Channelterator hasNext()

[K0zka]

Hi kotlinx.coroutines team,

If you keep calling hasNext() on the channel iterator, it is moving the cursor. So for example
https://pl.kotl.in/5U-Z6RQd1

import kotlinx.coroutines.*
import kotlinx.coroutines.channels.Channel


fun main() : Unit = runBlocking {
    val channel = Channel<Int>()
    // producer
    launch {
        channel.send(1)
        channel.send(2)
        channel.close()
    }
    // consumer
    launch {
        val iterator = channel.iterator()
        repeat(10) {
            // only calling hasNext(), nothing else
            println(iterator.hasNext())
        }
    }
}

this will generate output

true
true
false
false
...

Strictly speaking, this is not the behavior one would expect from a function called hasNext() it should be only a query and should not have a side-effect. What do you think?

[lukellmann]

I think this will be fixed by #4065