Library/2025-11-01-14-44-09.gh-issue-140873.kfuc9B.rst
b/Misc/NEWS.d/next/Library/2025-11-01-14-44-09.gh-issue-140873.kfuc9B.rst
new file mode 100644
index 00000000000000..e15057640646d6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-11-01-14-44-09.gh-issue-140873.kfuc9B.rst
@@ -0,0 +1,2 @@
+Add support of non-:term:`descriptor` callables in
+:func:`functools.singledispatchmethod`.
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