Question

I’m new to GIT and GitHub (and Homebrew for that matter); the formula for emacs in the main repository is broken in OS X Lion, but there is a “pull request” (https://github.com/mxcl/homebrew/pull/6518) that fixes the problem (but it isn’t merged in the main repository).

How can I update my local copy of the Homebrew repository to have that formula fixed ? If I manage that, will that formula still be updated if the main repository includes that fix ?

Please correct me if the terminology is not correct.

Answer 1

The documentation on Github describes that quite verbose (section Merging a Pull Request):

on your repo:

git checkout master
git remote add colin https://github.com/ColinHebert/homebrew.git
git fetch colin

Now, you have the full content of the colin repo (including knowledge of the commit hashes used in that repo). Next is to apply the changes. The docs say that you should do a git merge, but that’s not so good in our case since colin added the changes to his master. If he works on master (and does some more commits), you’ll get these changes too.

Fortunately, the four commits making up the patch are named in the Pull-request: ae28b29e, df10b69a, e8915488, 87f2d1e5. You can apply them with git cherry-pick:

git cherry-pick ae28b29e
git cherry-pick df10b69a
git cherry-pick e8915488
git cherry-pick 87f2d1e5

That’s it. You could now delete the remote colin with

git remote rm colin

Another possibility would be to download the patch and apply it:

git checkout master
curl https://github.com/mxcl/homebrew/pull/6518.patch | git am

The patches for pull requests are always available via

https://github.com/<user>/<repo>/pull/<request_number>.patch