After I answered a question on the devel list today about getting one’s hands on an old testing package for Fedora that had been obsoleted or removed, Josh Boyer one-upped me by providing some easy instructions. I figured I would tip my fedora to him by building a blog post on his work. Nice one, Josh!
When someone builds an official Fedora package, whether it ultimately gets moved to stable or not, there’s a record for it in Koji, the Fedora package build system. You can use the search bar on the Koji website to find the package or build you’re inerested in. In the resulting page, you’ll find the build is labeled with the git commit from which the build came — it’s the long checksum in the “Task” line.
The package may not be there anymore, but that git label is all you need. It represents the position in the repository history from which the packager built that package. You can find that point in history and re-execute the same steps. You can then clone the package’s git repository, reset the HEAD to the proper commit, and send a scratch build to the Koji builder. Once the build is done, you can download the results.
Caveat: It’s possible that other package changes in Fedora might make a build of that exact point in history difficult later. Be aware this solution isn’t perfect, and you may simply want to find an alternate build in Koji that still exists and suits your purpose, or use the latest updates-testing or stable package instead. But in the hopes people find it useful, here are the commands, assuming the package name is “foobar” on Fedora 16 and the git commit of interest in starts with “0123abcd” (and let’s hope I do better than in the last post in which I gave tips):
su -c 'yum install fedora-packager' cd /tmp fedpkg clone foobar cd foobar fedpkg switch-branch f16 git reset --hard 0123abcd fedpkg scratch-build
The URL that comes back to your console is the task for that build, and you can use that to drill down into the individual package build tasks as needed later. Remember, scratch builds are not retained for very long, so if you want the package, try to download it relatively soon after you build it.
Here’s another hint: the git reset command above rewrites your index and your working tree, so essentially you “lose” the later history of the repository. However, git is so awesome that this is not a permanent condition. If you really need to reset the git repository back to its original path, you can use git reflog to find the reference to the checkout you did of the “f16” branch, and reset to it (probably something like this):
git reset --hard HEAD@{1}
Once again, it’s important to point out that the above is not for the faint of heart. If you don’t understand the ramifications of trying withdrawn, obsolete, or deleted packages on your Fedora machine, or packages intended for testing, don’t use them. That being said, testing packages is a really helpful activity, and there are all sorts of easy ways to keep testing contained on your system, such as using virtual guest machines. So the intrepid needn’t be shy!
There’s an even easier way, if you go into the task for the build in koji there’s a source: field (eg //koji.fedoraproject.org/koji/taskinfo?taskID=3557265) that gives you the git url that koji used to generate the build. Without even checking out the package you can just do “koji build –scratch f16 git://pkgs.fedorspro….. ” and it will build that package for you and just sort out all the git side so you don’t need to even check the package out, of course all the same caveats apply as it builds it based on the current fXX-build repository.
@Peter, what an excellent tip! Thanks.