Re: [bug]org-mode with flyspell-mode freezes emacs

[Carsten Dominik]

On Oct 17, 2006, at 6:33, Nick Roberts wrote:

> > Anyway, I do now have a backtrace for this problem.  Can anyone 
> > extract
> > something useful from this?
>
> If Emacs is hanging, a static backtrace is unlikely to be much use.  
> You need
> to follow the instructions in DEBUG:

I have not been able to do this well, the results are very confusing to 
me, I sometimes end up in the garbage collection, sometimes in search 
functions like looking-at-1 or search-buffer.  So for now I don't have 
better information on this bug, and I don't have much time for going 
much further on this.

However, on the Lisp level, I have been able to dig deeper and found 
the following.

This error happens if flyspell is trying to check a word that is 
followed by a character with the `intangible' text property.  The words 
in the buffer where Emacs enters an infinite loop look like this

   something]]

where the "]]" carry both the invisible and the intangible text 
property.  If I remove the intangible text property and only keep 
invisible, there is no problem and Emacs functions normally. If I 
remove invisible and keep intangible, the error still happens.

> Also when a C backtrace is useful, it usually helps to include lisp 
> backtrace.
> This is output automatically with `bt' if you run Emacs under GDB from 
> the src
> directory otherwise you need to source .gdbinit (in the src directory) 
> first.

A typical lisp backtrace looks like this:

Lisp Backtrace:
"flyspell-get-word" (0x3800209)
"flyspell-word-search-backward" (0x1add4e3)
"flyspell-word" (0x3800209)
"flyspell-post-command-hook" (0x0)
"run-hooks" (0x3809c69)

or

Lisp Backtrace:
"re-search-forward" (0x1b0d1b3)
"flyspell-get-word" (0x3800209)
"flyspell-word-search-backward" (0x1add4e3)
"flyspell-word" (0x3800209)
"flyspell-post-command-hook" (0x0)
"run-hooks" (0x3809c69)

This is strange because it looks like there is an infinite loop on the 
lisp level, but when I use the lisp debugger, it is the call to 
accept-process-output where Emacs gets stuck.

I guess as a temporary fix I could remove the intangible text property, 
since invisible text is handled by the point-motion functions much like 
intangible text, so it is not really necessary to have both.  Is this a 
correct assessment?

Thanks, and sorry that I cannot be more helpful.

- Carsten