gh-126451: Register contextvars.Context to collections.abc.Mapping

Lib/contextvars.py

@@ -1,4 +1,8 @@
+import collections.abc
 from _contextvars import Context, ContextVar, Token, copy_context
 
 
 __all__ = ('Context', 'ContextVar', 'Token', 'copy_context')
+
+
+collections.abc.Mapping.register(Context)

Lib/test/test_context.py

@@ -1,3 +1,4 @@
+import collections.abc
 import concurrent.futures
 import contextvars
 import functools
@@ -350,6 +351,15 @@ def ctx2_fun():
 
         ctx1.run(ctx1_fun)
 
+    def test_context_isinstance(self):
+        ctx = contextvars.Context()
+        self.assertIsInstance(ctx, collections.abc.Mapping)
+
+        mapping_methods = ("__getitem__", "__iter__", "__len__", "__contains__", "keys",
+                           "items", "values", "get", "__eq__", "__ne__")
+        for name in mapping_methods:
+            self.assertIn(name, dir(ctx))
+
     @isolated_context
     @threading_helper.requires_working_threading()
     def test_context_threads_1(self):

Misc/NEWS.d/next/Library/2024-11-05-11-28-45.gh-issue-126451.XJMtqz.rst

@@ -0,0 +1,2 @@
+Register the :class:`!contextvars.Context` type to
+:class:`!collections.abc.Mapping`.