Prevent commits in master branch

(For simplicity) I have a master branch and a dev in my Git repository. I want to ensure the master branch is always working, so all work I do should be in the dev branch.

However, when I merge my changes in with a --no-ff merge, I tend to stay in the master branch, and just continue working in it (because I forget to checkout my dev branch).

Can I put up a rule for the master branch, which states I can't do commits, and fast-forward merges, but only --no-ff merges from another branch?

This must work for private hosted repositories (ergo, not GitHub or Bitbucket).

Solution

Yes, it is possible. You must create a pre-commit hook which rejects commits to the master branch. Git doesn't call a pre-commit hook when you call the merge command, so this hook will be rejecting only regular commits.

Go to your repository.

Create a file, .git/hooks/pre-commit, with the following content:

#!/bin/bash

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

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

Make it executable (not required on Windows):
```
chmod +x .git/hooks/pre-commit
```

To disable fast-forward merges, you must also add the following option to your .git/config file:

[branch "master"]
    mergeoptions = --no-ff

If you want also protect the master branch on your remote, check this answer: How to restrict access to master branch in Git