Added comments warning against certain optimizations

1 files changed, 9 insertions, 1 deletions

diff --git a/generic/tclListObj.c b/generic/tclListObj.c
index 35db836..6887207 100644
--- a/generic/tclListObj.c
+++ b/generic/tclListObj.c
@@ -10,7 +10,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclListObj.c,v 1.35 2007/02/24 18:55:43 dgp Exp $
+ * RCS: @(#) $Id: tclListObj.c,v 1.36 2007/03/02 16:06:33 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -804,6 +804,14 @@ Tcl_ListObjReplace(
 	}
     }
 
+    /* 
+     * Note that when count == 0 and objc == 0, this routine is logically
+     * a no-op, removing and adding no elements to the list.  However, by
+     * flowing through this routine anyway, we get the important side effect
+     * that the resulting listPtr is a list in canoncial form.  This is
+     * important.  Resist any temptation to optimize this case.
+     */
+
     listRepPtr = (List *) listPtr->internalRep.twoPtrValue.ptr1;
     elemPtrs = &listRepPtr->elements;
     numElems = listRepPtr->elemCount;