Information about git commands for contributing to other repositories

[bvssvni]

1. Fork the repository by clicking the 'Fork' button on Github. This will copy the repository to your own Github account.
2. Clone your repository to local hard drive. This is the same as when creating a new repository on Github and starting to work on it locally.
3. Add 'upstream' remote with the command:

git remote add upstream <url>

The upstream remote should point to the original repository which you like to contribute to. After you do local commits you can pull from upstream with the command

git pull --rebase upstream master

This will update your master with commits from upstream and then apply your commits on top of them. Now you can push to your Github fork and then send a pull request.

git reset --soft upstream/master

This will merge your commits and open them for editing so you can write a new commit message.

Squashing commits

If you need to squash the last 2 commits, you write:

git reset --hard HEAD~2
git merge --squash HEAD@{1}

Then you can write a new commit message.
If you get a conflict when trying to merge, you can use:

git push --force origin master

[bvssvni]

The following command can be used to create a new branch with the updates from upstream by replacing the text <new branch name> with a description of what you are working on:

git fetch upstream master && git checkout upstream/master && git checkout -b <new branch name>

[bvssvni]

Some commands that reduces many merge commits:

git fetch upstream; git rebase upstream/master

git pull --ff-only upstream master

[HayleyDeckers]

Question: Should collaborators accept their own pull requests, or should this be left up to the maintainers of each individual repo?

[bvssvni]

@RDeckers Self merge is encouraged, assuming you know what you are doing, see PistonDevelopers/piston#674