protect Tcl_GetIndexFromObjStruct from empty strings in table

1 files changed, 16 insertions, 7 deletions

diff --git a/generic/tclIndexObj.c b/generic/tclIndexObj.c
index b206b35..85e0730 100644
--- a/generic/tclIndexObj.c
+++ b/generic/tclIndexObj.c
@@ -302,6 +302,10 @@ Tcl_GetIndexFromObjStruct(
 	    entryPtr = NEXT_ENTRY(entryPtr, offset), idx++) {
 	for (p1 = key, p2 = *entryPtr; *p1 == *p2; p1++, p2++) {
 	    if (*p1 == '\0') {
+		if (p1 == key) {
+		    /* empty keys never match */
+		    continue;
+		}
 		index = idx;
 		goto done;
 	    }
@@ -356,26 +360,31 @@ Tcl_GetIndexFromObjStruct(
 	 * Produce a fancy error message.
 	 */
 
-	int count;
+	int count = 0;
 
 	TclNewObj(resultPtr);
+	entryPtr = tablePtr;
+	while ((*entryPtr != NULL) && !**entryPtr) {
+	    entryPtr = NEXT_ENTRY(entryPtr, offset);
+	}
 	Tcl_AppendStringsToObj(resultPtr,
 		(numAbbrev>1 && !(flags & TCL_EXACT) ? "ambiguous " : "bad "),
 		msg, " \"", key, NULL);
-	if (STRING_AT(tablePtr, offset, 0) == NULL) {
+	if (*entryPtr == NULL) {
 	    Tcl_AppendStringsToObj(resultPtr, "\": no valid options", NULL);
 	} else {
 	    Tcl_AppendStringsToObj(resultPtr, "\": must be ",
-		    STRING_AT(tablePtr, offset, 0), NULL);
-	    for (entryPtr = NEXT_ENTRY(tablePtr, offset), count = 0;
-		    *entryPtr != NULL;
-		    entryPtr = NEXT_ENTRY(entryPtr, offset), count++) {
+		    *entryPtr, NULL);
+	    entryPtr = NEXT_ENTRY(entryPtr, offset);
+	    while (*entryPtr != NULL) {
 		if (*NEXT_ENTRY(entryPtr, offset) == NULL) {
 		    Tcl_AppendStringsToObj(resultPtr, (count > 0 ? "," : ""),
 			    " or ", *entryPtr, NULL);
-		} else {
+		} else if (**entryPtr) {
 		    Tcl_AppendStringsToObj(resultPtr, ", ", *entryPtr, NULL);
+		    count++;
 		}
+		entryPtr = NEXT_ENTRY(entryPtr, offset);
 	    }
 	}
 	Tcl_SetObjResult(interp, resultPtr);