diff options
| -rw-r--r-- | Lib/inspect.py | 11 | ||||
| -rw-r--r-- | Lib/test/test_inspect.py | 14 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 28 insertions, 0 deletions
diff --git a/Lib/inspect.py b/Lib/inspect.py index 9436e35..2211b8d 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -1561,6 +1561,17 @@ def signature(obj): init = _get_user_defined_method(obj, '__init__') if init is not None: sig = signature(init) + + if sig is None: + if type in obj.__mro__: + # 'obj' is a metaclass without user-defined __init__ + # or __new__. Return a signature of 'type' builtin. + return signature(type) + else: + # We have a class (not metaclass), but no user-defined + # __init__ or __new__ for it + return signature(object) + elif not isinstance(obj, _NonUserDefinedCallables): # An object with __call__ # We also check that the 'obj' is not an instance of diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py index f5f18f0..a6b4c7a 100644 --- a/Lib/test/test_inspect.py +++ b/Lib/test/test_inspect.py @@ -2045,6 +2045,20 @@ class TestSignatureObject(unittest.TestCase): ('bar', 2, ..., "keyword_only")), ...)) + # Test classes without user-defined __init__ or __new__ + class C: pass + self.assertEqual(str(inspect.signature(C)), '()') + class D(C): pass + self.assertEqual(str(inspect.signature(D)), '()') + + # Test meta-classes without user-defined __init__ or __new__ + class C(type): pass + self.assertEqual(str(inspect.signature(C)), + '(object_or_name, bases, dict)') + class D(C): pass + self.assertEqual(str(inspect.signature(D)), + '(object_or_name, bases, dict)') + def test_signature_on_callable_objects(self): class Foo: def __call__(self, a): @@ -13,6 +13,9 @@ Core and Builtins Library ------- +- Issue #20308: inspect.signature now works on classes without user-defined + __init__ or __new__ methods. + What's New in Python 3.4.0 Beta 3? ================================== |