Version bump git tag in Go

bump-tag.go

package main

import (
	"fmt"
	"log"
	"os"

	"github.com/Symantec/Dominator/lib/verstr" // sorts semvers
	"github.com/libgit2/git2go"                // git access to read/write tags
	"github.com/olivoil/bump"                  // semantically bump tag number
)

/*
Tags the HEAD commit of the git repo in the current directory with a
semver string one patch version higher than the previous highest.
*/
func main() {

	// path is current directory
	pwd, err := os.Getwd()
	if err != nil {
		log.Fatal(err)
	}

	// find repo in path
	repo, err := git.OpenRepository(pwd)
	if err != nil {
		log.Fatal(err)
	}

	// get tags
	tags, err := repo.Tags.List()
	if err != nil {
		log.Fatal(err)
	}

	// sort tags and pick last (latest)
	verstr.Sort(tags)
	last := tags[len(tags)-1]

	// new string with bumped version number
	bumped, err := bump.String("patch", last)
	if err != nil {
		log.Fatal(err)
	}

	// get current HEAD ref
	head, err := repo.Head()
	if err != nil {
		log.Fatal(err)
	}

	// commit to tag is at current HEAD
	headCommit, err := repo.LookupCommit(head.Target())
	if err != nil {
		log.Fatal(err)
	}

	// tag creation requires a tag name string and a commit
	newtag, err := repo.Tags.CreateLightweight(bumped, headCommit, false)
	if err != nil {
		log.Fatal(err)
	}

	// done
	fmt.Printf("bumped %s to %s on %s\n", last, bumped, newtag)

}