Infinite loop in PyRun_InteractiveLoopFlags() if PyRun_InteractiveOneFlags() raises an error

Python/pythonrun.c

--- a/Python/pythonrun.c	Sun Mar 11 19:33:29 2012 +0100
+++ b/Python/pythonrun.c	Sun Mar 11 19:26:14 2012 -0700
@@ -1107,10 +1107,8 @@
         PRINT_TOTAL_REFS();
         if (ret == E_EOF)
             return 0;
-        /*
-        if (ret == E_NOMEM)
-            return -1;
-        */
+        else if (ret != 0)
+            return ret;
     }
 }
 
@@ -1144,19 +1142,22 @@
     PyObject *m, *d, *v, *w, *oenc = NULL;
     mod_ty mod;
     PyArena *arena;
-    char *ps1 = "", *ps2 = "", *enc = NULL;
+    char *ps1 = "", *ps2 = "";
+    const char *enc = NULL;
     int errcode = 0;
     _Py_IDENTIFIER(encoding);
 
     if (fp == stdin) {
         /* Fetch encoding from sys.stdin */
         v = PySys_GetObject("stdin");
-        if (v == NULL || v == Py_None)
-            return -1;
-        oenc = _PyObject_GetAttrId(v, &PyId_encoding);
-        if (!oenc)
-            return -1;
-        enc = _PyUnicode_AsString(oenc);
+        if (v == NULL || v == Py_None) 
+            enc = Py_FileSystemDefaultEncoding;
+        else {
+            oenc = _PyObject_GetAttrId(v, &PyId_encoding);
+            if (!oenc)
+                return -1;
+            enc = _PyUnicode_AsString(oenc);
+        }
         if (enc == NULL)
             return -1;
     }