Is it possible panic here?-CodePudding

func main() {
    rand.Seed(time.Now().Unix())
    ctx, cancelFunc := context.WithCancel(context.Background())
    anies := make(chan any)
    go doSomething(ctx, anies)
    intn := rand.Intn(2)
    if intn == 0 { //BRANCH1
        cancelFunc()
        close(anies) 
    }
    time.Sleep(time.Second)
}

func doSomething(ctx context.Context, anies chan any) {
    for {
         if ctx.Err() == nil { //LINE2
            anies <- 1 //LINE3
        }
    }
}

Can it be possible that somewhen BRANCH1 happens between LINE2 AND LINE3 and I will got panic.

CodePudding user response：

Yes, a panic is possible. Here's an example timeline where a panic occurs. The lines are in increasing time order. The N: prefix represents the goroutine.

1: start goroutine 2
2: call ctx.Err(), it returns nil
1: call cancelFunc()
1: close channel anies
2: send to channel anies. panic because channel is closed.