diff options
| -rw-r--r-- | Lib/functools.py | 2 | ||||
| -rw-r--r-- | Lib/test/test_functools.py | 18 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 22 insertions, 1 deletions
diff --git a/Lib/functools.py b/Lib/functools.py index 3e93a3d..2c299d7 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -551,7 +551,7 @@ def _c3_merge(sequences): break # reject the current head, it appears later else: break - if not candidate: + if candidate is None: raise RuntimeError("Inconsistent hierarchy") result.append(candidate) # remove the chosen candidate diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py index 36f154a..c0d24d8c 100644 --- a/Lib/test/test_functools.py +++ b/Lib/test/test_functools.py @@ -1328,6 +1328,24 @@ class TestSingleDispatch(unittest.TestCase): many_abcs = [c.Mapping, c.Sized, c.Callable, c.Container, c.Iterable] self.assertEqual(mro(X, abcs=many_abcs), expected) + def test_false_meta(self): + # see issue23572 + class MetaA(type): + def __len__(self): + return 0 + class A(metaclass=MetaA): + pass + class AA(A): + pass + @functools.singledispatch + def fun(a): + return 'base A' + @fun.register(A) + def _(a): + return 'fun A' + aa = AA() + self.assertEqual(fun(aa), 'fun A') + def test_mro_conflicts(self): c = collections @functools.singledispatch @@ -392,6 +392,9 @@ Library - Issue #24298: Fix inspect.signature() to correctly unwrap wrappers around bound methods. +- Issue #23572: Fixed functools.singledispatch on classes with falsy + metaclasses. Patch by Ethan Furman. + IDLE ---- |