Index: Modules/main.c
===================================================================
--- Modules/main.c	(révision 74452)
+++ Modules/main.c	(copie de travail)
@@ -543,18 +543,22 @@
 	}
 
 	if (command) {
+		char *commandStr;
 		PyObject *commandObj = PyUnicode_FromWideChar(
 		    command, wcslen(command));
 		free(command);
-		if (commandObj != NULL) {
-			sts = PyRun_SimpleStringFlags(
-				_PyUnicode_AsString(commandObj), &cf) != 0;
+		if (commandObj != NULL)
+			commandStr = _PyUnicode_AsString(commandObj);
+		else
+			commandStr = NULL;
+		if (commandStr != NULL) {
+			sts = PyRun_SimpleStringFlags(commandStr, &cf) != 0;
+			Py_DECREF(commandObj);
 		}
 		else {
 			PyErr_Print();
 			sts = 1;
 		}
-		Py_DECREF(commandObj);
 	} else if (module) {
 		sts = RunModule(module, 1);
 	}
Index: Lib/test/test_sys.py
===================================================================
--- Lib/test/test_sys.py	(révision 74452)
+++ Lib/test/test_sys.py	(copie de travail)
@@ -431,6 +431,15 @@
         out = p.stdout.read().strip()
         self.assertEqual(out, b'?')
 
+    def test_main_invalid_unicode(self):
+        p = subprocess.Popen([sys.executable, "-c", b'print("\x80")'],
+                             stderr=subprocess.PIPE)
+        p.wait()
+        self.assertEqual(p.returncode, 1)
+        err = p.stderr.read().strip()
+        self.assertEqual(err, b"UnicodeEncodeError: "
+            b"'utf-8' codec can't encode character '\\udc80' in "
+            b"position 7: surrogates not allowed")
 
 class SizeofTest(unittest.TestCase):