Re: 24.0.50; args-out-of-range while reverting C++ header file

[Miles Bader <miles@gnu.org>]

Alan Mackenzie <acm@muc.de> writes:
>> C-x C-f some-moderately-big-header-file.h
>> <make some big modification on disk to the file>
>> M-x revert-buffer
>> Lisp error: (args-out-of-range 580 36722)
>
> I do this, but can't reproduce the error.  Can you please be precise
> about which file.h triggers the problem (send me a copy of it if it's
> outside of Emacs, please) and what the "big modification" is.
>
> I built the latest Emacs-24 last night.  I tried it with loading
> .../emacs/src/lisp.h, then

Hmm, I'm getting similar behavior, but I'm not using "revert-buffer".

I think the basic scenario is:

  1) I have a buffer visiting config.h (autoconf-generated)

  2) I re-run make or something, which causes config.h to be regenerated
  and changed (the latter's important, as autoconf doesn't touch it if
  the contents don't actually change)

  3) I visit config.h again with find-file; since it's already in a
  buffer, but has changed, Emacs asks the usual question in this
  situation:

     File config.h changed on disk.  Reread from disk? (yes or no) 

  4) I answer "yes RET", and then I get an error:

     c-clear-char-property-with-value-function: Args out of range: 464, 3922

  [and don't end up visiting the vile]

  5) I use find-file again on config.h; this time, Emacs asks:

     File config.h changed on disk.  Discard your edits? (yes or no)

  [despite the fact that I never actually made any changes to that
  buffer; I guess the failed update changed it.]

  6) I answer "yes RET", and this time am left in the config.h buffer,
  properly updated from disk.

I think this recipe can be fairly easily followed (you can just touch
the file or something, of course, instead of getting autoconf to change
it).

Thanks,

-Miles

-- 
gravity a demanding master ... soft soft snow