Do not allow force push to master

At BigBinary we create a branch for every issue. We deploy that branch and only when it is approved that branch is merged into master.

Time to time we rebase the branch. And after rebasing we need to do force push to send the changes to github. And once in a while someone force pushes into master by mistake. We recommend to set push.default to current to avoid such issues but still sometimes force push does happen in master.

In order to prevent such mistakes in future we are using pre-push hook. This is a small ruby program which runs before any git push command. If you are force pushing to master then it will reject the push like this.

*************************************************************************
Your attempt to FORCE PUSH to MASTER has been rejected.
If you still want to FORCE PUSH then you need to ignore the pre_push git hook by executing following command.
git push master --force --no-verify
*************************************************************************

Requirements

pre-push hook was added to git in version 1.8.2. So you need git 1.8.2 or higher. You can easily upgrade git by executing brew upgrade git .

$ git --version
git version 1.8.2.3

Setting up hooks

In order for these hooks to kick in they need to be setup.

First step is to clone the repo to your local machine. Now open ~/.gitconfig and add following line.

[init]
  templatedir= /Users/neeraj/code/tiny_scripts/git-hooks

Change the value /Users/neeraj/code/tiny_scripts/git-hooks to match with the directory of your machine.

Making existing repositories aware of this hook

Now pre-push hook is setup. Any new repository that you clone will have the feature of not being able to force push to master.

But existing repositories do not know about this git-hook. To make existing repositories aware of this hook execute following command on all repositories.

$ git init
Reinitialized existing Git repository in /Users/nsingh/dev/projects/streetcommerce/.git/

Now if you look into the .git/hooks directory of your project you should see a file called pre-push.

$ ls .git/hooks/pre-push
.git/hooks/pre-push

It means this project is all set with pre-push hook.

New repositories

When you clone a repository then git init is invoked automatically and you will get pre-push already copied for you. So you are all set for all future repositories too.

How to ignore pre-push hook

To ignore pre-push hook all you need to do is

# Use following command to ignore pre-push check and to force update master.
git push master --force --no-verify

The hook is here .