Issue #28192: Don't import readline in isolated mode
diff --git a/Modules/main.c b/Modules/main.c
index 0b82f48..6986d94 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -703,7 +703,8 @@
     PySys_SetArgv(argc-_PyOS_optind, argv+_PyOS_optind);
 
     if ((Py_InspectFlag || (command == NULL && filename == NULL && module == NULL)) &&
-        isatty(fileno(stdin))) {
+        isatty(fileno(stdin)) &&
+        !Py_IsolatedFlag) {
         PyObject *v;
         v = PyImport_ImportModule("readline");
         if (v == NULL)