https://github.com/python/cpython/commit/25a12aac4de819745dfc64664ba183a5784... commit: 25a12aac4de819745dfc64664ba183a5784b5a81 branch: 3.9 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: serhiy-storchaka <storchaka@gmail.com> date: 2021-12-26T14:23:23+02:00 summary: [3.9] bpo-46032: Check types in singledispatch's register() at declaration time (GH-30050) (GH-30254) (GH-30255) The registry() method of 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]). (cherry picked from commit 078abb676cf759b1e960f78390b6e80f256f0255) (cherry picked from commit 03c7449fbc7c57f5e0365f234a0b65c1dde763f2) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> files: A Misc/NEWS.d/next/Library/2021-12-11-15-45-07.bpo-46032.HmciLT.rst M Lib/functools.py M Lib/test/test_functools.py diff --git a/Lib/functools.py b/Lib/functools.py index 1a290e1c02461..77e5035ebcc9d 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -739,6 +739,7 @@ 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 @@ -836,6 +837,9 @@ def dispatch(cls): dispatch_cache[cls] = impl return impl + def _is_valid_dispatch_type(cls): + return isinstance(cls, type) and not isinstance(cls, GenericAlias) + def register(cls, func=None): """generic_func.register(cls, func) -> func @@ -843,9 +847,15 @@ def register(cls, func=None): """ nonlocal cache_token - if func is None: - if isinstance(cls, type): + 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." + ) ann = getattr(cls, '__annotations__', {}) if not ann: raise TypeError( @@ -858,11 +868,12 @@ def register(cls, func=None): # 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): + if not _is_valid_dispatch_type(cls): raise TypeError( f"Invalid annotation for {argname!r}. " f"{cls!r} is not a class." ) + registry[cls] = func if cache_token is None and hasattr(cls, '__abstractmethods__'): cache_token = get_cache_token() diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py index b2a7e5a88b422..d7dec3f3d2756 100644 --- a/Lib/test/test_functools.py +++ b/Lib/test/test_functools.py @@ -2560,7 +2560,7 @@ def decorated_classmethod(cls, arg: int) -> str: self.assertEqual(without_single_dispatch_foo, single_dispatch_foo) self.assertEqual(single_dispatch_foo, '5') - + self.assertEqual( WithoutSingleDispatch.decorated_classmethod(5), WithSingleDispatch.decorated_classmethod(5) @@ -2655,6 +2655,74 @@ def f(*args): with self.assertRaisesRegex(TypeError, msg): f() + 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(typing.Union[list[int], str], lambda arg: "typing.Union[types.GenericAlias]") + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.Union[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(typing.Union[list[int], str]) + with self.assertRaisesRegex(TypeError, "Invalid first argument to "): + f.register(typing.Union[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: typing.Union[list[int], str]): + return "types.UnionType(types.GenericAlias)" + with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"): + @f.register + def _(arg: typing.Union[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 0000000000000..97a553d7ba29f --- /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]``).