1 files changed, 10 insertions, 0 deletions
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index 11a57e9..60b08ae 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -3025,6 +3025,16 @@ UpdateStringOfString(
 {
     String *stringPtr = GET_STRING(objPtr);
 
+    /*
+     * This routine is only called when we need to generate the
+     * string rep objPtr->bytes because it does not exist -- it is NULL.
+     * In that circumstance, any lingering claim about the size of
+     * memory pointed to by that NULL pointer is clearly bogus, and
+     * needs a reset.
+     */
+
+    stringPtr->allocated = 0;
+
     if (stringPtr->numChars == 0) {
 	TclInitStringRep(objPtr, tclEmptyStringRep, 0);
     } else {