https://github.com/python/cpython/commit/666eeda13d319aa82b151eef3e3c55a48d90a052
commit: 666eeda13d319aa82b151eef3e3c55a48d90a052
branch: main
author: Jelle Zijlstra <jelle.zijls...@gmail.com>
committer: JelleZijlstra <jelle.zijls...@gmail.com>
date: 2025-04-15T10:14:27-07:00
summary:
gh-132493: Support deferred annotations in Protocols (#132494)
files:
A Misc/NEWS.d/next/Library/2025-04-13-21-35-50.gh-issue-132493.5SAQJn.rst
M Lib/test/test_typing.py
M Lib/typing.py
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 9f9e3eb17b9fc9..fc893807837eb9 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -4554,6 +4554,15 @@ class Commentable(Protocol):
)
self.assertIs(type(exc.__cause__), CustomError)
+ def test_deferred_evaluation_of_annotations(self):
+ class DeferredProto(Protocol):
+ x: DoesNotExist
+ self.assertEqual(get_protocol_members(DeferredProto), {"x"})
+ self.assertEqual(
+ annotationlib.get_annotations(DeferredProto,
format=annotationlib.Format.STRING),
+ {'x': 'DoesNotExist'}
+ )
+
class GenericTests(BaseTestCase):
diff --git a/Lib/typing.py b/Lib/typing.py
index e5d14b03a4fc94..08b2ba356fc014 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1801,7 +1801,9 @@ def _get_protocol_attrs(cls):
for base in cls.__mro__[:-1]: # without object
if base.__name__ in {'Protocol', 'Generic'}:
continue
- annotations = getattr(base, '__annotations__', {})
+ annotations = _lazy_annotationlib.get_annotations(
+ base, format=_lazy_annotationlib.Format.FORWARDREF
+ )
for attr in (*base.__dict__, *annotations):
if not attr.startswith('_abc_') and attr not in
EXCLUDED_ATTRIBUTES:
attrs.add(attr)
diff --git
a/Misc/NEWS.d/next/Library/2025-04-13-21-35-50.gh-issue-132493.5SAQJn.rst
b/Misc/NEWS.d/next/Library/2025-04-13-21-35-50.gh-issue-132493.5SAQJn.rst
new file mode 100644
index 00000000000000..bda09e2356d56d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-04-13-21-35-50.gh-issue-132493.5SAQJn.rst
@@ -0,0 +1,2 @@
+Support creation of :class:`typing.Protocol` classes with annotations that
+cannot be resolved at class creation time.
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