Collaborating

Overview

Teaching: 25 min
Exercises: 0 min

Questions

• How can I use version control to collaborate with other people?

Objectives

• Clone a remote repository.

• Collaborate by pushing to a common repository.

• Describe the basic collaborative workflow.

For the next step, get into pairs. One person will be the “Owner” and the other will be the “Collaborator”. The goal is that the Collaborator add changes into the Owner’s repository. We will switch roles at the end, so both persons will play Owner and Collaborator.

Practicing By Yourself

If you’re working through this lesson on your own, you can carry on by opening a second terminal window. This window will represent your partner, working on another computer. You won’t need to give anyone access on GitLab, because both ‘partners’ are you.

The Owner needs to give the Collaborator access. On GitLab, click the Members button on the left, and in the “GitLab member or Email address” field, enter your partner’s DEVELOP GitLab username or associated e-mail address. Assign this person the role of “Maintainer” so that they have full Push/Pull permissions.

Once the Collaborator has been added as a Maintainer project member, the Collaborator should see this new repository listed under “Your Projects.” The Collaborator should also get an e-mail regarding this action, sent to the e-mail address linked to GitLab.

Next, the Collaborator needs to download a copy of the Owner’s repository to her machine. This is called “cloning a repo”.

The Collaborator doesn’t want to overwrite her own version of planets.git, so needs to clone the Owner’s repository to a different location than her own repository with the same name.

To clone the Owner’s repo into her Desktop folder, the Collaborator enters:

$ git clone git@gitlab.developprogram.org:vlad/planets.git ~/Desktop/vlad-planets

Replace ‘vlad’ with the Owner’s username.

The Collaborator can now make a change in her clone of the Owner’s repository, exactly the same way as we’ve been doing before:

$ cd ~/Desktop/vlad-planets
$ nano pluto.txt
$ cat pluto.txt

It is so a planet!

$ git add pluto.txt
$ git commit -m "Add notes about Pluto"

 1 file changed, 1 insertion(+)
 create mode 100644 pluto.txt

Then push the change to the Owner’s repository on GitLab:

$ git push origin main

Enumerating objects: 4, done.
Counting objects: 4, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 306 bytes, done.
Total 3 (delta 0), reused 0 (delta 0)
To git@gitlab.developprogram.org:vlad/planets.git
   9272da5..29aba7c  master -> master

Note that we didn’t have to create a remote called origin: Git uses this name by default when we clone a repository. (This is why origin was a sensible choice earlier when we were setting up remotes by hand.)

Take a look at the Owner’s repository on GitHub again, and you should be able to see the new commit made by the Collaborator. You may need to refresh your browser to see the new commit.

Some more about remotes

In this episode and the previous one, our local repository has had a single “remote”, called origin. A remote is a copy of the repository that is hosted somewhere else, that we can push to and pull from, and there’s no reason that you have to work with only one. For example, on some large projects you might have your own copy in your own GitLab account (you’d probably call this origin) and also the main “upstream” project repository (let’s call this upstream for the sake of examples). You would pull from upstream from time to time to get the latest updates that other people have committed.

Remember that the name you give to a remote only exists locally. It’s an alias that you choose - whether origin, or upstream, or fred - and not something intrinstic to the remote repository.

The git remote family of commands is used to set up and alter the remotes associated with a repository. Here are some of the most useful ones:

• git remote -v lists all the remotes that are configured (we already used this in the last episode)
• git remote add [name] [url] is used to add a new remote
• git remote remove [name] removes a remote. Note that it doesn’t affect the remote repository at all - it just removes the link to it from the local repo.
• git remote set-url [name] [newurl] changes the URL that is associated with the remote. This is useful if it has moved, e.g. to a different GitLab account, or from GitLab to a different hosting service. Or, if we made a typo when adding it!
• git remote rename [oldname] [newname] changes the local alias by which a remote is known - its name. For example, one could use this to change upstream to fred.

Take a look to the Owner’s repository on its GitLab website now (maybe you need to refresh your browser.) You should be able to see the new commit made by the Collaborator.

To download the Collaborator’s changes from GitLab, the Owner now enters:

$ git pull origin main

remote: Enumerating objects: 4, done.
remote: Counting objects: 100% (4/4), done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 3 (delta 0), pack-reused 0
Unpacking objects: 100% (3/3), done.
From git@gitlab.developprogram.org:vlad/planets
 * branch            main     -> FETCH_HEAD
   9272da5..29aba7c  main     -> origin/main
Updating 9272da5..29aba7c
Fast-forward
 pluto.txt | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 pluto.txt

Now the three repositories (Owner’s local, Collaborator’s local, and Owner’s on GitLab) are back in sync.

A Basic Collaborative Workflow

In practice, it is good to be sure that you have an updated version of the repository you are collaborating on, so you should git pull before making our changes. The basic collaborative workflow would be:

• update your local repo with git pull origin main,
• make your changes and stage them with git add,
• commit your changes with git commit -m, and
• upload the changes to GitLab with git push origin main

It is better to make many commits with smaller changes rather than of one commit with massive changes: small commits are easier to read and review.

Switch Roles and Repeat

Switch roles and repeat the whole process.

Review Changes

The Owner pushed commits to the repository without giving any information to the Collaborator. How can the Collaborator find out what has changed with command line? And on GitLab?

Solution

On the command line, the Collaborator can use git fetch origin main to get the remote changes into the local repository, but without merging them. Then by running git diff main origin/main the Collaborator will see the changes output in the terminal.

On GitLab, the Collaborator can go to the repository and click on “commits” to view the most recent commits pushed to the repository.

Comment Changes in GitLab

The Collaborator has some questions about one line change made by the Owner and has some suggestions to propose.

With GitLab, it is possible to comment the diff of a commit. Over the line of code to comment, a blue comment icon appears to open a comment window.

The Collaborator posts its comments and suggestions using GitLab interface.

Version History, Backup, and Version Control

Some backup software can keep a history of the versions of your files. They also allows you to recover specific versions. How is this functionality different from version control? What are some of the benefits of using version control, Git and GitLab?

Key Points

• git clone copies a remote repository to create a local repository with a remote called origin automatically set up.