Update functools from 3.13.9 (#6205)

* Update `functools.py` from 3.13.9

* mark/unmark tests

Lib/functools.py

@@ -19,8 +19,9 @@ from collections import namedtuple
 # import types, weakref  # Deferred to single_dispatch()
 from reprlib import recursive_repr
 from _thread import RLock
-from types import GenericAlias
 
+# Avoid importing types, so we can speedup import time
+GenericAlias = type(list[int])
 
 ################################################################################
 ### update_wrapper() and wraps() decorator
@@ -236,14 +237,16 @@ _initial_missing = object()
 
 def reduce(function, sequence, initial=_initial_missing):
     """
-    reduce(function, iterable[, initial]) -> value
+    reduce(function, iterable[, initial], /) -> value
 
-    Apply a function of two arguments cumulatively to the items of a sequence
-    or iterable, from left to right, so as to reduce the iterable to a single
-    value.  For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates
-    ((((1+2)+3)+4)+5).  If initial is present, it is placed before the items
-    of the iterable in the calculation, and serves as a default when the
-    iterable is empty.
+    Apply a function of two arguments cumulatively to the items of an iterable, from left to right.
+
+    This effectively reduces the iterable to a single value.  If initial is present,
+    it is placed before the items of the iterable in the calculation, and serves as
+    a default when the iterable is empty.
+
+    For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5])
+    calculates ((((1 + 2) + 3) + 4) + 5).
     """
 
     it = iter(sequence)
@@ -284,7 +287,7 @@ class partial:
         if not callable(func):
             raise TypeError("the first argument must be callable")
 
-        if hasattr(func, "func"):
+        if isinstance(func, partial):
             args = func.args + args
             keywords = {**func.keywords, **keywords}
             func = func.func
@@ -302,13 +305,23 @@ class partial:
 
     @recursive_repr()
     def __repr__(self):
-        qualname = type(self).__qualname__
+        cls = type(self)
+        qualname = cls.__qualname__
+        module = cls.__module__
         args = [repr(self.func)]
         args.extend(repr(x) for x in self.args)
         args.extend(f"{k}={v!r}" for (k, v) in self.keywords.items())
-        if type(self).__module__ == "functools":
-            return f"functools.{qualname}({', '.join(args)})"
-        return f"{qualname}({', '.join(args)})"
+        return f"{module}.{qualname}({', '.join(args)})"
+
+    def __get__(self, obj, objtype=None):
+        if obj is None:
+            return self
+        import warnings
+        warnings.warn('functools.partial will be a method descriptor in '
+                      'future Python versions; wrap it in staticmethod() '
+                      'if you want to preserve the old behavior',
+                      FutureWarning, 2)
+        return self
 
     def __reduce__(self):
         return type(self), (self.func,), (self.func, self.args,
@@ -338,6 +351,9 @@ class partial:
         self.args = args
         self.keywords = kwds
 
+    __class_getitem__ = classmethod(GenericAlias)
+
+
 try:
     from _functools import partial
 except ImportError:
@@ -372,28 +388,26 @@ class partialmethod(object):
             self.keywords = keywords
 
     def __repr__(self):
-        args = ", ".join(map(repr, self.args))
-        keywords = ", ".join("{}={!r}".format(k, v)
-                                 for k, v in self.keywords.items())
-        format_string = "{module}.{cls}({func}, {args}, {keywords})"
-        return format_string.format(module=self.__class__.__module__,
-                                    cls=self.__class__.__qualname__,
-                                    func=self.func,
-                                    args=args,
-                                    keywords=keywords)
+        cls = type(self)
+        module = cls.__module__
+        qualname = cls.__qualname__
+        args = [repr(self.func)]
+        args.extend(map(repr, self.args))
+        args.extend(f"{k}={v!r}" for k, v in self.keywords.items())
+        return f"{module}.{qualname}({', '.join(args)})"
 
     def _make_unbound_method(self):
         def _method(cls_or_self, /, *args, **keywords):
             keywords = {**self.keywords, **keywords}
             return self.func(cls_or_self, *self.args, *args, **keywords)
         _method.__isabstractmethod__ = self.__isabstractmethod__
-        _method._partialmethod = self
+        _method.__partialmethod__ = self
         return _method
 
     def __get__(self, obj, cls=None):
         get = getattr(self.func, "__get__", None)
         result = None
-        if get is not None:
+        if get is not None and not isinstance(self.func, partial):
             new_func = get(obj, cls)
             if new_func is not self.func:
                 # Assume __get__ returning something new indicates the
@@ -423,6 +437,17 @@ def _unwrap_partial(func):
         func = func.func
     return func
 
+def _unwrap_partialmethod(func):
+    prev = None
+    while func is not prev:
+        prev = func
+        while isinstance(getattr(func, "__partialmethod__", None), partialmethod):
+            func = func.__partialmethod__
+        while isinstance(func, partialmethod):
+            func = getattr(func, 'func')
+        func = _unwrap_partial(func)
+    return func
+
 ################################################################################
 ### LRU Cache function decorator
 ################################################################################
@@ -483,8 +508,9 @@ def lru_cache(maxsize=128, typed=False):
     can grow without bound.
 
     If *typed* is True, arguments of different types will be cached separately.
-    For example, f(3.0) and f(3) will be treated as distinct calls with
-    distinct results.
+    For example, f(decimal.Decimal("3.0")) and f(3.0) will be treated as
+    distinct calls with distinct results. Some types such as str and int may
+    be cached separately even when typed is false.
 
     Arguments to the cached function must be hashable.
 
@@ -660,7 +686,7 @@ def cache(user_function, /):
 def _c3_merge(sequences):
     """Merges MROs in *sequences* to a single MRO using the C3 algorithm.
 
-    Adapted from https://www.python.org/download/releases/2.3/mro/.
+    Adapted from https://docs.python.org/3/howto/mro.html.
 
     """
     result = []
@@ -905,7 +931,6 @@ def singledispatch(func):
         if not args:
             raise TypeError(f'{funcname} requires at least '
                             '1 positional argument')
-
         return dispatch(args[0].__class__)(*args, **kw)
 
     funcname = getattr(func, '__name__', 'singledispatch function')
@@ -941,13 +966,18 @@ class singledispatchmethod:
         return self.dispatcher.register(cls, func=method)
 
     def __get__(self, obj, cls=None):
+        dispatch = self.dispatcher.dispatch
+        funcname = getattr(self.func, '__name__', 'singledispatchmethod method')
         def _method(*args, **kwargs):
-            method = self.dispatcher.dispatch(args[0].__class__)
-            return method.__get__(obj, cls)(*args, **kwargs)
+            if not args:
+                raise TypeError(f'{funcname} requires at least '
+                                '1 positional argument')
+            return dispatch(args[0].__class__).__get__(obj, cls)(*args, **kwargs)
 
         _method.__isabstractmethod__ = self.__isabstractmethod__
         _method.register = self.register
         update_wrapper(_method, self.func)
+
         return _method
 
     @property
@@ -966,6 +996,7 @@ class cached_property:
         self.func = func
         self.attrname = None
         self.__doc__ = func.__doc__
+        self.__module__ = func.__module__
 
     def __set_name__(self, owner, name):
         if self.attrname is None:

Lib/test/test_functools.py

@@ -31,10 +31,6 @@ c_functools = import_helper.import_fresh_module('functools',
 
 decimal = import_helper.import_fresh_module('decimal', fresh=['_decimal'])
 
-_partial_types = [py_functools.partial]
-if c_functools:
-    _partial_types.append(c_functools.partial)
-
 
 @contextlib.contextmanager
 def replaced_module(name, replacement):
@@ -189,6 +185,19 @@ class TestPartial:
         flat = partial(signature, 'asdf', bar=True)
         self.assertEqual(signature(nested), signature(flat))
 
+    def test_nested_optimization_bug(self):
+        partial = self.partial
+        class Builder:
+            def __call__(self, tag, *children, **attrib):
+                return (tag, children, attrib)
+
+            def __getattr__(self, tag):
+                return partial(self, tag)
+
+        B = Builder()
+        m = B.m
+        assert m(1, 2, a=2) == ('m', (1, 2), dict(a=2))
+
     def test_nested_partial_with_attribute(self):
         # see issue 25137
         partial = self.partial
@@ -207,10 +216,7 @@ class TestPartial:
         kwargs = {'a': object(), 'b': object()}
         kwargs_reprs = ['a={a!r}, b={b!r}'.format_map(kwargs),
                         'b={b!r}, a={a!r}'.format_map(kwargs)]
-        if self.partial in _partial_types:
-            name = 'functools.partial'
-        else:
-            name = self.partial.__name__
+        name = f"{self.partial.__module__}.{self.partial.__qualname__}"
 
         f = self.partial(capture)
         self.assertEqual(f'{name}({capture!r})', repr(f))
@@ -229,10 +235,7 @@ class TestPartial:
                        for kwargs_repr in kwargs_reprs])
 
     def test_recursive_repr(self):
-        if self.partial in _partial_types:
-            name = 'functools.partial'
-        else:
-            name = self.partial.__name__
+        name = f"{self.partial.__module__}.{self.partial.__qualname__}"
 
         f = self.partial(capture)
         f.__setstate__((f, (), {}, {}))
@@ -344,8 +347,10 @@ class TestPartial:
             f.__setstate__((f, (), {}, {}))
             try:
                 for proto in range(pickle.HIGHEST_PROTOCOL + 1):
-                    with self.assertRaises(RecursionError):
-                        pickle.dumps(f, proto)
+                    # gh-117008: Small limit since pickle uses C stack memory
+                    with support.infinite_recursion(100):
+                        with self.assertRaises(RecursionError):
+                            pickle.dumps(f, proto)
             finally:
                 f.__setstate__((capture, (), {}, {}))
 
@@ -390,6 +395,30 @@ class TestPartial:
         f = self.partial(object)
         self.assertRaises(TypeError, f.__setstate__, BadSequence())
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_partial_as_method(self):
+        class A:
+            meth = self.partial(capture, 1, a=2)
+            cmeth = classmethod(self.partial(capture, 1, a=2))
+            smeth = staticmethod(self.partial(capture, 1, a=2))
+
+        a = A()
+        self.assertEqual(A.meth(3, b=4), ((1, 3), {'a': 2, 'b': 4}))
+        self.assertEqual(A.cmeth(3, b=4), ((1, A, 3), {'a': 2, 'b': 4}))
+        self.assertEqual(A.smeth(3, b=4), ((1, 3), {'a': 2, 'b': 4}))
+        with self.assertWarns(FutureWarning) as w:
+            self.assertEqual(a.meth(3, b=4), ((1, 3), {'a': 2, 'b': 4}))
+        self.assertEqual(w.filename, __file__)
+        self.assertEqual(a.cmeth(3, b=4), ((1, A, 3), {'a': 2, 'b': 4}))
+        self.assertEqual(a.smeth(3, b=4), ((1, 3), {'a': 2, 'b': 4}))
+
+    def test_partial_genericalias(self):
+        alias = self.partial[int]
+        self.assertIs(alias.__origin__, self.partial)
+        self.assertEqual(alias.__args__, (int,))
+        self.assertEqual(alias.__parameters__, ())
+
+
 @unittest.skipUnless(c_functools, 'requires the C _functools module')
 class TestPartialC(TestPartial, unittest.TestCase):
     if c_functools:
@@ -436,6 +465,14 @@ class TestPartialC(TestPartial, unittest.TestCase):
         self.assertIn('astr', r)
         self.assertIn("['sth']", r)
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_repr(self):
+        return super().test_repr()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_recursive_repr(self):
+        return super().test_recursive_repr()
+
 
 class TestPartialPy(TestPartial, unittest.TestCase):
     module = py_functools
@@ -454,14 +491,6 @@ class TestPartialCSubclass(TestPartialC):
     if c_functools:
         partial = CPartialSubclass
 
-    # TODO: RUSTPYTHON
-    def test_pickle(self):
-        TestPartial.test_pickle(self)
-
-    # TODO: RUSTPYTHON
-    def test_recursive_pickle(self):
-        TestPartial.test_recursive_pickle(self)
-
     # partial subclasses are not optimized for nested calls
     test_nested_optimization = None
 
@@ -572,6 +601,14 @@ class TestPartialMethod(unittest.TestCase):
                 method = functools.partialmethod(func=capture, a=1)
 
     def test_repr(self):
+        self.assertEqual(repr(vars(self.A)['nothing']),
+                         'functools.partialmethod({})'.format(capture))
+        self.assertEqual(repr(vars(self.A)['positional']),
+                         'functools.partialmethod({}, 1)'.format(capture))
+        self.assertEqual(repr(vars(self.A)['keywords']),
+                         'functools.partialmethod({}, a=2)'.format(capture))
+        self.assertEqual(repr(vars(self.A)['spec_keywords']),
+                         'functools.partialmethod({}, self=1, func=2)'.format(capture))
         self.assertEqual(repr(vars(self.A)['both']),
                          'functools.partialmethod({}, 3, b=4)'.format(capture))
 
@@ -620,9 +657,7 @@ class TestUpdateWrapper(unittest.TestCase):
 
 
     def _default_update(self):
-        # XXX: RUSTPYTHON; f[T] is not supported yet
-        # def f[T](a:'This is a new annotation'):
-        def f(a:'This is a new annotation'):
+        def f[T](a:'This is a new annotation'):
             """This is a test"""
             pass
         f.attr = 'This is also a test'
@@ -632,8 +667,6 @@ class TestUpdateWrapper(unittest.TestCase):
         functools.update_wrapper(wrapper, f)
         return wrapper, f
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_default_update(self):
         wrapper, f = self._default_update()
         self.check_wrapper(wrapper, f)
@@ -717,6 +750,14 @@ class TestUpdateWrapper(unittest.TestCase):
         self.assertTrue(wrapper.__doc__.startswith('max('))
         self.assertEqual(wrapper.__annotations__, {})
 
+    def test_update_type_wrapper(self):
+        def wrapper(*args): pass
+
+        functools.update_wrapper(wrapper, type)
+        self.assertEqual(wrapper.__name__, 'type')
+        self.assertEqual(wrapper.__annotations__, {})
+        self.assertEqual(wrapper.__type_params__, ())
+
 
 class TestWraps(TestUpdateWrapper):
 
@@ -951,9 +992,16 @@ class TestCmpToKey:
         self.assertRaises(TypeError, hash, k)
         self.assertNotIsInstance(k, collections.abc.Hashable)
 
+    @unittest.skipIf(support.MISSING_C_DOCSTRINGS,
+                     "Signature information for builtins requires docstrings")
     def test_cmp_to_signature(self):
-        self.assertEqual(str(Signature.from_callable(self.cmp_to_key)),
-                         '(mycmp)')
+        sig = Signature.from_callable(self.cmp_to_key)
+        self.assertEqual(str(sig), '(mycmp)')
+        def mycmp(x, y):
+            return y - x
+        sig = Signature.from_callable(self.cmp_to_key(mycmp))
+        self.assertEqual(str(sig), '(obj)')
+
 
 
 @unittest.skipUnless(c_functools, 'requires the C _functools module')
@@ -961,46 +1009,6 @@ class TestCmpToKeyC(TestCmpToKey, unittest.TestCase):
     if c_functools:
         cmp_to_key = c_functools.cmp_to_key
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_bad_cmp(self):
-        super().test_bad_cmp()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_cmp_to_key(self):
-        super().test_cmp_to_key()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_cmp_to_key_arguments(self):
-        super().test_cmp_to_key_arguments()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_hash(self):
-        super().test_hash()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_obj_field(self):
-        super().test_obj_field()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_sort_int(self):
-        super().test_sort_int()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_sort_int_str(self):
-        super().test_sort_int_str()
-
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
-    def test_cmp_to_signature(self):
-        super().test_cmp_to_signature()
-
     @support.cpython_only
     def test_disallow_instantiation(self):
         # Ensure that the type disallows instantiation (bpo-43916)
@@ -1008,6 +1016,38 @@ class TestCmpToKeyC(TestCmpToKey, unittest.TestCase):
             self, type(c_functools.cmp_to_key(None))
         )
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_bad_cmp(self):
+        return super().test_bad_cmp()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_cmp_to_key(self):
+        return super().test_cmp_to_key()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_cmp_to_key_arguments(self):
+        return super().test_cmp_to_key_arguments()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_cmp_to_signature(self):
+        return super().test_cmp_to_signature()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_hash(self):
+        return super().test_hash()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_obj_field(self):
+        return super().test_obj_field()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_sort_int(self):
+        return super().test_sort_int()
+
+    @unittest.expectedFailure # TODO: RUSTPYTHON
+    def test_sort_int_str(self):
+        return super().test_sort_int_str()
+
 
 class TestCmpToKeyPy(TestCmpToKey, unittest.TestCase):
     cmp_to_key = staticmethod(py_functools.cmp_to_key)
@@ -1340,6 +1380,16 @@ class TestCache:
             self.module._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
 
 
+class TestCachePy(TestCache, unittest.TestCase):
+    module = py_functools
+
+
+@unittest.skipUnless(c_functools, 'requires the C _functools module')
+class TestCacheC(TestCache, unittest.TestCase):
+    if c_functools:
+        module = c_functools
+
+
 class TestLRU:
 
     def test_lru(self):
@@ -1773,8 +1823,7 @@ class TestLRU:
             time.sleep(.01)
             return 3 * x
         def test(i, x):
-            with self.subTest(thread=i):
-                self.assertEqual(f(x), 3 * x, i)
+            self.assertEqual(f(x), 3 * x, i)
         threads = [threading.Thread(target=test, args=(i, v))
                    for i, v in enumerate([1, 2, 2, 3, 2])]
         with threading_helper.start_threads(threads):
@@ -1878,6 +1927,7 @@ class TestLRU:
             return 1
         self.assertEqual(f.cache_parameters(), {'maxsize': 1000, "typed": True})
 
+    @support.suppress_immortalization()
     def test_lru_cache_weakrefable(self):
         @self.module.lru_cache
         def test_function(x):
@@ -1908,12 +1958,33 @@ class TestLRU:
             self.assertIsNone(ref())
 
     def test_common_signatures(self):
-        def orig(): ...
+        def orig(a, /, b, c=True): ...
         lru = self.module.lru_cache(1)(orig)
 
+        self.assertEqual(str(Signature.from_callable(lru)), '(a, /, b, c=True)')
         self.assertEqual(str(Signature.from_callable(lru.cache_info)), '()')
         self.assertEqual(str(Signature.from_callable(lru.cache_clear)), '()')
 
+    @support.skip_on_s390x
+    @unittest.skipIf(support.is_wasi, "WASI has limited C stack")
+    def test_lru_recursion(self):
+
+        @self.module.lru_cache
+        def fib(n):
+            if n <= 1:
+                return n
+            return fib(n-1) + fib(n-2)
+
+        if not support.Py_DEBUG:
+            depth = support.get_c_recursion_limit()*2//7
+            with support.infinite_recursion():
+                fib(depth)
+        if self.module == c_functools:
+            fib.cache_clear()
+            with support.infinite_recursion():
+                with self.assertRaises(RecursionError):
+                    fib(10000)
+
 
 @py_functools.lru_cache()
 def py_cached_func(x, y):
@@ -2524,6 +2595,74 @@ class TestSingleDispatch(unittest.TestCase):
         self.assertTrue(A.t(''))
         self.assertEqual(A.t(0.0), 0.0)
 
+    def test_slotted_class(self):
+        class Slot:
+            __slots__ = ('a', 'b')
+            @functools.singledispatchmethod
+            def go(self, item, arg):
+                pass
+
+            @go.register
+            def _(self, item: int, arg):
+                return item + arg
+
+        s = Slot()
+        self.assertEqual(s.go(1, 1), 2)
+
+    def test_classmethod_slotted_class(self):
+        class Slot:
+            __slots__ = ('a', 'b')
+            @functools.singledispatchmethod
+            @classmethod
+            def go(cls, item, arg):
+                pass
+
+            @go.register
+            @classmethod
+            def _(cls, item: int, arg):
+                return item + arg
+
+        s = Slot()
+        self.assertEqual(s.go(1, 1), 2)
+        self.assertEqual(Slot.go(1, 1), 2)
+
+    def test_staticmethod_slotted_class(self):
+        class A:
+            __slots__ = ['a']
+            @functools.singledispatchmethod
+            @staticmethod
+            def t(arg):
+                return arg
+            @t.register(int)
+            @staticmethod
+            def _(arg):
+                return isinstance(arg, int)
+            @t.register(str)
+            @staticmethod
+            def _(arg):
+                return isinstance(arg, str)
+        a = A()
+
+        self.assertTrue(A.t(0))
+        self.assertTrue(A.t(''))
+        self.assertEqual(A.t(0.0), 0.0)
+        self.assertTrue(a.t(0))
+        self.assertTrue(a.t(''))
+        self.assertEqual(a.t(0.0), 0.0)
+
+    def test_assignment_behavior(self):
+        # see gh-106448
+        class A:
+            @functools.singledispatchmethod
+            def t(arg):
+                return arg
+
+        a = A()
+        a.t.foo = 'bar'
+        a2 = A()
+        with self.assertRaises(AttributeError):
+            a2.t.foo
+
     def test_classmethod_register(self):
         class A:
             def __init__(self, arg):
@@ -2659,6 +2798,7 @@ class TestSingleDispatch(unittest.TestCase):
                 """My function docstring"""
                 return str(arg)
 
+        prefix = A.__qualname__ + '.'
         for meth in (
             A.func,
             A().func,
@@ -2668,7 +2808,11 @@ class TestSingleDispatch(unittest.TestCase):
             A().static_func
         ):
             with self.subTest(meth=meth):
-                self.assertEqual(meth.__doc__, 'My function docstring')
+                self.assertEqual(meth.__qualname__, prefix + meth.__name__)
+                self.assertEqual(meth.__doc__,
+                                 ('My function docstring'
+                                  if support.HAVE_PY_DOCSTRINGS
+                                  else None))
                 self.assertEqual(meth.__annotations__['arg'], int)
 
         self.assertEqual(A.func.__name__, 'func')
@@ -2757,7 +2901,10 @@ class TestSingleDispatch(unittest.TestCase):
             WithSingleDispatch().decorated_classmethod
         ):
             with self.subTest(meth=meth):
-                self.assertEqual(meth.__doc__, 'My function docstring')
+                self.assertEqual(meth.__doc__,
+                                 ('My function docstring'
+                                  if support.HAVE_PY_DOCSTRINGS
+                                  else None))
                 self.assertEqual(meth.__annotations__['arg'], int)
 
         self.assertEqual(
@@ -2829,11 +2976,26 @@ class TestSingleDispatch(unittest.TestCase):
 
     def test_invalid_positional_argument(self):
         @functools.singledispatch
-        def f(*args):
+        def f(*args, **kwargs):
             pass
         msg = 'f requires at least 1 positional argument'
         with self.assertRaisesRegex(TypeError, msg):
             f()
+        msg = 'f requires at least 1 positional argument'
+        with self.assertRaisesRegex(TypeError, msg):
+            f(a=1)
+
+    def test_invalid_positional_argument_singledispatchmethod(self):
+        class A:
+            @functools.singledispatchmethod
+            def t(self, *args, **kwargs):
+                pass
+        msg = 't requires at least 1 positional argument'
+        with self.assertRaisesRegex(TypeError, msg):
+            A().t()
+        msg = 't requires at least 1 positional argument'
+        with self.assertRaisesRegex(TypeError, msg):
+            A().t(a=1)
 
     def test_union(self):
         @functools.singledispatch
@@ -2957,6 +3119,115 @@ class TestSingleDispatch(unittest.TestCase):
         self.assertEqual(f(""), "default")
         self.assertEqual(f(b""), "default")
 
+    def test_method_equal_instances(self):
+        # gh-127750: Reference to self was cached
+        class A:
+            def __eq__(self, other):
+                return True
+            def __hash__(self):
+                return 1
+            @functools.singledispatchmethod
+            def t(self, arg):
+                return self
+
+        a = A()
+        b = A()
+        self.assertIs(a.t(1), a)
+        self.assertIs(b.t(2), b)
+
+    def test_method_bad_hash(self):
+        class A:
+            def __eq__(self, other):
+                raise AssertionError
+            def __hash__(self):
+                raise AssertionError
+            @functools.singledispatchmethod
+            def t(self, arg):
+                pass
+
+        # Should not raise
+        A().t(1)
+        hash(A().t)
+        A().t == A().t
+
+    def test_method_no_reference_loops(self):
+        # gh-127750: Created a strong reference to self
+        class A:
+            @functools.singledispatchmethod
+            def t(self, arg):
+                return weakref.ref(self)
+
+        a = A()
+        r = a.t(1)
+        self.assertIsNotNone(r())
+        del a  # delete a after a.t
+        if not support.check_impl_detail(cpython=True):
+            support.gc_collect()
+        self.assertIsNone(r())
+
+        a = A()
+        t = a.t
+        del a # delete a before a.t
+        support.gc_collect()
+        r = t(1)
+        self.assertIsNotNone(r())
+        del t
+        if not support.check_impl_detail(cpython=True):
+            support.gc_collect()
+        self.assertIsNone(r())
+
+    def test_signatures(self):
+        @functools.singledispatch
+        def func(item, arg: int) -> str:
+            return str(item)
+        @func.register
+        def _(item: int, arg: bytes) -> str:
+            return str(item)
+
+        self.assertEqual(str(Signature.from_callable(func)),
+                         '(item, arg: int) -> str')
+
+    def test_method_signatures(self):
+        class A:
+            def m(self, item, arg: int) -> str:
+                return str(item)
+            @classmethod
+            def cm(cls, item, arg: int) -> str:
+                return str(item)
+            @functools.singledispatchmethod
+            def func(self, item, arg: int) -> str:
+                return str(item)
+            @func.register
+            def _(self, item, arg: bytes) -> str:
+                return str(item)
+
+            @functools.singledispatchmethod
+            @classmethod
+            def cls_func(cls, item, arg: int) -> str:
+                return str(arg)
+            @func.register
+            @classmethod
+            def _(cls, item, arg: bytes) -> str:
+                return str(item)
+
+            @functools.singledispatchmethod
+            @staticmethod
+            def static_func(item, arg: int) -> str:
+                return str(arg)
+            @func.register
+            @staticmethod
+            def _(item, arg: bytes) -> str:
+                return str(item)
+
+        self.assertEqual(str(Signature.from_callable(A.func)),
+                         '(self, item, arg: int) -> str')
+        self.assertEqual(str(Signature.from_callable(A().func)),
+                         '(self, item, arg: int) -> str')
+        self.assertEqual(str(Signature.from_callable(A.cls_func)),
+                         '(cls, item, arg: int) -> str')
+        self.assertEqual(str(Signature.from_callable(A.static_func)),
+                         '(item, arg: int) -> str')
+
 
 class CachedCostItem:
     _cost = 1
@@ -3007,8 +3278,7 @@ class TestCachedProperty(unittest.TestCase):
         self.assertEqual(item.get_cost(), 4)
         self.assertEqual(item.cached_cost, 3)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_object_with_slots(self):
         item = CachedCostItemWithSlots()
         with self.assertRaisesRegex(
@@ -3032,8 +3302,7 @@ class TestCachedProperty(unittest.TestCase):
         ):
             MyClass.prop
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
+    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_reuse_different_names(self):
         """Disallow this case because decorated function a would not be cached."""
         with self.assertRaises(TypeError) as ctx:
@@ -3089,7 +3358,13 @@ class TestCachedProperty(unittest.TestCase):
         self.assertIsInstance(CachedCostItem.cost, py_functools.cached_property)
 
     def test_doc(self):
-        self.assertEqual(CachedCostItem.cost.__doc__, "The cost of the item.")
+        self.assertEqual(CachedCostItem.cost.__doc__,
+                         ("The cost of the item."
+                          if support.HAVE_PY_DOCSTRINGS
+                          else None))
+
+    def test_module(self):
+        self.assertEqual(CachedCostItem.cost.__module__, CachedCostItem.__module__)
 
     def test_subclass_with___set__(self):
         """Caching still works for a subclass defining __set__."""