gh-87109: singledispatchmethod exposes registry and dispatch

Doc/whatsnew/3.11.rst

@@ -767,6 +767,9 @@ functools
 
   (Contributed by Yurii Karabas in :issue:`46014`.)
 
+* :class:`functools.singledispatchmethod` exposes members 'registry' and
+  'dispatch'. (Contributed by Weipeng Hong in :issue:`42943`.)
+
 
 .. _whatsnew311-gzip:
 

Lib/functools.py

@@ -1142,6 +1142,14 @@ def __wrapped__(self):
     def register(self):
         return self._unbound.register
 
+    @property
+    def dispatch(self):
+        return self._unbound.dispatcher.dispatch
+
+    @property
+    def registry(self):
+        return self._unbound.dispatcher.registry
+
 
 ################################################################################
 ### cached_property() - property result cached as instance attribute

Lib/test/test_functools.py

@@ -2853,6 +2853,13 @@ def _(self, arg):
         self.assertEqual(a.arg, "base")
         aa = A()
         self.assertNotHasAttr(aa, 'arg')
+        def fun(self, arg):
+            pass
+        A.t.register(list, fun)
+        self.assertIs(fun, A.t.dispatch(list))
+        self.assertIs(fun, A().t.dispatch(list))
+        self.assertIs(fun, A.t.registry[list])
+        self.assertIs(fun, A().t.registry[list])
 
     def test_staticmethod_register(self):
         class A:

Misc/NEWS.d/next/Library/2021-12-09-23-00-06.bpo-42943.fVg5Bz.rst

@@ -0,0 +1,2 @@
+The :class:`functools.singledispatchmethod` exposes members 'registry' and
+'dispatch'. Patch by Weipeng Hong.