On Wed, 6 May 2020 at 13:21, Fabio Valentini <decathorpe(a)gmail.com> wrote:
On Wed, May 6, 2020 at 10:37 AM Vít Ondruch <vondruch(a)redhat.com> wrote:
> Dne 05. 05. 20 v 18:37 Fabio Valentini napsal(a):
> > On Mon, May 4, 2020 at 5:06 PM Tomas Tomecek <ttomecek(a)redhat.com>
> > Hi Tomas,
> > I'll respond below with some of my experiences and opinions ...
> >> Let’s talk about dist-git, as a place where we work. For us,
> >> packagers, it’s a well-known place. Yet for newcomers, it may take a
> >> while to learn all the details. Even though we operate with projects
> >> in a dist-git repository, the layout doesn’t resemble the respective
> >> upstream project.
> >> There is a multitude of tasks we tend to perform in a dist-git repo:
> >> * Bumping a release field for sake of a rebuild.
> >> * Updating to the latest upstream release.
> >> * Resolving CVEs.
> >> * Fixing bugs by…
> >> * Changing a spec file.
> >> * Pulling a commit from upstream.
> >> * Or even backporting a commit.
> >> * And more...
> >> For some tasks, the workflow is just fine and pretty straightforward.
> >> But for the other, it’s very gruesome - the moment you need to touch
> >> patch files, the horror comes in. The fact that we operate with patch
> >> files, in a git repository, is just mind-boggling to me.
> >> Luckily, we have tooling which supports the repository layout -
> >> `fedpkg prep`, `srpm` or `mockbuild` are such handy commands - you can
> >> easily inspect the source tree or make sure your local change builds.
> >> Where am I getting with this?
> >> Over the years there have been multiple tools created to improve the
> >> development experience:
> >> rdopkg [r], rpkg-util [ru], tito [t] and probably much much more (e.g.
> >> the way Fedora kernel developers work on kernel [k]).
> > (snip)
> >> In the packit project, we work in source-git repositories. These are
> >> pretty much upstream repositories combined with Fedora downstream
> >> packaging files. An example: I recently added a project called nyancat
> >> [n] to Fedora. I have worked [w] on packaging the project in the
> >> GitHub repo and then just pushed the changes to dist-git using packit
> >> tooling. These source-git repositories can live anywhere: we have
> >> support for GitHub right now and are working on supporting pagure.
> >> Would there be an interest within the community, as opt-in, to have
> >> such source-git repositories created for respective dist-git
> >> repositories? The idea is that you would work in the source-git repo
> >> and then let packit handle synchronization with a respective dist-git
> >> repo. Our aim is to provide the contribution experience you have in
> >> GitHub when working on your packages. Dist-git would still be the
> >> authoritative source and a place where official builds are done - the
> >> source-git repo would work as a way to collaborate. We also don’t have
> >> plans right now to integrate packit into fedpkg.
> > So, in my experience, source-git might be a workable solution for
> > packages with *big* downstream modifications. However, for everything
> > else, I think it's a way to make it easy to accrue technical debt and
> > to do cargo-culting with downstream patches.
> > The vast majority of packages has *no patches* (or at most, one or two
> > of them)
> I don't really want to argue with this point, I tend to agree. Just out
> of interest, do we have some statistics to support this? O:-)
I did not have any stats when I wrote this, but now I do.
Parsing the rawhide spec files from  for lines matching
"^Patch[0-9]*:[ \t]*.*$", I get the following distribution:
number of patches: number of packages
In relative terms:
- 71% of packages have ZERO patches
- 15% have ONE patch
- 5% have TWO patches
- 3% have THREE patches
- 5% have MORE than THREE patches
Most packages have none (71%) - or at most two - patches (91%, my
original "guess" for "vast majority"), some have 3-5 patches (5%),
a minority (4%) has six patches or more. So it seems this backs up my
These are some great stats!
But I would like to note that exploded repos (or source-git repos)
have at least two other advantages.
1) they consume less space than tarballs for each version because
objects in git repo are deduplicated
2) instead of downloading/uploading tarballs, you can just do
something like: git pull --rebase upstream master; git push
So they are imho more convenient to work with even if you don't have
Continuing of communication with upstream should not be imposed by
crappy experience when maintaining patches.
It should be a question of work ethics and avoiding future conflicts
> : https://pkgs.fedoraproject.org/repo/rpm-specs-latest.tar.xz
> > > , and uses *unmodified upstream sources / tarballs*.
> > > I never want to deal with exploded upstream sources, unless I'm
> > > creating a patch for something.
> > >
> > > When it's an upstream commit that applies cleanly to the latest
> > > sources, I'll just add it in the .spec file, and let the tooling
> > > handle the rest. It's pretty neat to directly link to upstream commits
> > > (it works with github and gitlab and pagure, as far as I know), and
> > > let our tooling (spectool, fedpkg) do everything else. I don't have to
> > > download, patch, or touch sources myself in any way for that.
> > Unfortunately, in Ruby world, this unfortunately works less and less,
> > because the released packages does not contain test suite these days. So
> > if there is fix for some feature and associated test, then the patch has
> > to be modified (the test part has to be stripped or split out).
> > Otherwise I like this approach as well.
> > >
> > > When I need to make changes that I am able to push back upstream, I
> > > don't do that in packaging, but fork upstream, do my changes, create a
> > > pull request, and again point my .spec file to the patches from there.
> > > No need to touch dist-git there, instead I'm working closely with
> > > upstream.
> > >
> > > In the rare occasion that I need to make downstream-only changes with
> > > patches, I usually just explode the upstream tarball, run "git
> > > then "git add .", "git commit -m import", apply my
changes, and then
> > > do "git diff --patch > ../00-my-changes.patch" (if it's
> > > commit), or "git format-patch -o ../" if there are multiple
> > > and then delete the exploded sources again.
> > Having infrastructure for exploding sources from the package would be
> > very interesting.
> > Vít
> > >
> > > I maintain ~400 packages in fedora, and the only one with substantial
> > > downstream modifications (about 10 patches on top of upstream) is
> > > Jekyll (rubygem-jekyll), where I primarily disable tests for features
> > > that are not enabled in fedora anyway (if I didn't want to run any
> > > tests, I could just drop the number of patches to 1 or 2, making the
> > > fork unnecessary - but I like running the tests).
> > >
> > > So while I agree that for *some* packages with *huge*,
> > > non-upstreamable diffs between upstream and fedora the source-git
> > > approach might work, I doubt that it would help in 99% of cases, or
> > > even make it too easy for packagers to make more and more
> > > downstream-only changes.
> > >
> > > Fabio
> > >
> > >> The main reason I am sending this is to gather feedback from all of
> > >> you whether there is an interest in such a workflow. We don’t have
> > >> concrete plans for Fedora right now but based on your feedback we
> > >> could.
> > >>
> > >>
> > >> [r] https://github.com/softwarefactory-project/rdopkg
> > >> [ru] https://pagure.io/rpkg-util
> > >> [t] https://github.com/rpm-software-management/tito
> > >> [k]
> > >> [n] https://github.com/TomasTomecek/nyancat
> > >> [w] https://github.com/TomasTomecek/nyancat/pull/2
> > >>
> > >>
> > >> Cheers,
> > >> Tomas
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