gh-137969: Fix evaluation of ref.evaluate(format=Format.FORWARDREF) objects

Lib/annotationlib.py

@@ -159,19 +159,21 @@ def evaluate(
             type_params = getattr(owner, "__type_params__", None)
 
         # Type parameters exist in their own scope, which is logically
-        # between the locals and the globals. We simulate this by adding
-        # them to the globals.
+        # between the locals and the globals.
+        type_param_scope = {}
         if type_params is not None:
-            globals = dict(globals)
             for param in type_params:
-                globals[param.__name__] = param
+                type_param_scope[param.__name__] = param
+
         if self.__extra_names__:
             locals = {**locals, **self.__extra_names__}
 
         arg = self.__forward_arg__
         if arg.isidentifier() and not keyword.iskeyword(arg):
             if arg in locals:
                 return locals[arg]
+            elif arg in type_param_scope:
+                return type_param_scope[arg]
             elif arg in globals:
                 return globals[arg]
             elif hasattr(builtins, arg):
@@ -183,12 +185,12 @@ def evaluate(
         else:
             code = self.__forward_code__
             try:
-                return eval(code, globals=globals, locals=locals)
+                return eval(code, globals=globals, locals={**type_param_scope, **locals})
             except Exception:
                 if not is_forwardref_format:
                     raise
             new_locals = _StringifierDict(
-                {**builtins.__dict__, **locals},
+                {**type_param_scope, **builtins.__dict__, **locals},
                 globals=globals,
                 owner=owner,
                 is_class=self.__forward_is_class__,

Lib/test/test_annotationlib.py

@@ -1,30 +1,25 @@
 """Tests for the annotations module."""
 
-import textwrap
-import annotationlib
 import builtins
 import collections
 import functools
 import itertools
 import pickle
-from string.templatelib import Template
+import textwrap
 import typing
 import unittest
-from annotationlib import (
-    Format,
-    ForwardRef,
-    get_annotations,
-    annotations_to_string,
-    type_repr,
-)
-from typing import Unpack, get_type_hints, List, Union
-
+from string.templatelib import Template
 from test import support
 from test.support import import_helper
-from test.test_inspect import inspect_stock_annotations
-from test.test_inspect import inspect_stringized_annotations
-from test.test_inspect import inspect_stringized_annotations_2
-from test.test_inspect import inspect_stringized_annotations_pep695
+from test.test_inspect import (inspect_stock_annotations,
+                               inspect_stringized_annotations,
+                               inspect_stringized_annotations_2,
+                               inspect_stringized_annotations_pep695)
+from typing import List, Union, Unpack, get_type_hints
+
+import annotationlib
+from annotationlib import (Format, ForwardRef, annotations_to_string,
+                           get_annotations, type_repr)
 
 
 def times_three(fn):
@@ -1683,6 +1678,28 @@ def test_fwdref_invalid_syntax(self):
         with self.assertRaises(SyntaxError):
             fr.evaluate()
 
+    def test_re_evaluate(self):
+        class C:
+            x: alias
+
+        evaluated = get_annotations(C, format=Format.FORWARDREF)["x"].evaluate(format=Format.FORWARDREF)
+        alias = int
+        self.assertIs(evaluated.evaluate(), int)
+
+        del alias
+        evaluated = get_annotations(C, format=Format.FORWARDREF)["x"].evaluate(format=Format.FORWARDREF)
+        with self.assertRaises(NameError):
+            evaluated.evaluate()
+
+        class C:
+            x: alias2
+
+        evaluated = get_annotations(C, format=Format.FORWARDREF)["x"].evaluate(format=Format.FORWARDREF)
+        global alias2
+        alias2 = str
+        self.assertIs(evaluated.evaluate(), str)
+
+
 
 class TestAnnotationLib(unittest.TestCase):
     def test__all__(self):

Misc/NEWS.d/next/Library/2025-08-22-23-50-38.gh-issue-137969.Fkvis3.rst

@@ -0,0 +1,2 @@
+Fix :meth:`annotationlib.ForwardRef.evaluate` returning :class:`annotationlib.ForwardRef`
+objects which do not update in new contexts.