Fix ClassVar forward ref inherited from parent class (#9097)

pydantic/_internal/_typing_extra.py

@@ -2,6 +2,7 @@
 from __future__ import annotations as _annotations
 
 import dataclasses
+import re
 import sys
 import types
 import typing
@@ -146,7 +147,10 @@ def is_classvar(ann_type: type[Any]) -> bool:
 
     # this is an ugly workaround for class vars that contain forward references and are therefore themselves
     # forward references, see #3679
-    if ann_type.__class__ == typing.ForwardRef and ann_type.__forward_arg__.startswith('ClassVar['):  # type: ignore
+    if ann_type.__class__ == typing.ForwardRef and re.match(
+        r'(\w+\.)?ClassVar\[',
+        ann_type.__forward_arg__,  # type: ignore
+    ):
         return True
 
     return False

tests/test_main.py

@@ -3163,3 +3163,21 @@ class Model(BaseModel):
             'input': {'not a str or int'},
         },
     ]
+
+
+def test_inherited_class_vars(create_module):
+    @create_module
+    def module():
+        import typing
+
+        from pydantic import BaseModel
+
+        class Base(BaseModel):
+            CONST1: 'typing.ClassVar[str]' = 'a'
+            CONST2: 'ClassVar[str]' = 'b'
+
+    class Child(module.Base):
+        pass
+
+    assert Child.CONST1 == 'a'
+    assert Child.CONST2 == 'b'

tests/test_typing.py

@@ -91,7 +91,11 @@ def test_is_literal_with_typing_literal():
     'ann_type,extepcted',
     (
         (None, False),
+        (ForwardRef('Other[int]'), False),
+        (ForwardRef('Other[ClassVar[int]]'), False),
         (ForwardRef('ClassVar[int]'), True),
+        (ForwardRef('t.ClassVar[int]'), True),
+        (ForwardRef('typing.ClassVar[int]'), True),
         (ClassVar[int], True),
     ),
 )