1 files changed, 5 insertions, 1 deletions
diff --git a/Python/codecs.c b/Python/codecs.c
index bed2453..9c0a3fa 100644
--- a/Python/codecs.c
+++ b/Python/codecs.c
@@ -147,7 +147,9 @@ PyObject *_PyCodec_Lookup(const char *encoding)
     if (v == NULL) {
         return NULL;
     }
-    PyUnicode_InternInPlace(&v);
+
+    /* Intern the string. We'll make it immortal later if lookup succeeds. */
+    _PyUnicode_InternMortal(interp, &v);
 
     /* First, try to lookup the name in the registry dictionary */
     PyObject *result;
@@ -200,6 +202,8 @@ PyObject *_PyCodec_Lookup(const char *encoding)
         goto onError;
     }
 
+    _PyUnicode_InternImmortal(interp, &v);
+
     /* Cache and return the result */
     if (PyDict_SetItem(interp->codecs.search_cache, v, result) < 0) {
         Py_DECREF(result);