如何在不使用接收到的数据的情况下释放go通道？

I created a channel and want to discharge it without using received values. However, compiler doesn't allow me to write code like this:

for i := range ch {
// code
}

complains that i is unused

substituting _ for i doesn't work either

What is the idiomatic way to do it?

Try this:

package main

import (
    "fmt"
)

func main() {
    ch := make(chan int)
    close(ch)
    for range ch {
        fmt.Println("for")
    }
    fmt.Println("done")
}

output:

done

You could use select instead of range:

for {
        select {
        // read and discard
        case <-ch:
        // to avoid deadlock
        default:
            continue
        }

    }

But then again, are you sure you really need the channel if you're not reading from it?

If you don't want to stuck in infinite loop read values until channel is not empty:

exitLoop:
for {
    select {
    case <-ch:
    default:
        break exitLoop
    }
}

Demo: https://play.golang.org/p/UsIqdoAGZi

If you need "updatable channel" - which keeps only 1 last value, you may use this recipe - https://stackoverflow.com/a/47107654/5165332