[3.14] gh-82183: Do not restart the busy IDLE shell when running without restart (GH-152745)

Lib/idlelib/idle_test/test_runscript.py

@@ -2,6 +2,7 @@
 
 from idlelib import runscript
 import unittest
+from unittest import mock
 from test.support import requires
 from tkinter import Tk
 from idlelib.editor import EditorWindow
@@ -28,6 +29,26 @@ def test_init(self):
         sb = runscript.ScriptBinding(ew)
         ew._close()
 
+    def test_run_module_event_shell_busy_no_restart(self):
+        # gh-82183: running without restarting the busy shell aborts.
+        ew = EditorWindow(root=self.root)
+        sb = runscript.ScriptBinding(ew)
+        sb.getfilename = mock.Mock(return_value='test.py')
+        sb.checksyntax = mock.Mock(return_value='code')
+        sb.tabnanny = mock.Mock(return_value=True)
+        sb.shell = shell = mock.Mock()
+        shell.executing = True
+        interp = shell.interp
+        with mock.patch.object(runscript, 'CustomRun') as customrun:
+            # Restart shell unchecked.
+            customrun.return_value.result = (['arg'], False)
+            result = sb.run_module_event(None, customize=True)
+        self.assertEqual(result, 'break')
+        interp.display_executing_dialog.assert_called_once()
+        interp.restart_subprocess.assert_not_called()
+        interp.runcode.assert_not_called()
+        ew._close()
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)

Lib/idlelib/runscript.py

@@ -139,6 +139,10 @@ def run_module_event(self, event, *, customize=False):
                 return 'break'
         self.cli_args, restart = run_args if customize else ([], True)
         interp = self.shell.interp
+        if self.shell.executing and not restart:
+            # Cannot run without restarting the busy shell (gh-82183).
+            interp.display_executing_dialog()
+            return 'break'
         if pyshell.use_subprocess and restart:
             interp.restart_subprocess(
                     with_cwd=False, filename=filename)

Misc/NEWS.d/next/IDLE/2026-07-01-19-00-00.gh-issue-82183.rNsTrt.rst

@@ -0,0 +1,3 @@
+When the shell is busy running code, using "Run... Customized" with "Restart
+shell" unchecked now reports that the shell is executing instead of
+restarting it anyway.