Hello,

@Test
    fun example() = runBlocking {
        val a = produce {
            var i = 0
            while (isActive) {
                send(i++)
                delay(100)
            }
        }
        val b = a.broadcast(start = CoroutineStart.DEFAULT)

        launch {
            b.consumeEach {
                println("A: $it")
            }
        }
        
        b.close()

        delay(1_000)
    }

When I close b broadcast channel I get an exception:

Exception in thread "Test worker @coroutine#3" kotlinx.coroutines.channels.ClosedSendChannelException: Channel was closed (Coroutine boundary)

Is this the expected behavior?

Yes. The coroutine was unconditionally waiting for the channel and the only way to interrupt it is with an exception.

exception is thrown at send()

val a = produce { while (isActive) send(1) }
        val b = a.broadcast(start = CoroutineStart.DEFAULT)
        b.close()

also throws an exception

Does,

val a = produce { while (isActive) send(1) }
a.close()

throw an exception? (Not on computer to check)

produce return a ReceiveChannel. ReceiveChannel does not have a close operation. If I call a.cancel() it works. But what I really want to understand if this is a bug in coroutines because it seems like one.