Git in CS 225

Overview

git will be used 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.
• Submission of your code.

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 good practices are used. The following is a brief list of good version control practices:

• 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.

Again, the above practices are not hard and fast, nor complete, but they should help you complete your MPs and future coding projects should you use git for them as well.

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, code will be released to release and you will merge it into your repository to get the initial code. You’ll then complete the MP or lab and then commit your code to your repository. We will view the latest submission you made before the due date to grade 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 225 repository this semester, you will need to have a CS 225 repository set up for you. This process is simple:

1. Visit https://edu.cs.illinois.edu/create-ghe-repo/cs225-sp20/.
2. When you view your repostiory, do not follow the instructions to create a README. Instead, just note the URL – it will be similar to https://github-dev.cs.illinois.edu/cs225-sp20/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 comptuer.

The URL of your repository will be based on your NetID and you will need to replace NETID with your NetID.

To clone your repository, run git clone:

git clone https://github-dev.cs.illinois.edu/cs225-sp20/NETID.git cs225git

…you can replace cs225git with whatever folder you want created. For example, you may want to call your folder just “cs225” or anything else.

Finally, move into the directory you just cloned:

cd cs225git

[Optional] Store your git credentials once and for all

Run the following command so that you only have to type in your git credentials once.

git config credential.helper store

Add the release repository as a remote

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

git remote add release https://github-dev.cs.illinois.edu/cs225-sp20/_release.git

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 225, you need to fetch and merge the release repository into your repository. This can be done with two commands:

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

Don’t type LAB_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/LAB_NAME --allow-unrelated-histories

Assignment Submission (do this often!)

Every time you want to submit work, you will need to add, commit, and push your work to your git repository. This can always be done using the following commands on a command line while within your CS 225 directory:

git add -u
git commit -m "REPLACE THIS WITH YOUR COMMIT MESSAGE"
git push origin master

You should substitute "REPLACE THIS WITH YOUR COMMIT MESSAGE" with a short message describing what you did since the commit. This will help both you and course staff understand what you did in a specific commit.

Some examples of “good” commit messages:

• “Fix the segfault in the maze destructor”
• “Implement the reverse helper function”
• “Refactor duplicate code into helper method”

Some examples of bad commit messages:

• “REPLACE THIS WITH YOUR COMMIT MESSAGE”
• “file submission”
• “commit”
• “HAAAAAAAAAAANDS”

Verify your Submission

You can always verify your submission by visiting https://github-dev.cs.illinois.edu/ and viewing the files in your repository. Only the files that appear on the master branch of your github-dev repository will be graded.