Hello everyone, when calling ReceiveChannel<T&g...

# coroutines

[zeugederunity]

Hello everyone,
when calling ReceiveChannel<T>::receiveCatching i get an object of type ChannelResult<ChannelResult<T>> back.
But when i call ReceiveChannel<T>::receive i get an object of type T.

Is this a bug or did i miss something in the API?

Thanks in advance!

[diesieben07]

receive will throw an exception if the channel is closed. receiveCatching doesn't throw, it returns you a failed ChannelResult instead.

[zeugederunity]

Yes, but as far as i understood the documentation of receiveCatching it should return a ChannelResult<T>, not a ChannelResult<ChannelResult<T>>

[diesieben07]

Oops, I completely skipped that part of your question... Yes it should not do that as far as I can tell

[efemoney]

Can you post the body of the particular function (plus context)? I used those apis and cannot see the same issue

[Justin]

If you make heavy use of smart casting and generics, you may have accidentally specified a generic type to be ChannelResult<T> instead of T .
Create a temporary variable val tempVariable = {yourChannelVariable} and set it to the channel in question, then have the IDE add the explicit type. It’s likely that your channel’s type is ChannelResult<T> and not T

[zeugederunity]

Yes, i just created a minimum example:
https://github.com/FelixEngl/ReceiveChannelStangeBehaviourME/tree/main

[zeugederunity]

After testing around i decided to make a bugreport. This behaviour just occurs with JVM, but on with JS.

[zeugederunity]

It is a compiler issue: https://github.com/Kotlin/kotlinx.coroutines/issues/2802