Goroutine storage channel value has no deadlock

Question

This code runs and ends with no deadlock error. Why?

func main() {
    ch := make(chan int)
    go func() {
        ch<-1
        ch<-2
    }()

    time.Sleep(time.Second)
}

Answer 1

The unbuffered channel needs two end points to work, so let's start with correct example:

package main

func main() {
    go fun2()
    <-ch
    <-ch
}
func fun2() {
    ch <- 1
    ch <- 2
}

var ch = make(chan int)

Here fun2() sends two values and main() receives two values.

---

Your sample code has only one end point so the channel is not correctly constructed, so it is deadlock , but the main goroutines exits normally so you don't see the error. Here, there is no second end point, so this is deadlock:

package main

func main() {
    var ch = make(chan int)
    ch <- 1
}

Output:

fatal error: all goroutines are asleep - deadlock!