A Git hook to prevent committing directly to main

At work, we use a standard Git workflow: develop on a feature branch, push to GitHub, and open a pull request to main. Once somebody else approves the PR, the changes get merged.

At least once a week, I forget to branch and commit changes directly to my local main.

I only realise my mistake when I try to push and GitHub blocks me. To untangle myself, I have to create a new branch with my current state, push that instead, and then reset my local main back to origin so I can pull other people’s changes. This isn’t difficult to fix, but it’s annoying – especially when I often forget to clean up my local main until the next time I try to pull.

To stop me getting into this state, I’ve written a Git pre-commit hook. I saved the following shell script in .git/hooks/pre-commit and made it executable:

#!/usr/bin/env bash

set -o errexit
set -o nounset

branch="$(git rev-parse --abbrev-ref HEAD)"

if [ "$branch" = "main" ]; then
   echo "You can't commit directly to main"
   exit 1
fi

The git rev-parse command prints the short name of the current HEAD. If I’m on a branch, it returns the branch name; if I’m in a detached HEAD state, it returns HEAD.

If the hook detects that I’m on main, it exits with an error code. This aborts the commit and prevents it being saved, serving as a friendly reminder to create a feature branch first – and leaving my local main completely clena.

Ideally I’d always remember to branch when I start a new piece of work – but since I don’t, I’m happy to let the computer remember instead.