Git commit-msg hook to append issue number to commit message

commit-msg

#!/bin/bash

# This hook both checks that the name of the branch matches a given convention 
# and extracts the issue number from the branch name to add it to the commit message.
# If it is a multiline commit message the reference to the issue is added as a new line.
# In the case of a single line commit message, the reference is added at the end of the message.

BRANCH_NAME_REGEX="^(ci|docs|feature|fix|hotfix|perf|refactor|test)\/.*$"
ISSUE_NUMBER_REGEX="^.*\#([0-9]+)"

BRANCH_NAME=$(git rev-parse --abbrev-ref HEAD)

echo $BRANCH_NAME

if ! [[ $BRANCH_NAME =~ $BRANCH_NAME_REGEX ]]; then
    echo "*** Commit interupted ***"
    echo "Your branch name does not match the naming convention."
    echo "Branch names should follow \"$BRANCH_NAME_REGEX\"..."

    exit 1
fi

if [[ $BRANCH_NAME =~ $ISSUE_NUMBER_REGEX ]]; then

    ISSUE_NUMBER="#${BASH_REMATCH[1]}"

    FILE=$1

    if ! grep -q $ISSUE_NUMBER $FILE; then

        if [[ $(wc -l < $FILE) -gt 1 ]]; then
            # Multiline message, we add at the end of the file
            echo "Refs $ISSUE_NUMBER" >> $FILE
        else
            # Single line message, we add at the end of the message
            echo $(sed -e "s/$/ (refs $ISSUE_NUMBER)/" $FILE) > $FILE
        fi
        echo "Reference to issue \"$ISSUE_NUMBER\" was added to your commit message..."
    fi
fi