Re: Develop a patch series with git?

From: Jeff King <peff@peff.net>
Date: Feb 11, 2020, 20:00 UTC
Message-ID: <20200211200044.GG2127797@coredump.intra.peff.net>
In-Reply-To: <trinity-f39d7ed5-e4c9-45fe-944c-b5cb101cfdcd-1581412940557@3c-app-gmx-bap62>

On Tue, Feb 11, 2020 at 10:22:20AM +0100, Steve Keller wrote:

Show 16 quoted lines

> I wonder how git supports developing a series of small patches.  In my
> usual development I go back and forth along a series of patches before
> I can commit them all.  I use quilt for that.
> 
> Say I want to add feature FOO and start a patch "FOO" editing some
> source file.  In the process of doing so I realize that I need an
> extension of some function to base my patch on, so I do "quilt pop" to
> undo patch FOO and insert a new patch BAR and then re-apply FOO by
> calling quilt push.  No I can use the new extension from BAR in my
> current patch FOO.  The patch series often contains quite a number of
> patches and I push, pop, and edit these patches quite often.  Only
> when everything is done I use git commit all the patches into the
> repository.
> 
> My question is whether there is git functionality to replace quilt.
> Or is the combination of quilt and git common?

Another responder mentioned "rebase -i", which is the most direct equivalent. But on a smaller scale, also look at "git add -p", which lets you selectively stage hunks for commit.

So quite often my flow is something like:

  1. Messy writing and refactoring, while I get a handle on what my
     changes are going to be.

  2. "git add -p" to pull out some hunks related to refactoring, then
     "git commit" to give it a rough commit message.

  3. Repeat step 2 (with maybe some more step 1 in between) as necessary
     until you have a sequence of rough patches.

  4. Revisit each patch individually with "rebase -i", possibly
     re-ordering, fixing bugs, fleshing out commit messages, etc.
     Another useful tool here is:

       git rebase -x "make test"

     which makes sure that the intermediate steps are all correct.

-Peff