errors: race condition is detected when using errors.As() #67928
Description
Go version
go version go1.22.4 darwin/arm64
Output of go env in your module/workspace:
GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='/Users/yunbj/Library/Caches/go-build'
GOENV='/Users/yunbj/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/yunbj/Workspace/go/pkg/mod'
GONOPROXY='github.daumkakao.com'
GONOSUMDB='github.daumkakao.com'
GOOS='darwin'
GOPATH='/Users/yunbj/Workspace/go'
GOPRIVATE='github.daumkakao.com'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/Users/yunbj/Applications/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/Users/yunbj/Applications/go/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.22.4'
GCCGO='gccgo'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/Users/yunbj/Workspace/go/src/toy/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/sl/59_3w_5d2fnc85xsx_jr41zm0000gp/T/go-build3034457358=/tmp/go-build -gno-record-gcc-switches -fno-common'What did you do?
When I call errors.As in multiple goroutine, race detector reports race condition.
What did you see happen?
sample code is below:
package main
import (
"context"
"errors"
"fmt"
"sync"
"time"
)
var raceError = errors.New("race condition")
func isRaceError(err error) bool {
return errors.As(err, &raceError)
}
func somthingWrong() error {
return raceError
}
func checkRaceError() {
err := somthingWrong()
if isRaceError(err) {
fmt.Println("this is race error")
} else {
fmt.Println("this is not race error")
}
}
func worker(confirmStart, complete *sync.WaitGroup, wake <-chan struct{}, ctx context.Context) {
confirmStart.Done()
for {
select {
case <-ctx.Done():
complete.Done()
return
case <-wake:
checkRaceError()
}
}
}
func main() {
wg := sync.WaitGroup{}
confirmStart := sync.WaitGroup{}
ctx, cancel := context.WithCancel(context.Background())
const workers = 2
const repeat = 1
var wakeChannel = make([]chan struct{}, workers)
wg.Add(workers)
confirmStart.Add(workers)
for i := 0; i < workers; i++ {
wakeChannel[i] = make(chan struct{}, 1)
go worker(&confirmStart, &wg, wakeChannel[i], ctx)
}
confirmStart.Wait()
for i := 0; i < repeat; i++ {
fmt.Println("send signal")
for i := 0; i < workers; i++ {
wakeChannel[i] <- struct{}{}
}
time.Sleep(1 * time.Second)
}
cancel()
wg.Wait()
}When I run with -race, "race condition" report is shown.
$ go run -race main.go
send signal
this is race error
==================
WARNING: DATA RACE
Read at 0x000100e9c280 by goroutine 7:
main.checkRaceError()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:22 +0x28
main.worker()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:39 +0x40
main.main.gowrap1()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:59 +0x64
Previous write at 0x000100e9c280 by goroutine 6:
reflect.maplen()
/Users/yunbj/Applications/go/src/runtime/map.go:1406 +0x7c
internal/reflectlite.typedmemmove()
/Users/yunbj/Applications/go/src/runtime/mbarrier.go:221 +0x18
errors.as()
/Users/yunbj/Applications/go/src/errors/wrap.go:119 +0x1ec
errors.As()
/Users/yunbj/Applications/go/src/errors/wrap.go:113 +0x1d8
main.isRaceError()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:14 +0x4c
main.checkRaceError()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:23 +0x50
main.worker()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:39 +0x40
main.main.gowrap1()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:59 +0x64
Goroutine 7 (running) created at:
main.main()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:59 +0xb4
Goroutine 6 (running) created at:
main.main()
/Users/yunbj/Workspace/go/src/toy/errors.as/main.go:59 +0xb4
==================
this is race error
Found 1 data race(s)
exit status 66
What did you expect to see?
When I use "errors.Is()", no race condition is reported.
Even though error is wrapped, I expect that race condition is not occurred.