main.go

package main

import (
	"flag"
	"log"
	"sync"
	"time"

	"github.com/go-git/go-git/v5"
	"github.com/go-git/go-git/v5/plumbing/object"
)

type Commit struct {
	hash         string
	author       string
	date         time.Time
	total        int
	runningTotal int
}

func main() {
	repoPath := "."
	flag.Parse()

	if flag.Arg(0) != "" {
		repoPath = flag.Arg(0)
	}

	r, err := git.PlainOpen(repoPath)
	if err != nil {
		log.Fatal(err)
	}

	ref, err := r.Head()
	if err != nil {
		log.Fatal(err)
	}

	// ... retrieves the commit history
	cIter, err := r.Log(&git.LogOptions{From: ref.Hash()})
	if err != nil {
		log.Fatal(err)
	}

	// git rev-list HEAD --count
	count := 0
	err = cIter.ForEach(func(c *object.Commit) error {
		count++
		return nil
	})
	if err != nil {
		log.Fatal(err)
	}

	log.Printf("Total commits: %d", count)

	cIter, err = r.Log(&git.LogOptions{From: ref.Hash()})
	if err != nil {
		log.Fatal(err)
	}

	commits := make([]Commit, count)

	log.Printf("Commits: %d", len(commits))

	// LOOK HERE
	// WORKS WITH 1 WORKER, FAILS WITH 2 OR MORE
	semaphore := make(chan bool, 1)
	wg := sync.WaitGroup{}
	countIndex := 0

	err = cIter.ForEach(func(c *object.Commit) error {
		wg.Add(1)
		semaphore <- true
		go func(c *object.Commit, countIndex int) {
			defer func() {
				<-semaphore
				wg.Done()
			}()

			fStats, err := c.Stats()
			total := 0
			if err != nil {
				log.Fatal(err)
			}
			for _, fStat := range fStats {
				// log.Println(fStat.Name, fStat.Addition, fStat.Deletion)
				total += fStat.Addition - fStat.Deletion
			}
			commits[countIndex] = Commit{
				hash:   c.Hash.String()[:7],
				author: c.Author.Name,
				total:  total,
				date:   c.Author.When,
			}
		}(c, countIndex)
		countIndex++
		return nil
	})

	if err != nil {
		log.Fatal(err)
	}

}