Demonstrate corrupted concurrent Go tar writing

concurrenttar.go

package main

import (
	"archive/tar"
	"bytes"
	"fmt"
	"io"
	"log"
	"os"
	"sync"
)

func main() {
	// Create and add some files to the archive.
	var buf bytes.Buffer
	tw := tar.NewWriter(&buf)
	var files = []struct {
		Name, Body string
	}{
		{"readme.txt", "This archive contains some text files."},
		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
		{"todo.txt", "Get animal handling license."},
	}
	var wg sync.WaitGroup
	for _, file := range files {
		wg.Add(1)
		go func() {
			defer wg.Done()
			hdr := &tar.Header{
				Name: file.Name,
				Mode: 0600,
				Size: int64(len(file.Body)),
			}
			if err := tw.WriteHeader(hdr); err != nil {
				log.Fatal(err)
			}
			if _, err := tw.Write([]byte(file.Body)); err != nil {
				log.Fatal(err)
			}
		}()
	}
	wg.Wait()
	if err := tw.Close(); err != nil {
		log.Fatal(err)
	}

	// Open and iterate through the files in the archive.
	tr := tar.NewReader(&buf)
	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			break // End of archive
		}
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("Contents of %s:\n", hdr.Name)
		if _, err := io.Copy(os.Stdout, tr); err != nil {
			log.Fatal(err)
		}
		fmt.Println()
	}

}