Collaborating

Last updated on 2025-07-01 | Edit this page

Overview

Questions

  • How do I collaborate with others using Git?
  • What different models exist for Git collaboration?
  • What are protected branches, and how do I handle merge conflicts?

Objectives

  • Describe multiple models of collaboration using Git
  • Demonstrate how to add collaborators and manage permissions in GitLab
  • Practice cloning, committing, and pushing to a shared repository
  • Understand how to resolve common issues like push rejections and merge conflicts

Collaborating with Git

One of Git’s most powerful features is that it makes collaboration straightforward and trackable. When working with others, a shared repository acts as the single source of truth. Contributors clone, modify, and then sync their work using version control commands like pull, commit, and push.

Different Models for Collaboration

There are several ways to collaborate using Git:

  • Shared repository model: You give collaborators direct access to your repository. This is quick but requires trust.

  • Fork-and-pull model: A collaborator creates a copy (fork) of your repository, makes changes, and submits a merge request (also called a pull request). This is commonly used in open-source projects. It may not work between two private repositories.

For this exercise, we assume a shared repository trust model. That means you’ll work directly in each other’s repositories.

We’ll now walk through the process of adding a collaborator and working on the same project together.

Step 1: Pair Up and Add a Collaborator

You will work in pairs. First:

  • Introduce yourselves.
  • Person 1: Get the UUN (University User Name) of Person 2.

Add Member to Your Repository

Person 1 should add Person 2 as a collaborator on their GitLab repository:

  1. Click Invite members.
  2. Enter Person 2’s UUN.
  3. Set the role to Developer.
  4. Go to the sidebar and click Project → Members.
  5. Confirm the role is set correctly.
Add members in GitLab
Add members in GitLab
Adjust permissions
Adjust permissions

Step 2: Unprotect the Branch

In GitLab, branches can be protected to restrict who can push to them. To allow collaborators to push changes, you need to modify this setting:

  • Go to Settings -> Repository -> Protected Branches.
  • Find the main branch (or master depending on your setup).
  • Click Unprotect.
Unprotect branch
Unprotect branch

Step 3: Clone the Repository

What if you were given a link to a folder from a remote location that you needed to get on your computer? How would you do that? You’d need to make a copy of the remote repository to your local machine. In the world of Git, this is referred to as “cloning.” The command for cloning is, you guessed it, git clone.

Person 2 now clones the repository on their system (e.g., on Eddie):

BASH 

git clone https://git.ecdf.ed.ac.uk/<person1>/myproject.git project-collab
cd project-collab
git remote -v

This creates a local copy of the repository and shows the remote repository settings.

Clone repo
Clone repo

Step 4: Check Who Edited What

Git provides the blame command to show who last modified each line of a file:

BASH 

git blame README.md

This is useful when debugging or understanding the origin of changes.

Step 5: Make a Change and Commit

Person 2 can now make a change to the README.md file:

BASH 

nano README.md  # or use any editor

After saving the file:

BASH 

git add README.md
git commit -m "Update README.md with message from Person 2"

Step 6: Push the Changes

Now attempt to push:

BASH 

git push

Rejected?

If you see a “rejected” message, this likely means your local copy is behind the remote. You need to pull the latest changes:

BASH 

git pull

Then resolve any conflicts if necessary and try pushing again.

Merge Conflicts

Sometimes two collaborators edit the same part of a file. This creates a merge conflict.

Git will mark the conflict like this:

Merge conflict example
Merge conflict example

You must manually edit the file to resolve the conflict, then:

BASH 

git add filename
git commit -m "Resolve conflict in filename"
git push

Optional: Cache Your Credentials

If you’re prompted for your credentials too often, you can cache them temporarily:

BASH 

git config --global credential.helper 'cache --timeout=3600'

This caches your credentials for one hour.

Key Points

  • Git allows multiple collaboration models; shared access is fastest but requires trust.
  • GitLab permissions and protected branches must be configured for collaborators.
  • Always pull before pushing to avoid rejection.
  • Merge conflicts are normal and can be resolved with manual editing.