Clone & Fork¶

When starting collaboration on an existing project, you need a way to tell Git where the remote repository you want to collaborate on resides, and you need to get a local copy of said codebase to work on for yourself. There are two ways to do this: cloning the repository, or forking the repository.

Cloning¶

The git clone command is perhaps the most well-known. This command allows you to reflect (i.e. make a copy) the repository, in its current state, locally. Moreover, this automatically registers this source repository as the remote repository within Git. This will enable you to git fetch commits and branches (retrieve changes made by others) from the remote repository, and git push (submit your own changes and branches) to this remote repository.

For example, I frequently contribute to open-source development projects, such as PyTorch: a popular deep learning framework. If you would want to do that as well, you would start by cloning the repository:

# Navigate to the directory you want to store the cloned repository
cd ~/coding/python

# Clone the Pytorch repository
git clone https://github.com/pytorch/pytorch

# Change directory to the repository
cd pytorch

As visualised below, this workflow enables multiple developers to work on the same project (repository) at the same time.

flowchart TB
  R[(Remote<br />Repository)] <-. Push/Pull .-> C_1(<b>Clone</b><br/>Developer 1)
  R <-. Push/Pull .-> C_2(<b>Clone</b><br/>Developer 2)
  R <-. Push/Pull .-> C_3(<b>Clone</b><br/>Developer 3)

Forking¶

Forking a repository is a similar concept to cloning, but there a some differences.

When using git clone, you copy the entire repository, along with its ties to the remote location, thus enabling you to git fetch from it and git push to it. A fork only copies the repository, but creates an entirely new and separated codebase. There is no synchronisation between your fork and the original repository, in the sense that you could push to it, or pull from it, as you would have been able to when cloning. In Git terms: It does not register the source as a remote repository for your local repository.

flowchart TD
  R[(Project<br />Repository)] <-. Push/Pull ..-> C_1(<b>Clone</b><br/>Developer 1)
  R <-. Push/Pull ..-> C_2(<b>Clone</b><br/>Developer 2)
  R <-. Push/Pull ..-> C_3(<b>Clone</b><br/>Developer 3)
  R -- Fork --> F[(Forked<br/>Repository)]
  F <-. Push/Pull .-> C_4(<b>Clone</b><br/>Developer 4)

A fork allows you to essentially 'stand on the shoulders of giants'; i.e. you can use an existing codebase as a foundation, but adapt the project to go in an entirely different direction. For example, the MariaDB database application started as a fork from the well-known MySQL database application.