After updating coroutines (android) from 1.2.1 to 1.3.0 (same if 1.3.1) I’m getting this crash:

"kotlinx.coroutines.channels.ClosedSendChannelException: Channel was closed"

when calling

SendChannel.send

(note: I’m using

produce

to build the channel). I’ve isolated the cause to be this upgrade. I couldn’t find anything relevant in the release notes: https://github.com/Kotlin/kotlinx.coroutines/releases . Any tips on how to investigate what could be causing this, please?

what does your

produce

look like?

Use

cancel()

instead of

close()

.

@louiscad I’m currently using

close()

because I have a reference to the channel (and I think there is no

cancel()

on

Channel

). Does this mean instead I need to hold onto a reference of the

Job

corresponding to the

Channel

instead (in order to cancel)?

there is a

cancel

on Channel

@octylFractal ah yes, sorry I was looking at

SendChannel

@Mark I think your best source is the documentation of both these functions. I learned about the difference between them the hard way after half an afternoon of debugging. You can submit an issue on GitHub to ask for it to be warned about in the guide/doc, and in the

close

function KDoc.

yes, this is not really a behavior change --

close

is for the sending side, indicating it is done sending,

cancel

is for the receiving side.

Thanks @octylFractal that makes sense not to call

close()

from the receiver. I was actually calling it from a class managing the channels (when the channel becomes obsolete due to external conditions). So now I know

cancel()

is the correct way 🙏 But yes, a thorough reading of the docs is probably a wise investment of time!

@Mark there's a major difference between cancel and close. Cancel causes elements not yet received to be dropped. Close doesn't.

@Dico if I want to discard a channel (from the receiver side) surely I want the not-yet-received elements to be dropped?

It’s https://github.com/Kotlin/kotlinx.coroutines/issues/957 since 1.3.0-M1.