Re: [vile] vile-9.6e.patch.gz

[Thomas Dickey]

On Thu, 7 Feb 2008, Paul Fox wrote:

> >    + fix an incorrect reference in chgd_fences() which was exposed by
> >      changing fence-pairs more than once in .vilerc, dating from 5.3l
> >      (report by Steven Lembark).
>
> can you expand on this?  what does "changing fence-pairs more
> than once" mean?

The essential part of the example:

        set fence-pairs={}

        ~with define-mode perl
                fence-pairs {}[]

> there's been a long-standing bug that i think i've mentioned
> before (possibly years ago) that causes fence-match operations to
> very occasionally be off by one character.  could this be what
> you're referring to?  i've never been able to reproduce it.

It could be the same thing.  I couldn't _reproduce_ it (no visible 
symptoms), but running with valgrind and Steven's .vilerc, I saw a place 
where I had used the wrong pointer in a VAL struct (something that I 
recall doing at least once long ago).  Since it's only in the chgd_fences 
code, it's only a problem if the value happens to be altered - and it took 
two steps for the code to get around to trying to use the memory.

His symptom had the first tab off by one (to the left) - then after that, 
it was sort of okay.

Even with valgrind, it took some time to realize where the bug was - I 
looked at that line several times.

--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net