bug#60126: 30.0.50; vc-git-checkin: Offer to unstage conflicting changes

[Dmitry Gutov]

On 24/12/2022 20:22, Sean Whitton wrote:

> Now that we understand clearly what we want it to do, I bet the code in
> vc-checkin-git could be simplified (vc-git--stash-staged-changes is
> fine).  So I'll see about doing that, with some tests, as you suggest.
>
> Let me ask you about the parsing of the 'diff --git' lines.
...
> Do you have any better ideas of how to extract the filename from the git
> --diff line, or perhaps a proof that my approach can't fail? :)

I don't know. You could try

  (and (looking-at diff-file-header-re) (match-string 1))

instead, but it matches a different line (one that starts with "---").

> I wasn't
> happy with my regexp approach to extracting the filename.  I'm not sure
> it can actually fail, but the current codes assumes it can, and that
> adds complexity.

Not sure which failure you are referring to, but the process of removing 
already-staged hunks from vc-git-patch-string can indeed fail, because 
the hunks might be staged, or might be not. The idea was to support both 
situations.

> The --src-prefix, --dst-prefix and --no-prefix options to git-diff(1)
> might be relevant, but then we couldn't use a simple string-match to
> find hunks in vc-git-patch-string.

Right.