Nice RPM / git patch management trick

As far as I know, this trick was invented by Peter Jones. Edit: Or it could be ajax?

Parted in Fedora uses a clever method to manage patches with git and “git am”.

%prep
%setup -q
# Create a git repo within the expanded tarball.
git init
git config user.email "..."
git config user.name "..."
git add .
git commit -a -q -m "%{version} baseline."
# Apply all the patches on top.
git am %{patches}

The background is that there is a git repo somewhere else which stores the unpacked baseline parted tarball, plus patches (stored as commits) on top.

I assume that Peter exports the commits using git format-patch. At build time these are applied on top of the tarball using git am.

There are two clear advantages:

• No need to have lots of duplicate %patch lines in the spec file.
• git-am restores permissions and empty files properly, which regular patch does not do.

With libguestfs in RHEL 6 we have roughly 80 patches, so managing these patches is very tedious, and this will greatly simplify things.