From 2d3187bf205ae826bab3d5cf67c0c673e8af2a88 Mon Sep 17 00:00:00 2001 From: Alex Waygood Date: Tue, 25 Jun 2024 16:53:18 +0100 Subject: [PATCH] gh-114053: Fix another edge case involving `get_type_hints`, PEP 695 and PEP 563 (#120272) --- Lib/test/test_typing.py | 66 +++++++++++++++++-- Lib/test/typinganndata/ann_module695.py | 50 ++++++++++++++ Lib/typing.py | 23 +++++-- ...-06-08-15-46-35.gh-issue-114053.Ub2XgJ.rst | 4 ++ 4 files changed, 132 insertions(+), 11 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2024-06-08-15-46-35.gh-issue-114053.Ub2XgJ.rst diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index 9800b3b6a7d..a931da55908 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -4858,20 +4858,30 @@ class GenericTests(BaseTestCase): {'x': list[list[ForwardRef('X')]]} ) - def test_pep695_generic_with_future_annotations(self): + def test_pep695_generic_class_with_future_annotations(self): + original_globals = dict(ann_module695.__dict__) + hints_for_A = get_type_hints(ann_module695.A) A_type_params = ann_module695.A.__type_params__ self.assertIs(hints_for_A["x"], A_type_params[0]) self.assertEqual(hints_for_A["y"].__args__[0], Unpack[A_type_params[1]]) self.assertIs(hints_for_A["z"].__args__[0], A_type_params[2]) + # should not have changed as a result of the get_type_hints() calls! + self.assertEqual(ann_module695.__dict__, original_globals) + + def test_pep695_generic_class_with_future_annotations_and_local_shadowing(self): hints_for_B = get_type_hints(ann_module695.B) - self.assertEqual(hints_for_B.keys(), {"x", "y", "z"}) + self.assertEqual(hints_for_B, {"x": int, "y": str, "z": bytes}) + + def test_pep695_generic_class_with_future_annotations_name_clash_with_global_vars(self): + hints_for_C = get_type_hints(ann_module695.C) self.assertEqual( - set(hints_for_B.values()) ^ set(ann_module695.B.__type_params__), - set() + set(hints_for_C.values()), + set(ann_module695.C.__type_params__) ) + def test_pep_695_generic_function_with_future_annotations(self): hints_for_generic_function = get_type_hints(ann_module695.generic_function) func_t_params = ann_module695.generic_function.__type_params__ self.assertEqual( @@ -4882,6 +4892,54 @@ class GenericTests(BaseTestCase): self.assertIs(hints_for_generic_function["z"].__origin__, func_t_params[2]) self.assertIs(hints_for_generic_function["zz"].__origin__, func_t_params[2]) + def test_pep_695_generic_function_with_future_annotations_name_clash_with_global_vars(self): + self.assertEqual( + set(get_type_hints(ann_module695.generic_function_2).values()), + set(ann_module695.generic_function_2.__type_params__) + ) + + def test_pep_695_generic_method_with_future_annotations(self): + hints_for_generic_method = get_type_hints(ann_module695.D.generic_method) + params = { + param.__name__: param + for param in ann_module695.D.generic_method.__type_params__ + } + self.assertEqual( + hints_for_generic_method, + {"x": params["Foo"], "y": params["Bar"], "return": types.NoneType} + ) + + def test_pep_695_generic_method_with_future_annotations_name_clash_with_global_vars(self): + self.assertEqual( + set(get_type_hints(ann_module695.D.generic_method_2).values()), + set(ann_module695.D.generic_method_2.__type_params__) + ) + + def test_pep_695_generics_with_future_annotations_nested_in_function(self): + results = ann_module695.nested() + + self.assertEqual( + set(results.hints_for_E.values()), + set(results.E.__type_params__) + ) + self.assertEqual( + set(results.hints_for_E_meth.values()), + set(results.E.generic_method.__type_params__) + ) + self.assertNotEqual( + set(results.hints_for_E_meth.values()), + set(results.E.__type_params__) + ) + self.assertEqual( + set(results.hints_for_E_meth.values()).intersection(results.E.__type_params__), + set() + ) + + self.assertEqual( + set(results.hints_for_generic_func.values()), + set(results.generic_func.__type_params__) + ) + def test_extended_generic_rules_subclassing(self): class T1(Tuple[T, KT]): ... class T2(Tuple[T, ...]): ... diff --git a/Lib/test/typinganndata/ann_module695.py b/Lib/test/typinganndata/ann_module695.py index 2ede9fe3825..b6f3b06bd50 100644 --- a/Lib/test/typinganndata/ann_module695.py +++ b/Lib/test/typinganndata/ann_module695.py @@ -17,6 +17,56 @@ class B[T, *Ts, **P]: z: P +Eggs = int +Spam = str + + +class C[Eggs, **Spam]: + x: Eggs + y: Spam + + def generic_function[T, *Ts, **P]( x: T, *y: *Ts, z: P.args, zz: P.kwargs ) -> None: ... + + +def generic_function_2[Eggs, **Spam](x: Eggs, y: Spam): pass + + +class D: + Foo = int + Bar = str + + def generic_method[Foo, **Bar]( + self, x: Foo, y: Bar + ) -> None: ... + + def generic_method_2[Eggs, **Spam](self, x: Eggs, y: Spam): pass + + +def nested(): + from types import SimpleNamespace + from typing import get_type_hints + + Eggs = bytes + Spam = memoryview + + + class E[Eggs, **Spam]: + x: Eggs + y: Spam + + def generic_method[Eggs, **Spam](self, x: Eggs, y: Spam): pass + + + def generic_function[Eggs, **Spam](x: Eggs, y: Spam): pass + + + return SimpleNamespace( + E=E, + hints_for_E=get_type_hints(E), + hints_for_E_meth=get_type_hints(E.generic_method), + generic_func=generic_function, + hints_for_generic_func=get_type_hints(generic_function) + ) diff --git a/Lib/typing.py b/Lib/typing.py index 7a9149d3f3c..bc17d136082 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1060,15 +1060,24 @@ class ForwardRef(_Final, _root=True): globalns = getattr( sys.modules.get(self.__forward_module__, None), '__dict__', globalns ) + + # type parameters require some special handling, + # as they exist in their own scope + # but `eval()` does not have a dedicated parameter for that scope. + # For classes, names in type parameter scopes should override + # names in the global scope (which here are called `localns`!), + # but should in turn be overridden by names in the class scope + # (which here are called `globalns`!) if type_params: - # "Inject" type parameters into the local namespace - # (unless they are shadowed by assignments *in* the local namespace), - # as a way of emulating annotation scopes when calling `eval()` - locals_to_pass = {param.__name__: param for param in type_params} | localns - else: - locals_to_pass = localns + globalns, localns = dict(globalns), dict(localns) + for param in type_params: + param_name = param.__name__ + if not self.__forward_is_class__ or param_name not in globalns: + globalns[param_name] = param + localns.pop(param_name, None) + type_ = _type_check( - eval(self.__forward_code__, globalns, locals_to_pass), + eval(self.__forward_code__, globalns, localns), "Forward references must evaluate to types.", is_argument=self.__forward_is_argument__, allow_special_forms=self.__forward_is_class__, diff --git a/Misc/NEWS.d/next/Library/2024-06-08-15-46-35.gh-issue-114053.Ub2XgJ.rst b/Misc/NEWS.d/next/Library/2024-06-08-15-46-35.gh-issue-114053.Ub2XgJ.rst new file mode 100644 index 00000000000..8aea591da52 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-06-08-15-46-35.gh-issue-114053.Ub2XgJ.rst @@ -0,0 +1,4 @@ +Fix edge-case bug where :func:`typing.get_type_hints` would produce +incorrect results if type parameters in a class scope were overridden by +assignments in a class scope and ``from __future__ import annotations`` +semantics were enabled. Patch by Alex Waygood.