bug#5490: 23.1.91; CC Mode, after a while, everything is topmost-intro.

[Alan Mackenzie]

Hi, Jan,

Time for a top-post.  ;-)

All your answers to my questions are consistent with a bug in
c-parse-state (don't ask!).  I recently enhanced and severely optimised
this routine (it contains a cache) to deal better with certain types of
non-unusual source files.  If this cache is getting corrupted, it could
easily foul up a buffer's indentation.

Would you try one more thing, please: when you reach this buggy state
again, would you please do

    M-: (c-state-cache-init)

, and tell me if this clears the buggy state.

Thanks!



On Tue, Feb 09, 2010 at 01:45:35PM +0100, Jan Djärv wrote:
> Ok, here are some answers.
> 
> Alan Mackenzie skrev:
> >
> >OK.  Now some more details, please!
> >
> >(i) Have you ever noticed this bug happening on earlier Emacsen, in
> >  particular Emacs 23.1?
> 
> No.
> 
> >(ii) Does this bug happen every time you use Emacs this long, or only
> >  sometimes?  If the latter, how often (10%, 50%, 90%)?
> 
> 100%.  If I just keep editing it eveentually breaks.
> 
> >(iii) Do you think there might be any connection with some of the more
> >  unusual minor modes you've got switched on?  Things like
> >  auto-encryption mode?
> >
> 
> No, this doesn't seem to have any effect.
> 
> >When Emacs reaches this broken state:
> >(iv) Are all C(++) buffers in this state, or only some?  Any correlation
> >  with how many edits have been done on a buffer, or how long it's been
> >  loaded?
> 
> It is a pre buffer breakage.  One buffer usually gets borken first, while 
> the others are ok.  It is the one that I've changed/edited the most in.
> 
> >(v) What about indentation in a freshly loaded file?
> 
> No problem.
> 
> >(vi) Will M-x c-mode or M-x c++-mode clear the problem?
> 
> Yes.
> 
> >(vii) Does reverting (M-x revert-buffer) a file fix indentation?
> 
> No.
> 
> >(viii) Does killing and reloading a file fix indentation?
> 
> Yes.
> 
> >(ix) Does intentation gradually deteriorate at around 4 hours, or does it
> >  break suddenly?
> 
> Suddenly.
> 
> >(x) Do all CC Mode buffers break at the same time, or is it a "creeping
> >  death"?
> 
> Only one at the time.
> 
> 
> >Just one other thing: Could you please post a dump of your CC Mode
> >configuration (C-c C-b in a C(++) buffer).  Thanks.
> >

[ Dump appreciated! ]

-- 
Alan Mackenzie (Nuremberg, Germany).