## Using git and github for course assignments

Here’s my tested plan for using git and github to manage student assignments for my upcoming course.

## Initial setup as the instructor:

We’re going to create a student repo and an instructor fork for each assignment. The motivation for separating assignments is to ensure that the diffs that students are submitting for their solutions are tidy. In my case, there’s not much shared code between assignments

Create public* repo that students will see: test-gp-hw0-student.

If you try to fork this on Github, it will tell you that you already have a fork. So instead trick github into forking it via the github importer, import test-gp-hw0-student as a private test-gp-hw0-instructor. Now you have two repos. We’ll set up a branch on test-gp-hw0-instructor to track test-gp-hw0-student for easy merging:

INSTRUCTOR_REPO=test-gp-hw0-instructor
STUDENT_REPO=test-gp-hw0-student
git clone https://github.com/alecjacobson/$INSTRUCTOR_REPO.git cd$INSTRUCTOR_REPO
git remote add student https://github.com/alecjacobson/$STUDENT_REPO.git git fetch student git checkout -b student-tracker --track student/master git checkout master cd ..  To test this out, let’s create a file visible to everyone (students and instructors) in the student repo: git clone https://github.com/alecjacobson/$STUDENT_REPO.git
cd $STUDENT_REPO echo "visible to everyone" >> hello-everyone.md git add hello-everyone.md git commit -m "add file visible to everyone" hello-everyone.md git push cd ../  Now, let’s merge change into the instructor repo cd$INSTRUCTOR_REPO
git checkout master
git pull student master
cat hello-everyone.md
cd ..


Just to be thorough, let’s try the reverse: creating a file just visible to instructors:

cd stewartdent
git remote add instructor https://stewartdent@github.com/alecjacobson/$INSTRUCTOR_REPO.git git fetch instructor  You should see an error: remote: Repository not found. fatal: repository 'https://stewartdent@github.com/alecjacobson/test-gp-hw0-instructor.git/' not found  Now, let’s act as the student to submit the homework # cd stewartdent echo "stewartdent was here" >> assignment-01.md git add assignment-01.md git commit -m "Stewart Dent's Assignment 01 submission" assignment-01.md git push cd ..  The student has pushed their submission onto their own repo. They can continue to work on it using git in all its glory. When they’re down they “hand in” their homework via a pull request onto the public test-gp-hw0-student repo. The student does this by visiting the Github page for their own fork of test-gp-hw0-student and clicking “New Pull Request”. ## Grading as the instructor The instructor can now grade this. I’m imagining that the test-gp-hw0-instructor repo has a solution that can be compared (in some way or another) to the students work. To pull the students work into the instructor copy (but never merge): cd$INSTRUCTOR_REPO
git checkout -b stewartdent-master master
git pull https://github.com/stewartdent/test-gp-hw0-student.git master
cat empty-form.md
git checkout master
git branch -D stewartdent-master


Then the instructor can close the pull request on test-gp-hw0-student.

## Other perks

Questions or discussions related to the homework can be conducted on the “issues” page of test-gp-hw0-student

* The fact that this repo is public should immediately indicate that student’s work submitted via pull request will also be public and importantly will be visible to other students. Unlike the most common form of cheating, this means that Student A can copy the work of Student B without the explicit consent of Student B. Student B’s only possible defense against this would be to submit their work just before the deadline. As far as I know, I can’t hide pull requests from the public (that would be a nice solution) and I prefer not to use any method that relies on student’s having to create a private fork (since they cost money; although, other class require very over-priced textbooks, so a 6-month github subscription is not so crazy, but it does go against the open-source spirit; there’s also the Big Tobacco style get’em while their young https://education.github.com/pack).

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