[RFC] New core command: graft

[Matt Mackall]

On Mon, 2011-10-10 at 00:52 +0200, Pierre-Yves David wrote:
> On 10 oct. 2011, at 00:23, Matt Mackall wrote:
> 
> > The implementation I have so far works, but there's still some work to
> > do:
> > 
> > - needs to actually support --continue
> > - needs testing
> > 
> > Among other things, I'm looking for feedback on the UI and what features
> > are critical. Right now, it copies the details of grafted changesets
> > (user/date/description) verbatim. That's an ok default, but it seems
> > like we'd like to be able to tweak that.
> 
> 
> I'm not a fan of the --continue switch.

I'm not either, but I haven't heard a better answer yet.

>  We could use the same approach than in merge, recording that we are
> doing something special and refuse to do most operation but a commit.
> A conflict during graft would ask you to resolve and commit. Using
> commit would allow to use the existing UI to tweak the default value
> if needed.

This is tricky because it implies commit has to know that we were in the
middle of a graft to find the commit details. And of course, it needs to
know how to continue a multi-revision graft that breaks in the middle.

I'm somewhat tempted to make graft only work on one changeset at a time
so that you can't accidentally make a huge mess that can't be rolled
back. This would make it more similar to backout.

>  After the commit, the graft will continue until it complete.
> Interactive (-i, --interactive) graft would ask for an explicit commit
> for each grafted changeset.
> 
> A more stupid question is : "how is graft different from a rebase
> --keep where you can specify where to stop your rebasing ?"

a) it's built into core
b) it's easier to use

In terms of (b), graft is more natural in that it pull changesets from
'there' to 'here', while rebase by default moves your current branch
(and has a bunch of confusing options if that's not what you want to
do).

It's also probably simpler to think of rebase as being a bunch of grafts
+ a strip at the end rather than thinking of graft as a special
not-yet-implemented rebase mode.

-- 
Mathematics is the supreme nostalgia of our time.