create too many commits

complete.go

package main

import (
	"fmt"
	"os"
	"time"

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

// Builder build compile
type Builder struct {
	repo      *git.Repository
	tree      plumbing.Hash
	parent    plumbing.Hash
	message   string
	author    object.Signature
	committer object.Signature
	refName   plumbing.ReferenceName
}

// NewBuilder new builder
func NewBuilder(dir string) (*Builder, error) {
	repo, err := git.PlainOpen(dir)
	if err != nil {
		return nil, err
	}
	ref, err := repo.Head()
	if err != nil {
		return nil, err
	}
	commit, err := repo.CommitObject(ref.Hash())
	if err != nil {
		return nil, err
	}
	return &Builder{
		repo:      repo,
		parent:    ref.Hash(),
		message:   commit.Message,
		author:    commit.Author,
		committer: commit.Committer,
		tree:      commit.TreeHash,
		refName:   plumbing.NewBranchReferenceName("master")}, nil
}

// Build todo
func (b *Builder) Build() error {
	now := time.Now()
	var total int64
	for now.Year() < 2101 {
		total++
		b.author.When = now
		b.committer.When = now
		newCommit := &object.Commit{
			Author:       b.author,
			Committer:    b.committer,
			TreeHash:     b.tree,
			Message:      b.message,
			ParentHashes: []plumbing.Hash{b.parent},
		}
		obj := b.repo.Storer.NewEncodedObject()
		if err := newCommit.Encode(obj); err != nil {
			return err
		}
		oh, err := b.repo.Storer.SetEncodedObject(obj)
		if err != nil {
			return err
		}
		b.parent = oh
		ref := plumbing.NewHashReference(b.refName, oh)
		if err := b.repo.Storer.SetReference(ref); err != nil {
			return err
		}
		fmt.Fprintf(os.Stderr, "\x1b[2K\r\x1b[01;32m%s total: %d\x1b[0m", oh.String(), total)
		now = now.Add(time.Hour * 8)
	}
	return nil
}

func main() {
	if len(os.Args) < 2 {
		fmt.Fprintf(os.Stderr, "usage: %s git-dir\n", os.Args[0])
		os.Exit(1)
	}
	b, err := NewBuilder(os.Args[1])
	if err != nil {
		fmt.Fprintf(os.Stderr, "unable open repo: %v\n", err)
		os.Exit(1)
	}
	if err := b.Build(); err != nil {
		fmt.Fprintf(os.Stderr, "unable create commit: %v\n", err)
		os.Exit(1)
	}
}