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

2 files changed, 22 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index d29a14c..993b64e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-02-03  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclObj.c (tclCmdNameType): [Bug 2558422]: Corrected the type
+	of this structure so that extensions that write it (yuk!) will still
+	be able to function correctly.
+
 2009-02-03  Don Porter  <dgp@users.sourceforge.net>
 
 	* generic/tclStringObj.c (SetUnicodeObj):	Corrected failure of
@@ -15,18 +21,17 @@
 	significant forkage of the 8.5 and 8.6 implementations -- that are
 	better off avoided if there's no gain.
 
-	* generic/tclStringObj.c (STRING_NOMEM):  Add missing cast of
-	NULL to (char *) that upsets some compilers.  [Bug 2494093].
+	* generic/tclStringObj.c (STRING_NOMEM):  [Bug 2494093]: Add missing
+	cast of NULL to (char *) that upsets some compilers.
 
-	* generic/tclStringObj.c (Tcl_(Attempt)SetObjLength):	Added
-	protections against callers asking for negative lengths.  It is
+	* generic/tclStringObj.c (Tcl_(Attempt)SetObjLength):	[Bug 2553906]:
+	Added protections against callers asking for negative lengths.  It is
 	likely when this happens that an integer overflow is to blame.
-	[Bug 2553906].
 
 2009-02-01  David Gravereaux <davygrvy@pobox.com>
 
-	* win/makefile.vc: Allow nmake flags such as -a (rebuild
-	all) to pass down to the pkgs targets, too.
+	* win/makefile.vc: Allow nmake flags such as -a (rebuild all) to pass
+	down to the pkgs targets, too.
 
 2009-01-30  Donal K. Fellows  <dkf@users.sf.net>
 
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 */