Re: [Quilt-dev] What about git-diff as an alternative diff backend?

[Andreas Grünbacher]

Am Fr., 24. Jan. 2025 um 09:54 Uhr schrieb Greg KH <greg@kroah.com>:
> On Fri, Jan 24, 2025 at 09:37:46AM +0100, Petr Tesarik via Quilt-dev wrote:
> > Hi all,
> >
> > following a recent SUSE-internal discussion about differences between
> > patches produced by Git and patches produced by GNU diff, I wonder if
> > we could allow git-diff as an alternative backend in quilt.
> >
> > FWIW I am willing to send in patches, but I want to make sure they
> > would be appreciated before I invest my time.

I assume you mean "git diff" as well as "git apply". Supporting those
would certainly help; it would probably give quilt full binary diff
support "for free". But that won't be easy to achieve: quilt relies on
GNU patch to create backup files when applying patches, and it's those
backup files that "quilt diff" and similar commands operate against.

In addition, the last time I checked, "git apply" had weird heuristics
built in instead of accepting a specific strip level; see GNU patch's
-p / --strip option. Quilt remembers the strip levels of patches and
preserves strip levels 0 and 1 when refreshing patches.

> I know I would like this as I had a long-standing bug somewhere in the
> stable queues that was tripped up by using gnu diff instead of git-diff.
>
> I think the issue had to do with permission settings of files which
> git-diff handled and GNU diff didn't?  Maybe, I can't quite recall it at
> the moment but can dig it up if needed.
>
> I remember trying to override the GNU diff usage in quilt, but couldn't
> figure out how to get it to work, so yes, I would like this feature if
> possible.

Was that before GNU patch had basic git diff support? GNU patch and
diff still don't do binary patches.

Thanks,
Andreas