https://github.com/python/cpython/commit/cb6596c6aa30c8c3213c8746d5590e6e2757a6c1
commit: cb6596c6aa30c8c3213c8746d5590e6e2757a6c1
branch: main
author: Jelle Zijlstra <jelle.zijls...@gmail.com>
committer: JelleZijlstra <jelle.zijls...@gmail.com>
date: 2025-05-09T18:42:53-07:00
summary:
gh-132493: Remove __annotations__ usage in inspect._signature_is_functionlike
(#133415)
This check is potentially problematic because it could force evaluation of
annotations unnecessarily. This doesn't trigger for builtin objects (functions,
classes, or modules) with annotations, but it could trigger for third-party
objects.
The check was not particularly useful anyway, because it succeeds if
``__annotations__``
is a dict or None, so the only thing this did was guard against objects that
have an
``__annotations__`` attribute that is of some other type. That doesn't seem
particularly
useful, so I just removed the check.
files:
A Misc/NEWS.d/next/Library/2025-05-04-17-04-55.gh-issue-132493.huirKi.rst
M Lib/inspect.py
M Lib/test/test_inspect/test_inspect.py
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 52c9bb05b31f37..183e67fabf966e 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -2074,13 +2074,11 @@ def _signature_is_functionlike(obj):
code = getattr(obj, '__code__', None)
defaults = getattr(obj, '__defaults__', _void) # Important to use _void ...
kwdefaults = getattr(obj, '__kwdefaults__', _void) # ... and not None here
- annotations = getattr(obj, '__annotations__', None)
return (isinstance(code, types.CodeType) and
isinstance(name, str) and
(defaults is None or isinstance(defaults, tuple)) and
- (kwdefaults is None or isinstance(kwdefaults, dict)) and
- (isinstance(annotations, (dict)) or annotations is None) )
+ (kwdefaults is None or isinstance(kwdefaults, dict)))
def _signature_strip_non_python_syntax(signature):
diff --git a/Lib/test/test_inspect/test_inspect.py
b/Lib/test/test_inspect/test_inspect.py
index bc1129827079d4..1c325c0d5075a2 100644
--- a/Lib/test/test_inspect/test_inspect.py
+++ b/Lib/test/test_inspect/test_inspect.py
@@ -4997,6 +4997,37 @@ def test_signature_annotation_format(self):
with self.assertRaisesRegex(NameError, "undefined"):
signature_func(ida.f)
+ def test_signature_deferred_annotations(self):
+ def f(x: undef):
+ pass
+
+ class C:
+ x: undef
+
+ def __init__(self, x: undef):
+ self.x = x
+
+ sig = inspect.signature(f, annotation_format=Format.FORWARDREF)
+ self.assertEqual(list(sig.parameters), ['x'])
+ sig = inspect.signature(C, annotation_format=Format.FORWARDREF)
+ self.assertEqual(list(sig.parameters), ['x'])
+
+ class CallableWrapper:
+ def __init__(self, func):
+ self.func = func
+ self.__annotate__ = func.__annotate__
+
+ def __call__(self, *args, **kwargs):
+ return self.func(*args, **kwargs)
+
+ @property
+ def __annotations__(self):
+ return self.__annotate__(Format.VALUE)
+
+ cw = CallableWrapper(f)
+ sig = inspect.signature(cw, annotation_format=Format.FORWARDREF)
+ self.assertEqual(list(sig.parameters), ['args', 'kwargs'])
+
def test_signature_none_annotation(self):
class funclike:
# Has to be callable, and have correct
diff --git
a/Misc/NEWS.d/next/Library/2025-05-04-17-04-55.gh-issue-132493.huirKi.rst
b/Misc/NEWS.d/next/Library/2025-05-04-17-04-55.gh-issue-132493.huirKi.rst
new file mode 100644
index 00000000000000..ad06ee6b7a2757
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-05-04-17-04-55.gh-issue-132493.huirKi.rst
@@ -0,0 +1,2 @@
+Avoid accessing ``__annotations__`` unnecessarily in
+:func:`inspect.signature`.
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