pythongh-118817: Fix asyncio REPL on Windows (python#118819)

Author: Eclips4

Lib/asyncio/__main__.py

@@ -108,7 +108,7 @@ def run(self):
     try:
         import readline  # NoQA
     except ImportError:
-        pass
+        readline = None
 
     interactive_hook = getattr(sys, "__interactivehook__", None)
 
@@ -122,8 +122,9 @@ def run(self):
         except:
             pass
         else:
-            completer = rlcompleter.Completer(console.locals)
-            readline.set_completer(completer.complete)
+            if readline is not None:
+                completer = rlcompleter.Completer(console.locals)
+                readline.set_completer(completer.complete)
 
     repl_thread = REPLThread()
     repl_thread.daemon = True

Lib/test/test_repl.py

@@ -7,7 +7,7 @@
 from textwrap import dedent
 from test import support
 from test.support import cpython_only, has_subprocess_support, SuppressCrashReport
-from test.support.script_helper import kill_python
+from test.support.script_helper import kill_python, assert_python_ok
 from test.support.import_helper import import_module
 
 
@@ -195,6 +195,9 @@ def bar(x):
         expected = "(30, None, [\'def foo(x):\\n\', \'    return x + 1\\n\', \'\\n\'], \'<stdin>\')"
         self.assertIn(expected, output, expected)
 
+    def test_asyncio_repl_is_ok(self):
+        assert_python_ok("-m", "asyncio")
+
 
 
 class TestInteractiveModeSyntaxErrors(unittest.TestCase):