why does `Publisher<T>.asFlow()` not support...

# coroutines

[christophsturm]

why does Publisher<T>.asFlow() not support nullable values? https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-reactive/kotlinx.coroutines.reactive/org.reactivestreams.-publisher/as-flow.html

[elizarov]

Reactive streams specification explitcly prohibits nulls (See subscriber rule #13): https://github.com/reactive-streams/reactive-streams-jvm

[christophsturm]

i was confused because i use r2dbc with coroutines, with code like this:

val selectResult: Result =
                connection.createStatement("select * from users").execute().awaitSingle()
            val namesFlow =
                selectResult.map { row, _ -> row.get("NAME", String::class.java) as String }.asFlow()

and it always worked but with IDEA EAP i needed to add the “as string” cast. (row.get is a java method annotated as nullable)