Checkout a GitHub Pull Request

If you work with a lot of open source projects, you may find a need to modify a GitHub Pull Request before merging to the master branch. This may be because you need to rebase, fix a failing test, or resolve a merge conflict caused by an upstream change.

If you have used the hub gem before, you are probably familiar with the following code:

$ hub checkout https://github.com/sethvargo/chefspec/pull/1 custom-branch

But hub has some drawbacks, mainly that it is "yet another thing" you need to install and understand. Thankfully, GitHub provides an easy way to checkout a remote Pull Request just using Git!

From inside the root of your repository, run the following command, replacing $NUMBER with the Pull Request number:

$ git fetch origin pull/$NUMBER/head:pr-$NUMBER

This will create a new branch named pr-$NUMBER. You can then checkout the branch:

$ git checkout pr-$NUMBER

This can easily be converted into a shell function:

checkout-pr () {
  git fetch origin pull/$1/head:pr-$1 && git checkout pr-$1;
}

You could then use this shell function to checkout a PR:

$ checkout-pr 123

But it seems like this should be a Git command... You can wrap the whole thing up in a Git alias:

[alias]
  pr = "!f() { git fetch origin pull/$1/head:pr-$1 && git checkout pr-$1; }; f"

Now, when you want to checkout a remote GitHub Pull Request, simply run the following command:

$ git pr NUMBER

I have been using this alias for over a year now, and I absolutely love it. I hope you find it useful too!