[Starkit] corruption of starkits by double access

[Jean-Claude Wippler]

> Well, the underlying Mk4tcl would not do anything on commit if  
> there has been no change.  But yeah, probably something in the VFS  
> layer writes a value back (even if it's the same).
>
> Hmmm.  My hunch is that it's a "-1" in the parent field of the dirs  
> view, row 0.  Lemme check.  Yep, that's it: line 338 in mk4vfs.tcl  
> in tclvfs.  If you change that to not set the value if row 0  
> already exists (with its parent set to -1), then I expect the  
> commit won't do a write anymore.

Here you go, on a silver platter, a patch to TclVFS which should do it:

$ cvs diff
cvs diff: Diffing .
cvs diff: Diffing doc
cvs diff: Diffing examples
cvs diff: Diffing generic
cvs diff: Diffing http2.6
cvs diff: Diffing library
Index: library/mk4vfs.tcl
===================================================================
RCS file: /cvsroot/tclvfs/tclvfs/library/mk4vfs.tcl,v
retrieving revision 1.39
diff -u -r1.39 mk4vfs.tcl
--- library/mk4vfs.tcl  19 Oct 2005 10:58:00 -0000      1.39
+++ library/mk4vfs.tcl  27 Feb 2006 20:44:27 -0000
@@ -334,8 +334,9 @@
             mk::row append $db.dirs name <root> parent 0
         }
-       # 2001-12-13: use parent -1 for root level!
-       mk::set $db.dirs!0 parent -1
+       if {![mk::view size $db.dirs] || [mk::get $db.dirs!0 parent] ! 
= -1} {
+           mk::set $db.dirs!0 parent -1
+       }
      }
      proc _mount {{file ""} args} {
cvs diff: Diffing mac
cvs diff: Diffing tclconfig
cvs diff: Diffing tests
cvs diff: Diffing win
$

With this, you could (somehow) to detect the launch of a second copy,  
and exit without messing up the other instance of the application,  
even if that one has already started making changes.

Please let me know if you try this and how it goes, so I can check it  
into SF.

-jcw