[Gnu-arch-users] hate bk? here's a challenge

[Tom Lord]

Back in August, Zack Brown forwarded some discussion from lkml about
BK features that are "must haves" for a BK replacement.

One item that catches my eye is:


On 27 Dec 2001, Larry McVoy said:
> in the interesting case (i.e.,
> it won't patch cleanly), both text based and GUI based tools are available
> to help with the merge.  They are better than anything you're used to or
> I'll eat my hat.  For example, if you are a CVS user, you are used to this:
> 
>     <<<<<<< local slib.c 1.645
>                   sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, s->proj);
>                   assert(HASGRAPH(sc));
>                   sccs_sdelta(sc, sccs_ino(sc), file);
>     <<<<<<< remote slib.c 1.642.2.1
>                   sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, p);
>                   assert(sc->tree);
>                   sccs_sdelta(sc, sc->tree, file);
>     >>>>>>>
> 
> but we can give you this:
> 
>     <<<<<<< local slib.c 1.642.1.6 vs 1.645
>                   sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, s->proj);
>     -             assert(sc->tree);
>     -             sccs_sdelta(sc, sc->tree, file);
>     +             assert(HASGRAPH(sc));
>     +             sccs_sdelta(sc, sccs_ino(sc), file);
>     <<<<<<< remote slib.c 1.642.1.6 vs 1.642.2.1
>     -             sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, s->proj);
>     +             sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, p);
>                   assert(sc->tree);
>                   sccs_sdelta(sc, sc->tree, file);
>     >>>>>>>
> 
> Why is that better?  It's essentially two inline context diffs, so you can
> see what each side did.  Much easier to merge when you can tell what is
> going on.
> 
> The GUI tools give you the second style as well as some extra windows
> so you can see the checkin comments associated with both the deleted and
> the added lines, which gives you yet more information.


So, the challenge is:  who wants to add support to GNU diff3 to emit 
context diffs in more or less that style?

-t