git checkout2

An opinionated wrapper around git checkout that helps you jump where you need to go.

The Pitch

Consider this: you're working with multiple worktrees, and you type git checkout dev. The expected next state is that your current directory is populated with files at dev, and your probably want to get straight to making edits on dev. However, if dev is already checked out in another worktree, then git checkout will fail. Wouldn't it be nice if we could just parse that message on stderr and jump straight to that worktree?

How to use git-checkout2

1. Install git-checkout2 with

   make configure
   make install
   

   (you can change the installation directory in CMakeLists.txt)

2. In your .bashrc or .zshrc, add simple function to wrap git-checkout2. This is because running any binary directly will never be able to change your current directory in the interactive shell. Here's a suggested (POSIX-compliant) function:

   gco() {
     TARGET=$(git checkout2 $1)
     EXIT_CODE=$?
     if [ $EXIT_CODE -eq 64 ]; then
       cd $TARGET
     fi
     unset TARGET
     return $EXIT_CODE
   }

The Promise

git-checkout2 does two very simple things. For this discussion, assume that we setup gco like the above, and we run the shell command gco GOAL.

1. If the GOAL branch is already used in another worktree, then we'll be transported there with the cd command.

2. If the first condition fails to find matches, and if somehow there is a worktree whose directory name is GOAL, then we'll be transported there instead.

   • This is useful when you have more branches than worktrees, and the worktrees are no longer pointing to their original respective branches.

3. It does all this with zero heap allocation.

The Boundaries

In the spirit of simplicity (this project is already an over-engineered shell script), git-checkout2 will only accept one shell argument. That is, if more than 1 argument (or no arguments) is supplied to git-checkout2, then it will simply forward all those arguments to git checkout. This eases the load of argument parsing.

Testing

Tests are written in Rust, since I do feel like that's the best language for ensuring correctness. These can be found in tests/.

Nerding out

This was originally nothing more than a long-winded zsh function living in my .zshrc. But at some point I wanted to change some behavior, and I found it very hard to read zsh code I've written a long time ago. So I rewrote it in Rust. But Rust's standard library API for Command and piping forced me to heap-allocate, which I just didn't want. And so since this project is small enough, I wrote it all in C and here we are. I'm pretty happy about it, despite its simplicity. Thanks for reading, and happy hacking!