gh-156515: Correctly filter conditional annotations in FORWARDREF and STRING formats

Author: JelleZijlstra

Lib/annotationlib.py

@@ -855,6 +855,11 @@ def _build_closure(annotate, owner, is_class, stringifier_dict, *, allow_evaluat
     cell_dict = {}
     for name, cell in zip(annotate.__code__.co_freevars, annotate.__closure__, strict=True):
         cell_dict[name] = cell
+        # This is an internal name for ensuring we get the correct annotations,
+        # so do not replace the original cell.
+        if name == "__conditional_annotations__":
+            new_closure.append(cell)
+            continue
         new_cell = None
         if allow_evaluation:
             try:

Lib/test/test_annotationlib.py

@@ -1206,6 +1206,22 @@ def __call__(self):
                 with self.subTest(format=format, obj=obj):
                     self.assertEqual(get_annotations(obj, format=format), {})
 
+    def test_conditional_annotations(self):
+        class ConditionalAnnotations:
+            x: int
+            if False:
+                y: str
+
+        self.assertEqual(get_annotations(ConditionalAnnotations), {"x": int})
+        self.assertEqual(
+            get_annotations(ConditionalAnnotations, format=Format.FORWARDREF),
+            {"x": int},
+        )
+        self.assertEqual(
+            get_annotations(ConditionalAnnotations, format=Format.STRING),
+            {"x": "int"},
+        )
+
     def test_pep695_generic_class_with_future_annotations(self):
         ann_module695 = inspect_stringized_annotations_pep695
         A_annotations = get_annotations(ann_module695.A, eval_str=True)

Misc/NEWS.d/next/Library/2026-08-28-06-22-30.gh-issue-156515.f-GVyF.rst

@@ -0,0 +1,2 @@
+Fix bug where :mod:`annotationlib` could return annotations located in code
+blocks that are not executed at runtime.