A program that recreates its own repository. Why? Because fun!
How do you mean? It's a quine. It produces itself as output. There is nothing to install.
Bäärenkatapulte!
Just run it! It should produce exactly the same commits on every platform.
$ ls -a
.git .gitignore git_quine.py LICENSE README.md
$ ./git_quine.py
Git repository created in git_quine/
$ ls git_quine/
.git .gitignore git_quine.py LICENSE README.md
$ diff -su <(git rev-parse HEAD) <(git -C git_quine/ rev-parse HEAD)
Files /dev/fd/63 and /dev/fd/62 are identical
To prove that it doesn't just copy the files, I encourage you to take git_quine.py,
move it somewhere else, delete the repository, and run the quine.
You will see that it reproduces the entire repository without access to anything else.
This quine supports arbitrary commit messages and times, added files, and changes to files.
Naturally, it can't reproduce all features of git. Most importantly, this quine currently only understands history as a single branch, consisting only of single-parent commits. Also, this quine is its own author and committer, because that simplifies things.
Diffs are stored inefficiently.
If you take a deep dive into how this quine works, you will see that these missing features can be easily added.
Feel free to dive in! Open an issue or submit PRs.