Re: Regression in patch add?

["Martin Ågren" <martin.agren@gmail.com>]

On 10 May 2018 at 12:41, Oliver Joseph Ash <oliverjash@gmail.com> wrote:
> I just ran into a similar problem: https://stackoverflow.com/questions/50258565/git-editing-hunks-fails-when-file-has-other-hunks
>
> I can reproduce on 2.17.0. The issue doesn't occur on 2.16.2, however.
>
> Is this a bug?

I would think so. Thanks for finding this thread. To keep history
around, it would be nice to have your reproduction recipe on the list,
not just on stackoverflow. That said, I cannot reproduce on v2.17.0
using your recipe. I suspect there is something quite interesting going
on here, considering how trivial your edit is.

As a shot in the dark, does your test involve unusual file systems,
funny characters in filenames, ..? You are on some sort of Linux, right?

The first thing to try out might be something like

$ # create the initial file as before, with "bar"
$ # git add, git commit ...
$ # do the "change bar to bar1" everywhere
$ git diff >test-patch
$ git reset --hard
$ # edit the *FIRST* hunk in test.patch like before (bar1 -> bar2)
$ git apply --check test.patch && echo "ok..."
$ git apply test.patch

Does that succeed at all?

$ git diff

should now show bar2 in the first hunk and bar1 in the second hunk,
just like your edited test.patch.

If that works, it would seem that the problem is with `git add -p`, and
how it is generating the patches for `git apply`. I have some ideas
about how to debug from there, but ... How comfortable are you with
building Git from the sources? Or with temporarily fiddling around with
your Git installation? (git-add--interactive is a Perl script, so it
would be possible to edit it in place to emit various debug
information. That has potential for messing up royally, though.)

Martin