Locate the section for your github remote in the .git/config
file. It looks like this:
[remote "upstream"]
url = https://github.com/chrismckelt/webminder.git
fetch = +refs/heads/*:refs/remotes/upstream/*
Now add the line fetch = +refs/pull/*/head:refs/remotes/$$$$$$$$/pr/*
to this section. Obviously, change the github url to match your project's URL. It ends up looking like this:
$$$$ = origin or upstream
[remote "upstream"]
url = https://github.com/chrismckelt/webminder.git
fetch = +refs/heads/*:refs/remotes/upstream/*
fetch = +refs/pull/*/head:refs/remotes/upstream/pull/*
Now fetch all the pull requests:
$ git fetch origin
* [new ref] refs/pull/1000/head -> origin/pr/1000
* [new ref] refs/pull/1002/head -> origin/pr/1002
* [new ref] refs/pull/1004/head -> origin/pr/1004
* [new ref] refs/pull/1009/head -> origin/pr/1009
...
To check out a particular pull request:
$ git checkout pr/999
Branch pr/999 set up to track remote branch pr/999 from origin.
Switched to a new branch 'pr/999'