From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 24 Sep 2024 21:02:18 +0000 (-0700)
Subject: dataclasses: Avoid using private class (#124465)
X-Git-Tag: v3.14.0a1~360
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=950fab46ad3a1960aa289d2d1de55447b88e25d7;p=thirdparty%2FPython%2Fcpython.git

dataclasses: Avoid using private class (#124465)

typing.get_origin() does what we need here, without reaching into
typing internals. This shouldn't change any behavior (so I am going
to skip news), but it sets a good example for other users introspecting
typing objects.
---

diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index ac7d40cf2cac..6255d8980974 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -690,11 +690,8 @@ def _frozen_get_del_attr(cls, fields, func_builder):
 
 
 def _is_classvar(a_type, typing):
-    # This test uses a typing internal class, but it's the best way to
-    # test if this is a ClassVar.
     return (a_type is typing.ClassVar
-            or (type(a_type) is typing._GenericAlias
-                and a_type.__origin__ is typing.ClassVar))
+            or (typing.get_origin(a_type) is typing.ClassVar))
 
 
 def _is_initvar(a_type, dataclasses):