[PATCH 0 of 2] Better support for diffing individual changesets.

[Dirkjan Ochtman]

Matt Mackall <mpm <at> selenic.com> writes:
> Ok, you've convinced me it's an interesting feature, I'm just not sure I
> like having even more options for diff. It would be nice if we had some
> standard way of referring to "the first parent of changeset x", "the
> ancestor of x and y", etc. and then we'd have more general capability
> everywhere without new options.

Well, diffing against the parent is something of a special case. Subversion
added a -c option for diff after several years, because the benefits of this
simple option far outweighed the costs of spending an option on this. FWIW, I've
wanted this option since I started using Mercurial: being able to use diff
(rather than export, which is useful but has a very different connotation) to
view a revision's changes is pretty fundamental use, and the current way
(figuring out parents, then using diff -r -r) is verbose and cumbersome. This
also came up in discussions with Mozilla people, who wanted it.

BTW, I think the cost of having diff options should be limited somewhat by the
fact that most of the options are copied from GNU diff.

I'm not sure I care much for --switch-parents, we should rather use tonfa's
merge diffs once that's ready, but the basic use of diff against first parent is
exceedingly simple though in my opinion thoroughly useful.

Cheers,

Dirkjan