Single writer, multiple readers google/btree data race

google_btree_data_race_detect.go

package main

import (
	"math/rand"
	"sync"
	"time"

	"github.com/google/btree"
)

// perm returns a random permutation of n Int items in the range [0, n).
// credits for this fn: github.com/google/btree/btree_test.go
func perm(n int) (out []btree.Item) {
	for _, v := range rand.Perm(n) {
		out = append(out, btree.Int(v))
	}
	return
}

func btreeReader(tr *btree.BTree, quitCh chan struct{}, wg *sync.WaitGroup) {
	n := 10
	items := perm(n)
	for {
		select {
		case <-quitCh:
			wg.Done()
			return
		default:
			i := rand.Intn(n)
			tr.Get(items[i])
		}
	}
}

func btreeWriter(tr *btree.BTree, quitCh chan struct{}, wg *sync.WaitGroup) {
	n := 10
	items := perm(n)
	for {
		select {
		case <-quitCh:
			wg.Done()
			return
		default:
			i := rand.Intn(n)
			if i%2 == 0 {
				tr.ReplaceOrInsert(items[i])
			} else {
				tr.Delete(items[i])
			}
		}
	}
}

func main() {
	numReaders := 10
	quitCh := make(chan struct{}, numReaders+1)
	var wg sync.WaitGroup
	wg.Add(numReaders + 1)

	// btree
	tr := btree.New(20)

	// start readers
	for i := 0; i < numReaders; i++ {
		go btreeReader(tr, quitCh, &wg)
	}

	// start single writer
	go btreeWriter(tr, quitCh, &wg)

	time.Sleep(3 * time.Second)
	for i := 0; i < numReaders+1; i++ {
		quitCh <- struct{}{}
	}
	wg.Wait()
}