From 229e18db61ac39fb481e3652b2674a339fdf291e Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Sun, 3 Dec 2023 00:41:03 +0000
Subject: [PATCH] [3.12] gh-112618: Make Annotated cache typed (GH-112619)
 (GH-112628) (cherry picked from commit
 2a378ca2efcb91db4b04fb4e052424fd610ffbc9)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
---
 Lib/test/test_typing.py                       | 34 +++++++++++++++++++
 Lib/typing.py                                 |  9 +++--
 ...-12-02-12-55-17.gh-issue-112618.7_FT8-.rst |  2 ++
 3 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-12-02-12-55-17.gh-issue-112618.7_FT8-.rst

diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index f663fbd8679e0e..b0e3ca96fd1c7f 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -7627,6 +7627,40 @@ class X(Annotated[int, (1, 10)]): ...
         self.assertEqual(X.__mro__, (X, int, object),
                          "Annotated should be transparent.")
 
+    def test_annotated_cached_with_types(self):
+        class A(str): ...
+        class B(str): ...
+
+        field_a1 = Annotated[str, A("X")]
+        field_a2 = Annotated[str, B("X")]
+        a1_metadata = field_a1.__metadata__[0]
+        a2_metadata = field_a2.__metadata__[0]
+
+        self.assertIs(type(a1_metadata), A)
+        self.assertEqual(a1_metadata, A("X"))
+        self.assertIs(type(a2_metadata), B)
+        self.assertEqual(a2_metadata, B("X"))
+        self.assertIsNot(type(a1_metadata), type(a2_metadata))
+
+        field_b1 = Annotated[str, A("Y")]
+        field_b2 = Annotated[str, B("Y")]
+        b1_metadata = field_b1.__metadata__[0]
+        b2_metadata = field_b2.__metadata__[0]
+
+        self.assertIs(type(b1_metadata), A)
+        self.assertEqual(b1_metadata, A("Y"))
+        self.assertIs(type(b2_metadata), B)
+        self.assertEqual(b2_metadata, B("Y"))
+        self.assertIsNot(type(b1_metadata), type(b2_metadata))
+
+        field_c1 = Annotated[int, 1]
+        field_c2 = Annotated[int, 1.0]
+        field_c3 = Annotated[int, True]
+
+        self.assertIs(type(field_c1.__metadata__[0]), int)
+        self.assertIs(type(field_c2.__metadata__[0]), float)
+        self.assertIs(type(field_c3.__metadata__[0]), bool)
+
 
 class TypeAliasTests(BaseTestCase):
     def test_canonical_usage_with_variable_annotation(self):
diff --git a/Lib/typing.py b/Lib/typing.py
index 95f855b5a88452..85166dfd946314 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -2214,9 +2214,14 @@ class Annotated:
     def __new__(cls, *args, **kwargs):
         raise TypeError("Type Annotated cannot be instantiated.")
 
-    @_tp_cache
     def __class_getitem__(cls, params):
-        if not isinstance(params, tuple) or len(params) < 2:
+        if not isinstance(params, tuple):
+            params = (params,)
+        return cls._class_getitem_inner(cls, *params)
+
+    @_tp_cache(typed=True)
+    def _class_getitem_inner(cls, *params):
+        if len(params) < 2:
             raise TypeError("Annotated[...] should be used "
                             "with at least two arguments (a type and an "
                             "annotation).")
diff --git a/Misc/NEWS.d/next/Library/2023-12-02-12-55-17.gh-issue-112618.7_FT8-.rst b/Misc/NEWS.d/next/Library/2023-12-02-12-55-17.gh-issue-112618.7_FT8-.rst
new file mode 100644
index 00000000000000..c732de15609c96
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-12-02-12-55-17.gh-issue-112618.7_FT8-.rst
@@ -0,0 +1,2 @@
+Fix a caching bug relating to :data:`typing.Annotated`.
+``Annotated[str, True]`` is no longer identical to ``Annotated[str, 1]``.