Bump a git repo semver tag.

bump-version-tag.sh

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

__THIS_FILE__="$(basename "${BASH_SOURCE[0]}")"

SEMVER_REGEX="^[vV]?(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(\\-[0-9A-Za-z]+){0,1}$"
SEMVER_MAJOR=0
SEMVER_MINOR=0
SEMVER_PATCH=0
SEMVER_SUFFIX=""
NEW_SUFFIX=""
LIGHTWEIGHT_TAG=1
VERSION_BUMPED=0
NEW_VERSION=""
PUSH_TAGS_TO_REPO=""
PREVIOUS_HIGHEST_VERSION=""

function print-usage () {
    cat <<USAGE

Usage: bash ${__THIS_FILE__} [OPTIONS]

OPTIONS
  --release  Creates an annotated tag, instead of the default lightweight git tag.
             For more information regarding annotated and lightweight tags see https://git-scm.com/book/en/v2/Git-Basics-Tagging
  --major    Bumps the 'major' part of the version string. May be used multiple times.
  --minor    Bumps the 'minor' part of the version string. May be used multiple times.
  --patch    Bumps the 'patch' part of the version string. May be used multiple times.
             This is option is assumed by default if no other option is passed when the script runs.
  --suffix <alphanum value>  Sets the suffix of the version - e.g. rc1, beta
  --push-to <repository> Name of the remote repository to which the newly created tag will be pushed to. e.g. --push-to remote-source-of-truth

USAGE
}


function exit-error () {
    echo "$(date +'%Y-%m-%d %H:%M:%S') ERROR: ${1}" 1>&2;
    exit 127
}


function set-version-variable () {
    NEW_VERSION="v${SEMVER_MAJOR}.${SEMVER_MINOR}.${SEMVER_PATCH}${NEW_SUFFIX}"
}


function extract-version () {
    local VERSION=${1}
    if [[ "${VERSION}" =~ ${SEMVER_REGEX} ]]; then
        SEMVER_MAJOR=${BASH_REMATCH[1]}
        SEMVER_MINOR=${BASH_REMATCH[2]}
        SEMVER_PATCH=${BASH_REMATCH[3]}
        SEMVER_SUFFIX=${BASH_REMATCH[4]}
    else
        exit-error "Invalid semver string passed to 'extract-version'"
    fi
}


function bump-version () {
    case "${1}" in
        major)
            SEMVER_MAJOR=$((SEMVER_MAJOR + 1))
            SEMVER_MINOR="0"
            SEMVER_PATCH="0"
            ;;

        minor)
            SEMVER_MINOR=$((SEMVER_MINOR + 1))
            SEMVER_PATCH="0"
            ;;

        patch)
            SEMVER_PATCH=$((SEMVER_PATCH + 1))
            ;;

        suffix)
            if [[ "${2:-}" =~ ^[0-9A-Za-z]+$ ]]; then
                NEW_SUFFIX="-${2}"
            else
                exit-error "Invalid suffix string."
            fi
            ;;
        *)
            exit-error "Unknown option passed to 'bump-version'"
            ;;
    esac
    VERSION_BUMPED=1
}


function find-last-tag-in-current-repo () {
    PREVIOUS_HIGHEST_VERSION=$(git tag -l --sort=-version:refname "v*" | head -n1)

    if [[ "x" != "x${PREVIOUS_HIGHEST_VERSION}" ]]; then
        echo "This repo's current highest version is ${PREVIOUS_HIGHEST_VERSION}"
        echo "This branch's highest version is $(git describe --tags --always --first-parent)"
    fi
}

function add-new-tag-to-repo () {
    set-version-variable;
    if [[ $(git tag -l "${NEW_VERSION}") ]]; then
        exit-error "The tag ${NEW_VERSION} already exist."
    else
        if [[ 1 -eq ${LIGHTWEIGHT_TAG} ]]; then
            echo "Creating lightweight tag ${NEW_VERSION}"
            git tag "${NEW_VERSION}"
        else
            echo "Creating annotated tag ${NEW_VERSION}"
            git tag -a "${NEW_VERSION}" -m "Release version ${NEW_VERSION}"
        fi
    fi
}


#
# *** MAIN ***
#

if [[ $# -eq 0 ]]; then
    print-usage
    exit 0
fi

while [[ $# -gt 0 ]]; do
    find-last-tag-in-current-repo
    extract-version ${PREVIOUS_HIGHEST_VERSION}
    case ${1} in
        --major|--minor|--patch )
            bump-version ${1//-/}
            shift
            ;;

        --suffix )
            bump-version suffix ${2}
            shift
            shift
            ;;

        --release )
            LIGHTWEIGHT_TAG=0
            shift
            ;;

        --push-to )
            PUSH_TAGS_TO_REPO=${2}
            shift
            shift
            ;;

        -h|--help )
            print-usage
            exit 0
            ;;

        * )
            echo "Error: Unknown option \"${1}\""
            exit 127
    esac
done

if [[ 1 -eq ${VERSION_BUMPED} ]]; then
    [[ -f ./.VERSION ]] && rm -f ./.VERSION

    add-new-tag-to-repo

    if [[ "x" != "x${PUSH_TAGS_TO_REPO}" ]]; then
        echo "# git push --tags \"${PUSH_TAGS_TO_REPO}\" HEAD"
        git push --tags "${PUSH_TAGS_TO_REPO}" "refs/tags/${NEW_VERSION}"
    fi

    echo ${NEW_VERSION} > ./.VERSION
fi