gh-127537: Add __class_getitem__ to the python implementation of functools.partial (#127537)

2 files changed, 9 insertions, 0 deletions

diff --git a/Lib/functools.py b/Lib/functools.py
index eff6540..786b8ae 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -433,6 +433,9 @@ class partial:
         self._phcount = phcount
         self._merger = merger
 
+    __class_getitem__ = classmethod(GenericAlias)
+
+
 try:
     from _functools import partial, Placeholder, _PlaceholderType
 except ImportError:
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index ffd2adb..4a0252c 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -473,6 +473,12 @@ class TestPartial:
         self.assertEqual(a.cmeth(3, b=4), ((1, A, 3), {'a': 2, 'b': 4}))
         self.assertEqual(a.smeth(3, b=4), ((1, 3), {'a': 2, 'b': 4}))
 
+    def test_partial_genericalias(self):
+        alias = self.partial[int]
+        self.assertIs(alias.__origin__, self.partial)
+        self.assertEqual(alias.__args__, (int,))
+        self.assertEqual(alias.__parameters__, ())
+
 
 @unittest.skipUnless(c_functools, 'requires the C _functools module')
 class TestPartialC(TestPartial, unittest.TestCase):