mirror of https://github.com/python/cpython
gh-101293: Fix support of custom callables and types in inspect.Signature.from_callable() (GH-115530)
Support callables with the __call__() method and types with __new__() and __init__() methods set to class methods, static methods, bound methods, partial functions, and other types of methods and descriptors. Add tests for numerous types of callables and descriptors.
This commit is contained in:
Serhiy Storchaka
GitHub
parent
8ab6c2775c
commit
59167c962e
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@ -2039,14 +2039,16 @@ def _signature_get_user_defined_method(cls, method_name):
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named ``method_name`` and returns it only if it is a
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pure python function.
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"""
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try:
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meth = getattr(cls, method_name)
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except AttributeError:
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return
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if method_name == '__new__':
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meth = getattr(cls, method_name, None)
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else:
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if not isinstance(meth, _NonUserDefinedCallables):
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meth = getattr_static(cls, method_name, None)
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if meth is None or isinstance(meth, _NonUserDefinedCallables):
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# Once '__signature__' will be added to 'C'-level
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# callables, this check won't be necessary
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return None
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if method_name != '__new__':
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meth = _descriptor_get(meth, cls)
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return meth
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@ -2492,6 +2494,15 @@ def _signature_from_function(cls, func, skip_bound_arg=True,
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__validate_parameters__=is_duck_function)
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def _descriptor_get(descriptor, obj):
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if isclass(descriptor):
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return descriptor
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get = getattr(type(descriptor), '__get__', _sentinel)
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if get is _sentinel:
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return descriptor
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return get(descriptor, obj, type(obj))
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def _signature_from_callable(obj, *,
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follow_wrapper_chains=True,
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skip_bound_arg=True,
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@ -2600,7 +2611,6 @@ def _signature_from_callable(obj, *,
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wrapped_sig = _get_signature_of(obj.func)
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return _signature_get_partial(wrapped_sig, obj)
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sig = None
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if isinstance(obj, type):
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# obj is a class or a metaclass
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@ -2608,9 +2618,8 @@ def _signature_from_callable(obj, *,
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# in its metaclass
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call = _signature_get_user_defined_method(type(obj), '__call__')
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if call is not None:
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sig = _get_signature_of(call)
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else:
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factory_method = None
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return _get_signature_of(call)
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new = _signature_get_user_defined_method(obj, '__new__')
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init = _signature_get_user_defined_method(obj, '__init__')
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@ -2619,17 +2628,14 @@ def _signature_from_callable(obj, *,
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for base in obj.__mro__:
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# Now we check if the 'obj' class has an own '__new__' method
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if new is not None and '__new__' in base.__dict__:
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factory_method = new
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break
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sig = _get_signature_of(new)
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if skip_bound_arg:
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sig = _signature_bound_method(sig)
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return sig
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# or an own '__init__' method
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elif init is not None and '__init__' in base.__dict__:
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factory_method = init
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break
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return _get_signature_of(init)
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if factory_method is not None:
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sig = _get_signature_of(factory_method)
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if sig is None:
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# At this point we know, that `obj` is a class, with no user-
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# defined '__init__', '__new__', or class-level '__call__'
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@ -2665,31 +2671,12 @@ def _signature_from_callable(obj, *,
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raise ValueError(
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'no signature found for builtin type {!r}'.format(obj))
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elif not isinstance(obj, _NonUserDefinedCallables):
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# An object with __call__
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# We also check that the 'obj' is not an instance of
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# types.WrapperDescriptorType or types.MethodWrapperType to avoid
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# infinite recursion (and even potential segfault)
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call = _signature_get_user_defined_method(type(obj), '__call__')
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if call is not None:
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try:
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sig = _get_signature_of(call)
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except ValueError as ex:
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msg = 'no signature found for {!r}'.format(obj)
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raise ValueError(msg) from ex
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if sig is not None:
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# For classes and objects we skip the first parameter of their
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# __call__, __new__, or __init__ methods
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if skip_bound_arg:
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return _signature_bound_method(sig)
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else:
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return sig
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if isinstance(obj, types.BuiltinFunctionType):
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# Raise a nicer error message for builtins
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msg = 'no signature found for builtin function {!r}'.format(obj)
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raise ValueError(msg)
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# An object with __call__
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call = getattr_static(type(obj), '__call__', None)
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if call is not None:
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call = _descriptor_get(call, obj)
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return _get_signature_of(call)
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raise ValueError('callable {!r} is not supported by signature'.format(obj))
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@ -2928,9 +2928,12 @@ class TestSignatureObject(unittest.TestCase):
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# This doesn't work now.
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# (We don't have a valid signature for "type" in 3.4)
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with self.assertRaisesRegex(ValueError, "no signature found"):
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class ThisWorksNow:
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__call__ = type
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# TODO: Support type.
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self.assertEqual(ThisWorksNow()(1), int)
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self.assertEqual(ThisWorksNow()('A', (), {}).__name__, 'A')
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with self.assertRaisesRegex(ValueError, "no signature found"):
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test_callable(ThisWorksNow())
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# Regression test for issue #20786
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@ -3521,6 +3524,98 @@ class TestSignatureObject(unittest.TestCase):
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('classmethod'):
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class CM(type):
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@classmethod
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def __call__(cls, a):
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return a
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('staticmethod'):
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class CM(type):
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@staticmethod
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def __call__(a):
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return a
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('MethodType'):
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class A:
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def call(self, a):
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return a
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class CM(type):
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__call__ = A().call
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partial'):
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class CM(type):
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__call__ = functools.partial(lambda x, a: (x, a), 2)
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(1), (2, 1))
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partialmethod'):
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class CM(type):
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__call__ = functools.partialmethod(lambda self, x, a: (x, a), 2)
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(1), (2, 1))
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('BuiltinMethodType'):
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class CM(type):
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__call__ = ':'.join
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(['a', 'bc']), 'a:bc')
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# BUG: Returns '<Signature (b)>'
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with self.assertRaises(AssertionError):
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self.assertEqual(self.signature(C), self.signature(''.join))
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with self.subTest('MethodWrapperType'):
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class CM(type):
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__call__ = (2).__pow__
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class C(metaclass=CM):
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def __init__(self, b):
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pass
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self.assertEqual(C(3), 8)
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self.assertEqual(C(3, 7), 1)
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# BUG: Returns '<Signature (b)>'
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with self.assertRaises(AssertionError):
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self.assertEqual(self.signature(C), self.signature((0).__pow__))
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class CM(type):
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def __new__(mcls, name, bases, dct, *, foo=1):
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return super().__new__(mcls, name, bases, dct)
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@ -3582,6 +3677,169 @@ class TestSignatureObject(unittest.TestCase):
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('bar', 2, ..., "keyword_only")),
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...))
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def test_signature_on_class_with_init(self):
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class C:
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def __init__(self, b):
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pass
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C(1) # does not raise
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self.assertEqual(self.signature(C),
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((('b', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('classmethod'):
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class C:
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@classmethod
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def __init__(cls, b):
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pass
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C(1) # does not raise
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self.assertEqual(self.signature(C),
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((('b', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('staticmethod'):
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class C:
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@staticmethod
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def __init__(b):
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pass
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C(1) # does not raise
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self.assertEqual(self.signature(C),
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((('b', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('MethodType'):
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class A:
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def call(self, a):
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pass
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class C:
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__init__ = A().call
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C(1) # does not raise
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partial'):
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class C:
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__init__ = functools.partial(lambda x, a: None, 2)
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C(1) # does not raise
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partialmethod'):
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class C:
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def _init(self, x, a):
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self.a = (x, a)
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__init__ = functools.partialmethod(_init, 2)
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self.assertEqual(C(1).a, (2, 1))
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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def test_signature_on_class_with_new(self):
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with self.subTest('FunctionType'):
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class C:
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def __new__(cls, a):
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return a
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('classmethod'):
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class C:
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@classmethod
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def __new__(cls, cls2, a):
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return a
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('staticmethod'):
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class C:
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@staticmethod
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def __new__(cls, a):
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return a
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('MethodType'):
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class A:
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def call(self, cls, a):
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return a
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class C:
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__new__ = A().call
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self.assertEqual(C(1), 1)
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partial'):
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class C:
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__new__ = functools.partial(lambda x, cls, a: (x, a), 2)
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self.assertEqual(C(1), (2, 1))
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partialmethod'):
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class C:
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__new__ = functools.partialmethod(lambda cls, x, a: (x, a), 2)
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self.assertEqual(C(1), (2, 1))
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self.assertEqual(self.signature(C),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('BuiltinMethodType'):
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class C:
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__new__ = str.__subclasscheck__
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self.assertEqual(C(), False)
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# TODO: Support BuiltinMethodType
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# self.assertEqual(self.signature(C), ((), ...))
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self.assertRaises(ValueError, self.signature, C)
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with self.subTest('MethodWrapperType'):
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class C:
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__new__ = type.__or__.__get__(int, type)
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self.assertEqual(C(), C | int)
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# TODO: Support MethodWrapperType
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# self.assertEqual(self.signature(C), ((), ...))
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self.assertRaises(ValueError, self.signature, C)
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# TODO: Test ClassMethodDescriptorType
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with self.subTest('MethodDescriptorType'):
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class C:
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__new__ = type.__dict__['__subclasscheck__']
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self.assertEqual(C(C), True)
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self.assertEqual(self.signature(C), self.signature(C.__subclasscheck__))
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with self.subTest('WrapperDescriptorType'):
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class C:
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__new__ = type.__or__
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self.assertEqual(C(int), C | int)
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# TODO: Support WrapperDescriptorType
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# self.assertEqual(self.signature(C), self.signature(C.__or__))
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self.assertRaises(ValueError, self.signature, C)
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def test_signature_on_subclass(self):
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class A:
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def __new__(cls, a=1, *args, **kwargs):
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@ -3635,8 +3893,11 @@ class TestSignatureObject(unittest.TestCase):
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# Test meta-classes without user-defined __init__ or __new__
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class C(type): pass
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class D(C): pass
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self.assertEqual(C('A', (), {}).__name__, 'A')
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# TODO: Support type.
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with self.assertRaisesRegex(ValueError, "callable.*is not supported"):
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self.assertEqual(inspect.signature(C), None)
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self.assertEqual(D('A', (), {}).__name__, 'A')
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with self.assertRaisesRegex(ValueError, "callable.*is not supported"):
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self.assertEqual(inspect.signature(D), None)
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@ -3686,6 +3947,103 @@ class TestSignatureObject(unittest.TestCase):
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('classmethod'):
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class C:
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@classmethod
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def __call__(cls, a):
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pass
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self.assertEqual(self.signature(C()),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('staticmethod'):
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class C:
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@staticmethod
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def __call__(a):
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pass
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self.assertEqual(self.signature(C()),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('MethodType'):
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class A:
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def call(self, a):
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return a
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class C:
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__call__ = A().call
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self.assertEqual(C()(1), 1)
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self.assertEqual(self.signature(C()),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partial'):
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class C:
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__call__ = functools.partial(lambda x, a: (x, a), 2)
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self.assertEqual(C()(1), (2, 1))
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self.assertEqual(self.signature(C()),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('partialmethod'):
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class C:
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__call__ = functools.partialmethod(lambda self, x, a: (x, a), 2)
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self.assertEqual(C()(1), (2, 1))
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self.assertEqual(self.signature(C()),
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((('a', ..., ..., "positional_or_keyword"),),
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...))
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with self.subTest('BuiltinMethodType'):
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class C:
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__call__ = ':'.join
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self.assertEqual(C()(['a', 'bc']), 'a:bc')
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self.assertEqual(self.signature(C()), self.signature(''.join))
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with self.subTest('MethodWrapperType'):
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class C:
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__call__ = (2).__pow__
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self.assertEqual(C()(3), 8)
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self.assertEqual(self.signature(C()), self.signature((0).__pow__))
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with self.subTest('ClassMethodDescriptorType'):
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class C(dict):
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||||
__call__ = dict.__dict__['fromkeys']
|
||||
|
||||
res = C()([1, 2], 3)
|
||||
self.assertEqual(res, {1: 3, 2: 3})
|
||||
self.assertEqual(type(res), C)
|
||||
self.assertEqual(self.signature(C()), self.signature(dict.fromkeys))
|
||||
|
||||
with self.subTest('MethodDescriptorType'):
|
||||
class C(str):
|
||||
__call__ = str.join
|
||||
|
||||
self.assertEqual(C(':')(['a', 'bc']), 'a:bc')
|
||||
self.assertEqual(self.signature(C()), self.signature(''.join))
|
||||
|
||||
with self.subTest('WrapperDescriptorType'):
|
||||
class C(int):
|
||||
__call__ = int.__pow__
|
||||
|
||||
self.assertEqual(C(2)(3), 8)
|
||||
self.assertEqual(self.signature(C()), self.signature((0).__pow__))
|
||||
|
||||
with self.subTest('MemberDescriptorType'):
|
||||
class C:
|
||||
__slots__ = '__call__'
|
||||
c = C()
|
||||
c.__call__ = lambda a: a
|
||||
self.assertEqual(c(1), 1)
|
||||
self.assertEqual(self.signature(c),
|
||||
((('a', ..., ..., "positional_or_keyword"),),
|
||||
...))
|
||||
|
||||
def test_signature_on_wrapper(self):
|
||||
class Wrapper:
|
||||
def __call__(self, b):
|
||||
|
|
|
|||
|
|
@ -0,0 +1,4 @@
|
|||
Support callables with the ``__call__()`` method and types with
|
||||
``__new__()`` and ``__init__()`` methods set to class methods, static
|
||||
methods, bound methods, partial functions, and other types of methods and
|
||||
descriptors in :meth:`inspect.Signature.from_callable`.
|
||||
Loading…
Reference in New Issue