Useful Git Hooks

Useful Git Hooks.md

#Useful Git Hooks

Below are a couple of simple git hooks that can be useful for controlling and formatting commits. These are generally re-hashes of other people's ideas, so I've credited these as appropriate.

Git Hooks

A git hook is a script that lives in your .git/hooks directory. The scripts are invoked when certain events occur within your repo, such as make a commit or pushing changes. Hooks can be used to automate and augment basic actions within your repos.

##Include an issue number in your commit message To amend your commit messages after they have been submitted, you'll need a commit-msg hook. I borrowed most of these ideas from @monkseal. This hook assumes that your issue numbers are formatted into you branch names in a way that you can extract using a regex.

To create a hook, just create a file with the name of the hook (e.g. commit-msg) and put it in your hooks directory. The file does not need to have an extension.

#!/bin/sh

getIssueRef() {
  # Amend the regex here to extract your issue reference from you're branch name.
  git rev-parse --abbrev-ref HEAD | grep -e '[A-Z]\+-[0-9]\+' -o
}

MESSAGE="$(cat $1)"
TICKET=`getIssueRef`

if [ -n "$TICKET" ]
then
   echo "New commit message: $TICKET : $MESSAGE"
   # This line outputs the re-formatted commit message with the issue number in.
   echo "$TICKET : $MESSAGE" > $1
fi

An alternative to re-formatting the commit messafge by prefixing it with the issue reference, might be to suffix it on a new line:

printf "$MESSAGE\n$TICKET" > $1

##Prevent commits from inadvertantly being made on master If you want to prevent accidental commits to a local master branch, you can use a pre-commit hook.

#!/bin/sh

currentBranch=`git rev-parse --abbrev-ref HEAD`
protectedBranch='master'

if [ $currentBranch = $protectedBranch ]
then
	echo "Please do not commit directly to master. Create  a topic branch and merge the change in GitHub"
	exit 1
fi