Repositories for Private Development of Public Course Content

For course material development, some content such as homework solutions need to be kept private (at least temporarily). This note explains how two repositories can be used in concert to simplify private development of public course content.

The material on this page has been adopted and expanded from this posting

Initial setup

Remote Public and Private Repositories

Suppose you have two Github repositories:

• Public repo is at https://github.com/username/public-repo.git
• Private repo is at https://github.com/username/private-repo.git

The public repo will be open to the students, whereas the private repo will be used for development and testing (shared with TAs etc.)

Local Repository with Public and Private Remotes

Create a local repository and set target repositories

mkdir ~/local-repo && cd ~/local-repo
git init
git remote add public https://github.com/username/public-repo.git
git remote add private https://github.com/username/private-repo.git

Add first public file in master branch and push to public-repo:

# cd ~/local-repo && git checkout master

echo "README" >> README.md
git add README.md
git commit -m"first commit"

git push public master
git push private master

Now, public-repo/master and private-repo/master on Github are identical.

Create a local development branch: private-branch

# cd ~/local-repo && git checkout master
git checkout -b private-branch

echo "handout" > homework1-handout.md
echo "solutions" > homework1-solution.md
git add homework1-handout.md homework1-solution.md 
git commit -m"private development"

git push -u private private-branch

Here private-branch branch syncs with private-repo/private-branch (remote branch name defaults to private-branch)

Publishing content to public repository

Do not merge but checkout relevant files into public-repo/master:

# cd ~/public-repo && git checkout master

git checkout private-branch homework1-handout.md
git add homework1-handout.md
git commit -m"release homework1"
git push

Note the line git checkout private-branch homework1-handout.md overwrites (or creates) homework1-handout.md in public-repo/master.

Using different remote vs. local branch names (Optional)

A local branch (you would like to keep private) can have any name. For example, create a local branch named new-branch to sync with private-repo/private-branch:

# cd ~/public-repo && git checkout master

git checkout --orphan new-branch
git pull private private-branch
# make some changes
git push private new-branch:private-branch

Any changes in new-branch branch will now push to private-repo/private-branch.

Note: upstream tracking doesn’t seem to stick with ‘-u’.

Setting default push behavior (Optional)

To me, the default behaviors of git pull and git push are strange. I kept on using git push [remote] [branch] above because even setting upstream with -u does not behave as I expect it to.

However, configuring git config push.default upstream seems much more intuitive to me.

Also, forcing checkout seems to simplify the process of cloning private/feature to a new local branch and sets the upstream:

git config push.default upstream --local
git checkout -f -b new-branch private/feature
echo "fix problems" >> homework1-handout.md
git add -u
git commit -m"fix homework1-handout"
git push -v

Above will push our local new-branch to private/feature branch.

Duplicating Dual Remote Setup

Clone public repository and add private repository as remote:

git clone https://github.com/username/public-repo.git ~/public-repo
cd ~/public-repo

# set local master branch to track public master branch
git remote rm origin # to explicitly differentiate public vs private repos
git remote add public https://github.com/username/public-repo.git
git push -u public master 

Sync a local private-branch with private-repo/private-branch:

# cd ~/public-repo && git checkout master

git checkout --orphan private-branch 

git remote add private https://github.com/username/private-repo.git
git pull private private-branch

echo "add solutions" >> homework1-solution.md
git add -u
git commit -m"modify homework 1 solution"

git push -u private private-branch

Check pushing is setup properly with a dry run: git push -n -v

Adding Branches

If multiple people are working on this repository, multiple branches need to be created. To create additional branches to the private repository, simply create a branch from private-branch:

# cd ~/public-repo && git checkout private-branch

git checkout -b new-private-branch
echo "newfile" > newfile.txt
git add newfile.txt
git commit -m'adding a new file'

git remote add private new-private-branch
git push --set-upstream private new-private-branch