From 8aba6939b468501bafb04cce86b8f05e690c1edc Mon Sep 17 00:00:00 2001 From: Ivy Xu Date: Fri, 3 Jul 2026 16:42:06 +0800 Subject: [PATCH] gh-150641: Fix evaluating forward references in STRING format can 'leak' internal names in `typing` (GH-150648) (cherry picked from commit f75028f7ceebee4cbeb46bf040834e2005d57436) Co-authored-by: Ivy Xu Co-authored-by: Jelle Zijlstra --- Lib/test/test_typing.py | 12 ++++++++++++ Lib/typing.py | 2 +- .../2026-05-31-14-39-25.gh-issue-150641.LLIhd1.rst | 2 ++ 3 files changed, 15 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Library/2026-05-31-14-39-25.gh-issue-150641.LLIhd1.rst diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index 042604ed7c1a423..0c57c83491042df 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -7582,6 +7582,18 @@ def test_with_module(self): typing.evaluate_forward_ref( fwdref_module.fw,) + def test_evaluate_forward_ref_string_format(self): + # Test evaluating forward references in STRING format + # does not 'leak' internal names + # See https://github.com/python/cpython/issues/150641 + + def f(arg: unknown | str | int | list[str] | tuple[int, ...]): ... + + ref = annotationlib.get_annotations(f, format=annotationlib.Format.FORWARDREF)['arg'] + self.assertEqual( + typing.evaluate_forward_ref(ref, format=annotationlib.Format.STRING), + "unknown | str | int | list[str] | tuple[int, ...]", + ) class CollectionsAbcTests(BaseTestCase): diff --git a/Lib/typing.py b/Lib/typing.py index 6011b62cd26944f..8b17cbbae2f6ec6 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1032,7 +1032,7 @@ def evaluate_forward_ref( """ if format == annotationlib.Format.STRING: - return forward_ref.__forward_arg__ + return forward_ref.__resolved_str__ if forward_ref.__forward_arg__ in _recursive_guard: return forward_ref diff --git a/Misc/NEWS.d/next/Library/2026-05-31-14-39-25.gh-issue-150641.LLIhd1.rst b/Misc/NEWS.d/next/Library/2026-05-31-14-39-25.gh-issue-150641.LLIhd1.rst new file mode 100644 index 000000000000000..eba899c96fcd26b --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-05-31-14-39-25.gh-issue-150641.LLIhd1.rst @@ -0,0 +1,2 @@ +Fix bug where :func:`typing.evaluate_forward_ref` with the ``STRING`` format +could leak internal names used by the annotation machinery.