Re: Feature request - git add --patch should have an option to discard or drop a hunk Inbox

From: Jeff King <peff@peff.net>
Date: Jan 8, 2021, 09:10 UTC
Message-ID: <X/ghgg+IdZYri1KV@coredump.intra.peff.net>
In-Reply-To: <CAJamm=+Z=88G6cH3DRkttGQkrf9tng310+p=4cKiy-GvdCG3zg@mail.gmail.com>

On Thu, Jan 07, 2021 at 11:43:45AM -0500, Jon Sagotsky wrote:

Show 10 quoted lines

> I frequently make changes to a number of files.  I use `git add -p` to
> select a number of changes and wrap them up in a commit.  Then I run
> it again to build another commit.  Wash, rinse, repeat.
> 
> Sometimes I make a change I don't intend to keep.  Maybe it's a typo,
> or some debug code, or my linter does something naughty.  As
> described, I have to skip that hunk once per commit I'm building.
> Usually this is merely inconvenient, but each pass through `git add
> -p` runs the risk of me mistakenly adding unintended changes to my
> commit.

I do something similar and have run into the same problem. There's an old discussion here going into some ideas:

  https://lore.kernel.org/git/EE89F0A1-1C07-4597-B654-035F657AD09F@me.com/

The interesting bits are I think:

  - some tools let you do this already (magit was mentioned there, and
    I'd expect vim plugins like fugitive can probably do the same; tig
    can also do so from its "stage" interface)

  - it probably wouldn't be _too_ hard to implement, because we already
    drive those actions from the same code that is invoked by "add -p"
    and "git checkout -p"; the difference is just which program we feed
    the hunks to.

  - in the most general form of the tool, it would let you take a pass
    through the hunks and annotating them. The simple common form is two
    annotations: stage these ones, discard those ones. There may be room
    for a more generalized tool, or it may just be over-complicating
    things.

    The generalized form probably shouldn't be "add -p". The simplified
    one (just adding "discard this hunk from the worktree") could
    perhaps be, though it does feel a little weird for "git add" to
    modify working tree files.

-Peff