https://github.com/python/cpython/commit/6d6b0c50be370bce5ad65d7a312cd3cedf8139ca commit: 6d6b0c50be370bce5ad65d7a312cd3cedf8139ca branch: 3.14 author: Miss Islington (bot) <[email protected]> committer: JelleZijlstra <[email protected]> date: 2026-06-21T22:35:40Z summary:
[3.14] gh-151665: Fix inspect.signature() on type alias and type parameter evaluators (GH-151787) (#151880) [3.15] gh-151665: Fix inspect.signature() on type alias and type parameter evaluators (GH-151787) (cherry picked from commit 453714a2dc0d16e6e6b8cff70801dfc1284bf74d) Co-authored-by: Timofei <[email protected]> files: A Misc/NEWS.d/next/Library/2026-06-20-14-47-55.gh-issue-151665.82fmzx.rst M Lib/inspect.py M Lib/test/test_type_params.py diff --git a/Lib/inspect.py b/Lib/inspect.py index d3e406cae7d228..f3020bbaa0f196 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -2712,6 +2712,10 @@ def __init__(self, name, kind, *, default=_empty, annotation=_empty): raise ValueError(msg) self._kind = _POSITIONAL_ONLY name = 'implicit{}'.format(name[1:]) + elif name == '.format': + # gh-151665: Hidden parameter of compiler-generated annotation and type + # alias/typevar evaluators. Show it as "format". + name = 'format' # It's possible for C functions to have a positional-only parameter # where the name is a keyword, so for compatibility we'll allow it. diff --git a/Lib/test/test_type_params.py b/Lib/test/test_type_params.py index 84c1b954136736..27660379ec43a3 100644 --- a/Lib/test/test_type_params.py +++ b/Lib/test/test_type_params.py @@ -1,4 +1,5 @@ import annotationlib +import inspect import textwrap import types import unittest @@ -1446,6 +1447,30 @@ def f[T: int = int, **P = int, *Ts = int](): pass self.assertIs(annotationlib.call_evaluate_function(case, annotationlib.Format.FORWARDREF), int) self.assertEqual(annotationlib.call_evaluate_function(case, annotationlib.Format.STRING), 'int') + def test_signature(self): + # gh-151665: the ".format" parameter of compiler-generated evaluators + # used to break inspect.signature(). It should show up as "format". + type Alias = int + def f[T: int = int, **P = int, *Ts = int](): pass + T, P, Ts = f.__type_params__ + def g[T: (int, str)](): pass + T3, = g.__type_params__ + cases = [ + Alias.evaluate_value, + T.evaluate_bound, + T.evaluate_default, + P.evaluate_default, + Ts.evaluate_default, + T3.evaluate_constraints, + ] + for case in cases: + with self.subTest(case=case): + sig = inspect.signature(case) + self.assertEqual(str(sig), '(format=1, /)') + param, = sig.parameters.values() + self.assertEqual(param.name, 'format') + self.assertIs(param.kind, inspect.Parameter.POSITIONAL_ONLY) + def test_constraints(self): def f[T: (int, str)](): pass T, = f.__type_params__ diff --git a/Misc/NEWS.d/next/Library/2026-06-20-14-47-55.gh-issue-151665.82fmzx.rst b/Misc/NEWS.d/next/Library/2026-06-20-14-47-55.gh-issue-151665.82fmzx.rst new file mode 100644 index 00000000000000..d08a1220cbe5ef --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-06-20-14-47-55.gh-issue-151665.82fmzx.rst @@ -0,0 +1,2 @@ +:func:`inspect.signature` now works on the lazy evaluators of type aliases +and type parameters instead of raising :exc:`ValueError`. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
