Fix for [Bug 2558422] though this area is still a mess.

FossilOrigin-Name: 3e5eb953792a476daf26bd665c9100f367ec6ec7

1 files changed, 10 insertions, 2 deletions

diff --git a/generic/tclObj.c b/generic/tclObj.c
index 93cf2f4..72de8f4 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -13,7 +13,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclObj.c,v 1.148 2009/02/03 17:15:28 dgp Exp $
+ * RCS: @(#) $Id: tclObj.c,v 1.149 2009/02/03 18:16:07 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -277,9 +277,17 @@ const Tcl_HashKeyType tclObjHashKeyType = {
  * ResolvedCmdName pointer, but DO NOT DO THIS. It seems that some extensions
  * use the second internal pointer field of the twoPtrValue field for their
  * own purposes.
+ *
+ * TRICKY POINT! Some extensions update this structure! (Notably, these
+ * include TclBlend and TCom). This is highly ill-advised on their part, but
+ * does allow them to delete a command when references to it are gone, which
+ * is fragile but useful given their somewhat-OO style. Because of this, this
+ * structure MUST NOT be const so that the C compiler puts the data in
+ * writable memory. [Bug 2558422]
+ * TODO: Provide a better API for those extensions so that they can coexist...
  */
 
-static const Tcl_ObjType tclCmdNameType = {
+Tcl_ObjType tclCmdNameType = {
     "cmdName",				/* name */
     FreeCmdNameInternalRep,		/* freeIntRepProc */
     DupCmdNameInternalRep,		/* dupIntRepProc */