diff options
| -rw-r--r-- | Lib/functools.py | 21 | ||||
| -rw-r--r-- | Lib/test/test_functools.py | 68 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2021-12-11-15-45-07.bpo-46032.HmciLT.rst | 5 |
3 files changed, 89 insertions, 5 deletions
diff --git a/Lib/functools.py b/Lib/functools.py index ccac6f8..91b678c 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -740,6 +740,7 @@ def _compose_mro(cls, types): # Remove entries which are already present in the __mro__ or unrelated. def is_related(typ): return (typ not in bases and hasattr(typ, '__mro__') + and not isinstance(typ, GenericAlias) and issubclass(cls, typ)) types = [n for n in types if is_related(n)] # Remove entries which are strict bases of other entries (they will end up @@ -841,9 +842,13 @@ def singledispatch(func): from typing import get_origin, Union return get_origin(cls) in {Union, types.UnionType} - def _is_valid_union_type(cls): + def _is_valid_dispatch_type(cls): + if isinstance(cls, type) and not isinstance(cls, GenericAlias): + return True from typing import get_args - return _is_union_type(cls) and all(isinstance(arg, type) for arg in get_args(cls)) + return (_is_union_type(cls) and + all(isinstance(arg, type) and not isinstance(arg, GenericAlias) + for arg in get_args(cls))) def register(cls, func=None): """generic_func.register(cls, func) -> func @@ -852,9 +857,15 @@ def singledispatch(func): """ nonlocal cache_token - if func is None: - if isinstance(cls, type) or _is_valid_union_type(cls): + if _is_valid_dispatch_type(cls): + if func is None: return lambda f: register(cls, f) + else: + if func is not None: + raise TypeError( + f"Invalid first argument to `register()`. " + f"{cls!r} is not a class or union type." + ) ann = getattr(cls, '__annotations__', {}) if not ann: raise TypeError( @@ -867,7 +878,7 @@ def singledispatch(func): # only import typing if annotation parsing is necessary from typing import get_type_hints argname, cls = next(iter(get_type_hints(func).items())) - if not isinstance(cls, type) and not _is_valid_union_type(cls): + if not _is_valid_dispatch_type(cls): if _is_union_type(cls): raise TypeError( f"Invalid annotation for {argname!r}. " diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py index 755ac03..70ae8e0 100644 --- a/Lib/test/test_functools.py +++ b/Lib/test/test_functools.py @@ -2722,6 +2722,74 @@ class TestSingleDispatch(unittest.TestCase): self.assertEqual(f(1), "types.UnionType") self.assertEqual(f(1.0), "types.UnionType") + def test_register_genericalias(self): + @functools.singledispatch + def f(arg): + return "default" + + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(list[int], lambda arg: "types.GenericAlias") + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.List[int], lambda arg: "typing.GenericAlias") + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(list[int] | str, lambda arg: "types.UnionTypes(types.GenericAlias)") + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.List[float] | bytes, lambda arg: "typing.Union[typing.GenericAlias]") + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.Any, lambda arg: "typing.Any") + + self.assertEqual(f([1]), "default") + self.assertEqual(f([1.0]), "default") + self.assertEqual(f(""), "default") + self.assertEqual(f(b""), "default") + + def test_register_genericalias_decorator(self): + @functools.singledispatch + def f(arg): + return "default" + + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(list[int]) + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.List[int]) + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(list[int] | str) + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.List[int] | str) + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.Any) + + def test_register_genericalias_annotation(self): + @functools.singledispatch + def f(arg): + return "default" + + with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"): + @f.register + def _(arg: list[int]): + return "types.GenericAlias" + with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"): + @f.register + def _(arg: typing.List[float]): + return "typing.GenericAlias" + with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"): + @f.register + def _(arg: list[int] | str): + return "types.UnionType(types.GenericAlias)" + with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"): + @f.register + def _(arg: typing.List[float] | bytes): + return "typing.Union[typing.GenericAlias]" + with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"): + @f.register + def _(arg: typing.Any): + return "typing.Any" + + self.assertEqual(f([1]), "default") + self.assertEqual(f([1.0]), "default") + self.assertEqual(f(""), "default") + self.assertEqual(f(b""), "default") + class CachedCostItem: _cost = 1 diff --git a/Misc/NEWS.d/next/Library/2021-12-11-15-45-07.bpo-46032.HmciLT.rst b/Misc/NEWS.d/next/Library/2021-12-11-15-45-07.bpo-46032.HmciLT.rst new file mode 100644 index 0000000..97a553d --- /dev/null +++ b/Misc/NEWS.d/next/Library/2021-12-11-15-45-07.bpo-46032.HmciLT.rst @@ -0,0 +1,5 @@ +The ``registry()`` method of :func:`functools.singledispatch` functions +checks now the first argument or the first parameter annotation and raises a +TypeError if it is not supported. Previously unsupported "types" were +ignored (e.g. ``typing.List[int]``) or caused an error at calling time (e.g. +``list[int]``). |