Introduction
Git basics are very straightforward, but it sometimes feels like a bottomless pit when you find yourself on the wrong side of a confusing error situation. It’s doubly frustrating because you think that messing up or trying the wrong solution can lose data. It’s actually very hard to “lose” data with Git but it can certainly be hiding somewhere you wouldn’t think to look without an experienced dev poking around.
The thing about Git is that, unless you’ve got a seriously impressive memory, you can’t just master it by reading about it; you need hands-on practice! For example, find a problem you want to fix, run into a merge error, and then dive into Google to learn a new Git technique along the way to help you fix that problem.
To help you out, come back and refer to this lesson again when you’re in trouble. We’ll first cover a real-world example of a GitHub workflow used on this very project. The Additional Resources section below should also help you find high quality resources for when you need them later on.
Lesson overview
This section contains a general overview of topics that you will learn in this lesson.
- A reminder about commit messages.
- Using Git to make open source contributions.
Commit messages for collaboration
Before we dive into workflows, take a minute to remind yourself about good commit messages. You can check the Commit Messages lesson for a reminder. This is a good time to draw particular attention to Conventional Commits, a standard for commits that is gaining more and more popularity for collaborative projects. It helps to make sure your commit message gives a clear description of its purpose to anyone reading. Going forward, you may like to implement these (if you aren’t already!), or at least be aware of them for when you read other repos.
Assignment
Let’s say you want to contribute to our curriculum repo.
How do you contribute when you do not have write access to the repository? Below is a production-ready workflow that is actually used by contributors to this website. We’ll assume here that you have commented on an open issue on our repo and that it has been assigned to you. If you don’t have an issue assigned to you, you can still follow along with some arbitrary updates, just stop before step 3 in the Sending your pull request section since your changes aren’t legitimate.
The key players in this story will be the upstream
(the original GitHub repository), the origin
(your fork of that repo), and the “local” repository (your local clone of origin
). Think of it as a happy triangle… except that “local” can only pull from upstream
, not push.
Initial setup
- Read the TOP contributing guide for the project.
- Navigate to the curriculum repository and fork the original (“upstream”) repository into your own GitHub account by using the “fork” button at the top of that repo’s page on GitHub.
- Clone your forked repository onto your local machine using something like
git clone git@github.com:your_user_name_here/curriculum.git
(you can get the url from the little widget on the sidebar on the right of that repo’s page on GitHub). - Because you cloned the repository, you’ve already got a remote that points to
origin
, which is your fork on GitHub. You will use this to push changes back up to GitHub. You’ll also want to be able to pull directly from the original repository on GitHub, which we’ll callupstream
, by setting it up as another remote. Do this by using the git command below inside the project foldercurriculum
:
git remote add upstream git@github.com:TheOdinProject/curriculum.git
Ongoing workflow
We’ve got one main branch – main
. main
is for production-ready code. Any code deployed to main
(on the original repo, not on your fork) will be tested in staging and shipped to production. You’ll be working in a feature branch and submitting your pull requests to the main
branch.
- Create a new feature branch for whatever feature you want to build, and add commits following the same practices that you learned about in the branching section of our Revisiting Rock Paper Scissors lesson.
- When you’re done with your feature, odds are that someone has made changes to the upstream repository in the meantime. That means that your
main
branch is probably out of date. Fetch the most updated copy usinggit fetch upstream
. - Now merge the upstream’s changes into your local version of
main
usinggit merge
. Specifically, you’ll first want to make sure you’re on yourmain
branch usinggit checkout main
and thengit merge upstream/main
to merge in those upstream changes that we just fetched. - Now that your
main
branch is up-to-date with upstream, you need to merge it into your feature branch. Yes, that is correct and it seems odd at first. Don’t you want to merge the feature branch into themain
branch instead? Yes, you do, but not yet. Your feature branch is dirty. You don’t know if it has any conflicts which might creep up. Any time you are merging in more “senior” branches (e.g. merging the feature intomain
), you want it to be a clean and conflict-free merge if possible. So you first merge the “senior” branch into your dirty branch to resolve those conflicts. Rungit checkout your_feature_name
to jump back onto your feature branch, thengit merge main
to mergemain
into it. - You may have merge conflicts… resolve those using the skills you learned in the Working with Remotes lesson!
Note that a git fetch upstream
followed by a git merge upstream/some_branch
is the EXACT same thing as doing a git pull upstream some_branch
. We prefer to split it up here so that we can explicitly walk through the steps.
Sending your pull request
- Now that your feature branch is squeaky clean and you know it’ll merge cleanly into
main
, the hard part is all over. All that’s left is to make the Pull Request (often abbreviated as PR) against ourupstream
repo on GitHub! - Now you want to send your feature branch back up to your
origin
(your fork of theupstream
repository). You can’t send directly toupstream
because you don’t have access, so you’ll need to make a pull request. Usegit push origin your_feature_name
to ship your feature branch up to your fork on GitHub. - If you have been following along with the above steps to get familiar with this workflow, you should stop at this point. If you have completed an assigned issue, the final step is to submit a pull request to merge your feature branch into the original
upstream
repository’smain
branch. This can be done using GitHub’s interface. - Shake your moneymaker, you’re an OSS contributor!
Knowledge check
The following questions are an opportunity to reflect on key topics in this lesson. If you can’t answer a question, click on it to review the material, but keep in mind you are not expected to memorize or master this knowledge.
Additional resources
This section contains helpful links to related content. It isn’t required, so consider it supplemental.
- Seth Robertson’s Git Best Practices
- Learn about Git Branching from Peter Cottle using his interactive branching tutorial.
- Dangit, Git!?! is a quick reference to get you out of common Git problems.
- This article on How to undo (almost) anything with Git will walk you through some of many options Git provides for undoing various mistakes.