Re: Union diff

[Junio C Hamano <junkio@cox.net>]

Petr Baudis <pasky@ucw.cz> writes:

>   Now, the -c option documentation says:
>
> 	  It shows the differences from each of the parents to the merge
> 	result simultaneously, instead of showing pairwise diff between
> 	a parent and the result one at a time, which '-m' option output
> 	does.
>
>   This sounds as exactly what I want. Well, the only problem is that the
> same diff command as above with -c option added produces no diff at all,
> just the header and commit messages. Did I misunderstand the -c
> description and does it do something different?

The --combined diff option is to show merges more sensibly than
plain -m option.  Now, the definition of "sensible" is to say
that a merge is not interesting if it takes a version from one
of the parents.  The paths whose results do not match any of the
parents' version are deemed interesting and are shown.

I think you could tweak and give an option to intersect_paths()
in combine-diff.c, so that paths that match one of the parents
are also included in the output.  I haven't thought about it too
much, but my gut feeling is it would not be very involved
change.