git: add ticket id from branch name as template commit message. Original from atlassian's https://github.com/atlassian/atlascode/blob/9cd9ae156dd7666c3b71b027afe7513a17c16b12/scripts/prepare-commit-jira.sh

prepare-commit-msg

#!/bin/sh
#
# Original from: https://github.com/atlassian/atlascode/blob/9cd9ae156dd7666c3b71b027afe7513a17c16b12/scripts/prepare-commit-jira.sh
#
# git prepare-commit-msg hook for automatically prepending an issue key
# from the start of the current branch name to commit messages.


# This commit hook will extract a Jira issue key from your branch name (you are naming your branches with issue key’s aren’t you?) and append it to all commit messages so that many places across our products can glue commits together with issues.
#
# To use this:
#
# Already cloned repositories: 
# 
# copy the file into the .git/hooks directory of the cloned directory, or run git init after configuring the templates (see bellow)
#
#
# To automatically add to hooks on git clone:
#
# make sure the folder(s) ~/.git-templates/hooks exists
# drop this file in there and make sure it’s named prepare-commit-msg
# make ~/.git-templates/hooks/prepare-commit-msg executable. (chmod +x)
# make sure your ~/.gitconfig contains
# [init]
# templatedir = ~/.git-template
# Now anytime you checkout a repo OR use git init in a directory, the prepare-commit-msg will be copied into your project’s .git/hooks folder.
#
# Note: You can safely run git init within pre-existing git projects to get the file copied over
#
# and… if the script isn’t running, double check your settings for core.hooksPath interfering:
# git config --show-origin core.hooksPath
#
# many thanks to contributions from 
# @foo @Erwin Vrolijk @Joshua Jacobson @Brett Taylor @Jonathan Doklovic

# check if commit is merge commit or a commit ammend
if [ "$2" = "merge" ] || [ "$2" = "commit" ]; then
    exit
fi
ISSUE_KEY=`git branch | grep -o "\* \(.*/\)*[A-Z]\{2,\}-[0-9]\+" | grep -o "[A-Z]\{2,\}-[0-9]\+"`
if [ $? -ne 0 ]; then
    # no issue key in branch, use the default message
    exit
fi

# check if a fixup commit, if it is, use default message
FIXUP_COMMIT=`grep -o "fixup\!" "$1"`
if [ $? -eq 0 ]; then
    exit
fi


# issue key matched from branch prefix, prepend to commit message
sed -i -e "1s/^/$ISSUE_KEY /" "$1"