Advanced git

Block 2.1: Collaboration & Merge Requests

Jan Simson

What is GitLab?

• GitLab is a FOSS project to host your own website for git repositories
• GitLab.com is their SaaS offering
• By having your git repository online, you can easily collaborate with others
• There are many other similar, alternative websites
  • Codeberg 🇩🇪
  • GitHub
  • Bitbucket
  • … (and many more)
• Together they contain the majority of the world’s software

Why use a Website?

• Backup of your project
• Collaboration
  • Not just with people you know
• Free and Open-Source Software (FOSS)
• Visibility

Connecting git and GitLab

Authenticating with GitLab.com 🗝️

• We will use a guide to set up the authentication with GitHub
• Please go to the website and follow the steps to authenticate with GitHub
• A PDF version of the guide can be found here

https://simson.io/advanced-git/output/resources/ssh/how-to-setup-gitlab-ssh.html

Remotes

Background: https://unsplash.com/photos/EOQhsfFBhRk

Remotes

• Link to a remote repository on a hosting website
• There can be more than one remote, but it is uncommon
• Just like your repository, the remote repository also has branches
• The default name for a remote is origin
  • When you clone a repository, this remote is already linked

Adding a Remote

When you want to add an existing repository to github, you will have to add the remote yourself

git remote add <remote name> <remote URL>

For example:

git remote add origin git@github.com:jansim/intro-to-git.git

To learn about all possible commands for remotes use -h

git remote -h

Syncing Changes: Overview

You first pull the latest changes from the remote and then push your own changes

Getting Changes: git pull

• You can retrieve the latest changes from github by running git pull
• This fetches the latest changes and merges them into your current branch
• Typically your local branch is set up to track a remote branch with the same name
  • If not, you get a warning from git

# Pull from the tracked remote branch
git pull

# Pull from a specific branch
git pull <remote>/<branch>

Getting Changes: git pull

• This fetches the latest changes and merges them into your current branch
  • git pull really does two things here
• You can also run git fetch to fetch the latest changes and then git merge <remote>/branch to merge them
• git fetch will always fetch the latest changes without doing anything with them (which can be useful)

Pushing Your Changes: git push

• You can send your changes to github by running git push
• This only works if there are no new changes at the remote
  • If there have been changes since your last pull you need to pull again

# Push to the tracked remote branch
git push

# Push to a specific branch
git push <remote>/<branch>

Pull / Merge Requests

Pull / Merge Requests (PRs / MRs)

• When collaborating with other people, it’s often good to review each other’s changes
• This is easiest done by using pull or merge requests
  • You request for someone to pull your changes
• Terminology
  • GitHub: Pull Requests
  • GitLab: Merge Requests

merge requests: Overview

Overview of the merge requests page in a GitLab repository

Repository: https://gitlab.com/gitlab-org/gitlab

merge requests: Detailed View

View of a single merge request on GitLab

Repository: https://gitlab.com/gitlab-org/gitlab

Why Issues & merge Requests are Necessary

Overview of the issues page of the gitlab repository.

Repository: https://gitlab.com/gitlab-org/gitlab

When Should you start using Issues & MRs?

• Maybe your project doesn’t need these features yet
• Often it makes sense to use PR / MRs even when collaborating with just a few people
  • To avoid merge conflicts
  • Also for reviewing each others changes
• Many companies require code reviews and using MRs

Questions?

Practical: Collaborating via GitLab

1. Fork the Website Template Repository: https://gitlab.com/jansim/website-template
2. Clone your forked repository
3. Add an alumni page by following the instructions in docs/alumni/index.md
4. Push your changes to GitLab and create a MR to add yourself as an alumni

End of Section 🎉

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