gh-132064: Make annotationlib use __annotate__ if only it is present (#132195)

Lib/test/test_functools.py

@@ -1,4 +1,5 @@
 import abc
+from annotationlib import Format, get_annotations
 import builtins
 import collections
 import collections.abc
@@ -22,6 +23,7 @@ from inspect import Signature
 
 from test.support import import_helper
 from test.support import threading_helper
+from test.support import EqualToForwardRef
 
 import functools
 
@@ -2075,6 +2077,34 @@ class TestLRU:
         self.assertEqual(str(Signature.from_callable(lru.cache_info)), '()')
         self.assertEqual(str(Signature.from_callable(lru.cache_clear)), '()')
 
+    def test_get_annotations(self):
+        def orig(a: int) -> str: ...
+        lru = self.module.lru_cache(1)(orig)
+
+        self.assertEqual(
+            get_annotations(orig), {"a": int, "return": str},
+        )
+        self.assertEqual(
+            get_annotations(lru), {"a": int, "return": str},
+        )
+
+    def test_get_annotations_with_forwardref(self):
+        def orig(a: int) -> nonexistent: ...
+        lru = self.module.lru_cache(1)(orig)
+
+        self.assertEqual(
+            get_annotations(orig, format=Format.FORWARDREF),
+            {"a": int, "return": EqualToForwardRef('nonexistent', owner=orig)},
+        )
+        self.assertEqual(
+            get_annotations(lru, format=Format.FORWARDREF),
+            {"a": int, "return": EqualToForwardRef('nonexistent', owner=lru)},
+        )
+        with self.assertRaises(NameError):
+            get_annotations(orig, format=Format.VALUE)
+        with self.assertRaises(NameError):
+            get_annotations(lru, format=Format.VALUE)
+
     @support.skip_on_s390x
     @unittest.skipIf(support.is_wasi, "WASI has limited C stack")
     @support.skip_if_sanitizer("requires deep stack", ub=True, thread=True)