Adding patches to Rails now that it's on git

May 1, 2008 core rails

This blog post was written in 2008. Information and links in this post may be outdated.

It took me a while to figure out how to try to contribute to Rails now that it's on Lighthouse / Github. Here's what I do now, and it seems to work:

First, create a clone of the main git repository (not your fork of it - there's really no reason to fork unless you want others to pull your changes before core accepts them):

Setup your development directories

mkdir rails
cd rails
mkdir patches
git clone git://github.com/rails/rails.git source

Now you have:

rails
|--patches
`--source

Set up your dev branch

Then create a new branch where you'll store just the changes you make for this patch:

git checkout -b your_patch_name master

Create the patch

Make your test-driven changes and when you are ready to create the patch run:

git diff -p master > ../patches/your_patch_name.patch

Setup a throwaway test branch

If you want to test your change

create a new branch and apply the patch (this is useful if other commits have happened since you first created your patch)
run the tests and make sure that everything passes
clear your changes and delete the test branch

git checkout master git pull git checkout -b your_patch_name_test master git apply ../patches/your_patch_name.patch git stash ... git checkout master git stash clear git branch -D your_patch_name

Using git stash allows you to move back to the master branch without taking your changes with you - leaving you with a clean master branch. To learn more about git stash syntax, see the git documentation

Continue development

When it's time to update the code you put in the patch, you can just rebase from the master branch:

git co your_patch_name
git rebase master

Then you can fix whatever changes you need to fix and recreate your patch (or create a new one if your old changes were accepted).

Share you patch

The next step is to go to http://rails.lighthouseapp.com/ and create a ticket. Make sure that you

tag it with "patch" as well as whatever else it applies to
don't forget to upload the patch itself.

When you upload, it appear in the middle of the right-hand column as a blue link - it's hard to find, so look carefully. Then get as many people as possible to grab your changes and test them and add +1's where necessary.

Summary

When all is said and done you are left with a directory full of patches you can apply, a clean master working copy and individual branches for all of your patches that you can maintain over time. While this was possible with subversion, it's way cleaner with git. Contributing to rails is easier than ever!