gh-142784: Make the asyncio REPL call .close() on the loop

Lib/asyncio/__main__.py

@@ -239,5 +239,6 @@ def interrupt(self) -> None:
         else:
             break
 
+    loop.close()
     console.write('exiting asyncio REPL...\n')
     sys.exit(return_code)

Lib/test/test_repl.py

@@ -409,6 +409,20 @@ def test_toplevel_contextvars_async(self):
         expected = "toplevel contextvar test: ok"
         self.assertIn(expected, output, expected)
 
+    def test_loop_was_closed(self):
+        user_input = dedent("""\
+        import atexit
+        atexit.register(\
+            lambda loop: print("loop closed:", loop.is_closed()),\
+            asyncio.get_running_loop(),\
+        )
+        """)
+        p = spawn_asyncio_repl()
+        p.stdin.write(user_input)
+        output = kill_python(p)
+        self.assertEqual(p.returncode, 0)
+        self.assertIn("loop closed: True", output)
+
 
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Library/2025-12-16-04-39-27.gh-issue-142784.HBGJag.rst

@@ -0,0 +1,3 @@
+The asyncio REPL now properly closes the loop upon the end of interactive session.
+Previously, it could cause surprising warnings.
+Contributed by Bartosz Sławecki.