Re: GSoC idea: allow "git rebase --interactive" todo lines to take options

[Michael Haggerty <mhagger@alum.mit.edu>]

On 02/26/2014 11:52 AM, Jeff King wrote:
> On Wed, Feb 26, 2014 at 09:04:30AM +0100, Michael Haggerty wrote:
> 
>> It would be nice to support more flexibility in the todo-list commands
>> by allowing the commands to take options.  Maybe
>>
>> * Convert a commit into a merge commit:
>>
>>       pick -p c0ffeee -p e1ee712 deadbab The oneline of the commit after
> 
> This seems like a reasonable feature to me. All of your examples are
> possible with an "e"dit and another git command, but the convenience may
> be worth it (though personally, most of the examples you gave are
> particularly interesting to me[1]).

Don't forget that any of the parent commits might have been rewritten
due to the earlier lines of the rebase script.  Rebase has to map the
specified SHA-1s to their new versions.  So I don't think that this one
would be very practical to implement by hand.

Actually I think it is awkward to have to specify all of the parent
commits.  I did it this way to make it look like commit-tree's -p
option.  But any usage of this feature that *doesn't* include the
immediately preceding commit as a parent would probably be broken anyway
(for example, the preceding commit would become unreachable).

So maybe a better UI would be

    pick --merge=e1ee712 deadbab The oneline of the commit after

(even though this precludes the short form "-m" because it is already
taken by --message).

On the other hand, allowing arbitrary parents with "-p" might be a way
to make "rebase --interactive" work half-sanely with parts of history
that *already* include merge commits.  The todo list that rebase
prepares for the user would already include these "-p" lines.

What I like about allowing options in todo lists is that is that it
opens up a lot of possibilities for "git rebase --interactive" that, I
think, have previously been hampered by the restriction that commands
have to consist of a single word, and (until now) have to be abbreviable
to a single distinct letter.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/