Using git for patch management in Fedora

[Nikola Pajkovsky]

"Richard W.M. Jones" <rjones at redhat.com> writes:

> Several packages are using git for patch management.  eg:
>
> http://pkgs.fedoraproject.org/cgit/erlang.git/tree/erlang.spec#n46
> http://pkgs.fedoraproject.org/cgit/libguestfs.git/tree/libguestfs.spec?h=f20#n22
> http://pkgs.fedoraproject.org/cgit/qemu.git/tree/
> http://pkgs.fedoraproject.org/cgit/ocaml.git/tree/ocaml.spec#n16
>
> Some of these packages have invented home-brewed methods to generate
> the Patch lines in the spec file, eg:
>
> http://pkgs.fedoraproject.org/cgit/erlang.git/tree/otp-get-patches.sh
> http://pkgs.fedoraproject.org/cgit/libguestfs.git/tree/copy-patches.sh?h=f20
>
> More importantly, all are using random git repositories to store the
> exploded tree.  This makes it difficult for co-maintainers and proven
> packagers to fit in with the patch management chosen by the
> maintainer.  Usually they won't have access to the git repository for
> these patches, making it difficult to add patches and near impossible
> to upgrade to a new version.
>
> I think that git is an excellent way to manage patches, but we ought
> to think about formalizing this process.  I think the goals should be:
>
> (1) A git repository is used that co-maintainers and proven packagers
> automatically have access to.
>
> (2) A single method & script is used to update the patches in the spec file.
>
> Although there is already a git repository satisfying (1) above,
> namely dist-git, it isn't suitable for storing the exploded tree since
> commits to the spec file would conflict with commits (patches) to the
> tree.  So either a separate side repository which packages could
> opt-in to, or perhaps a separate branch of the same git repo could be
> used.  I think using a branch would require no additional
> infrastructure.
>
> For (2) I would suggest a lightweight technique where git-managed
> patches are marked in the spec file using:
>
>   ### GIT-MANAGED-PATCHES ###
>   ### END-GIT-MANGED-PATCHES ###
>
> and a simple script that replaces everything between those marks with
> PatchXXXX lines.  The script could be adapted from copy-patches.sh
> (see above).
>
> To apply the patches, a standard RPM macro could be created:
>
>   %prep
>   %setup -q
>   %{git_apply_patches}
>
> which would expand to something like:
>
>   git init
>   git config user.email "%{name}-owner at fedoraproject.org"
>   git config user.name "%{name}"
>   git add .
>   git commit -a -q -m "%{version} baseline"
>   git am %{patches}
>
> Thoughts on this?

ordering, you cannot run $ git am without ordering. Nevertheless, I
would rather use quilt for managing patches in dist-git.

-- 
Nikola