Setting up Your Git Repository

We will use git throughout this semester as the version control system for MPs and labs. Specifically, we will be using git for two functions:

• Distribution of provided code.
• Distribution of grades.

You will not use git for turning things in; you will use Prairielearn for that.

While we do not require that you learn and use good version control practices, we cannot stress enough how useful a good version control system can be when you follow good practices. For example:

• Always use a good commit message which describes the changes in the commit.
• Never check in broken code. (This is more important when working in groups, but still good practice.)
• Commit regularly and frequently. For example, commit when you’re done writing a function. This allows both simpler commit messages and greater confidence in the repository.

We will assume that you know how to use the basic git commands, but we don’t expect you to be an expert.

Setting up git

There are two repositories that you’ll be interacting with as part of this course:

1. Your personal course repository
2. The release repository (release)

In general, we will release code to release and you will merge it into your repository to get the initial code. You’ll then complete the MP or lab in your personal repository. While we won’t use the repository for grading, it does make it easy for us to look at your files if you are trying to get help on something, and it also makes a good backup of your work.

To get everything set up, there are certain things you will need to setup once the entire time you’re in the course, things you need to setup once per computer you use, and things you need to do once per MP.

Course Setup (necessary only once for the entire semester)

The first time you’re accessing the CS 421 repository this semester, you will need to have a CS 421 repository set up for you. This process is simple:

1. If you don’t have one already, create an account at github.com.
   1. Once you do this, you will need to create a personal access token
   2. Next, you will need to authorize the token for single sign on (SSO)
2. Visit this magic repository creator
3. It will ask you to join the illinois-cs-coursework group.
4. You will get a repository with a URL like https://github.com/illinois-cs-coursework/sp22_cs421_NETID, where NETID is your actual netid.

Workspace Setup (necessary only once per computer/directory you use)

Create a clone of your repository

To setup your computer to work on an MP or a lab, you will need to clone your repository onto your computer.

To clone your repository, run git clone:

git clone https://github.com/illinois-cs-coursework/sp22_cs421_NETID.git cs421git

you can replace cs421git with whatever folder you want created. For example, you may want to call your folder just “cs421” or “cs421work” or anything else.

Cloning into 'sp22_cs421_NETID'...
remote: The `illinois-cs-coursework' organization has enabled or enforced SAML SSO. To access
remote: this repository, visit https://github.com/orgs/illinois-cs-coursework/sso?authorization_request=someverylongstringofletters
remote: and try your request again.

Finally, move into the directory you just cloned:

cd cs421git

Add the release repository as a remote

To connect to the release repository, you need to add a remote:

git remote add https://github.com/illinois-cs-coursework/sp22_cs421_.release.git

Note the extra period. If we don’t put that there, one day some poor student will get the netid release and all Java will break loose.

You’re now all set to begin to work on an assignment! :)

Assignment Setup (necessary only once per assignment)

To retrieve the latest assignments for CS 421, you need to fetch and merge the _release repository into your repository. You can do this with two commands:

git fetch release
git merge release/MP_NAME -m "Merging release repository"

Don’t type MP_NAME literally here; on each lab we will provide the proper name to use.

If git happens to complain about unrelated histories, use this command:

git merge release/MP_NAME --allow-unrelated-histories

Assignment Submission (do this often!)

Well.. you aren’t actually submitting anything. But a remote git repository serves as a wonderful backup tool. If something goes wrong and you delete your local copy, you can always restore it from the remote repository.

Every time you reach a milestone and want to checkpoint your work, you will need to add, commit, and push your work to your git repository. Here are the commands to do that, assuming you are in your CS 421 repository:

git add -u
git commit -m "file submission"
git push origin master

Sites like GitHub are migrating away from naming the main branch master, preferring instead to call it main instead. In that case, type git push origin main.

Verify your Submission

You can always verify your “submission” by visiting https://github.com/ and viewing the files in your repository.

Grades

To submit grade reports to you, we will create a branch in your repository called grades. In that branch will be a directory called, you guessed it, grades, and usually a file grade-report.txt. It will be a few weeks before the first one shows up, so don’t worry if it’s not there yet. We will post to campuswire when that happens.

It is better if you do not try to switch into that branch. It sometimes happens that a student does this and then modifies the grade report file. This will break the script that sends out grade reports, and you will no longer get updates until the course staff can fix it.

To view your grades, do a git fetch followed by a git merge grades to merge the files into your main branch.