Are channels closed by garbage collector?

[amano-kenji]

I don't know whether garbage collector closes channels.

[CosmicToast]

When a channel gets garbage-collected, it calls the deinit function.
Closing a channel calls cfun_channel_close.

These aren't exactly the same,
closing the channel makes all queued and future reads and writes return nil,
while deinitializing deinitializes (a simple free) both of those queues.

Whether this makes any difference is a question for your code.
Test it out!

If you want to make it such that the answer is an unambiguous "yes", just add a constructed call of cfun_channel_close to the gc function before deinitializing.

[amano-kenji]

I think garbage collection doesn't kick in for a channel as long as the channel is used.

Garbage collection kicks in only after the channel stops being referenced anywhere.

[amano-kenji]

I think the current codebase does the right thing.