[22.1.90]: Point before start of properties

["Marshall, Simon" <Simon.Marshall@misys.com>]

During pretesting before 22.1 I reported a problem whereby occasionally
I would see the minibuffer message "Error in menu-bar-update-hook:
(error Point before start of properties)" and the hook would be left
with a value of nil.  (See "Error in menu-bar-update-hook: (error Point
before start of properties)" from July 2006.)  At the time I had a go at
tracking it down but without any success, and it continues to bite me
every so often to this day.  So, occasionally, I have to do M-x msb-mode
twice to turn msb-mode off and then back on again.  

I was hoping the pretest version might magically have a fix for it, but
unfortunately not.  I figured I would have another go at debugging it
and found that it seems suspiciously easy to reproduce.  All I have to
do is this:

(gdb) b intervals.c:794
Breakpoint 1 at 0x195d90: file intervals.c, line 794.
(gdb) r -Q

Then in emacs do C-x C-f ~/.../src/intervals.c RET and bang:

Breakpoint 1, update_interval (i=0x8b1af4, pos=1771) at intervals.c:794
794                 error ("Point before start of properties");
(gdb) 

If I don't set the breakpoint before I run emacs, but visit the file and
only then in gdb put the breakpoint on and continue, I can trigger this
error just by scrolling the window with the scrollbar.

It seems too easy to trigger this error, so I am not sure I am really
seeing the same problem that occasionally results in
menu-bar-update-hook being set to nil.  Is the triggering of this error
normal in certain circumstances?  If not, is the above enough for
someone to take a look at it?  Otherwise, is there anything I can do to
track down the problem for menu-bar-update-hook?

Simon.

In GNU Emacs 22.1.90.1 (sparc-sun-solaris2.8, Motif Version 2.1.0)
 of 2008-01-31 on risksun2
Windowing system distributor `Hummingbird Ltd.', version 11.0.100015
configured using `configure
'--x-includes=/usr/openwin/include:/usr/dt/include:/usr/local/include:/u
sr/local/X11/include'
'--x-libraries=/usr/openwin/lib:/usr/dt/lib:/usr/local/lib:/usr/local/X1
1/lib' '--with-x-toolkit=motif''


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