System.Concurrency.channelGet is hard to use and too coupled into scheme support code

[jarlah]

I hope its appropriate that i create an issue for this.

I am trying to get idris2-http "up and running" in the sense that i can use it in a real world scenario. Currently it only supports normal transfer encoding. It doesnt support chunked transfer encoding, due to how channels are implemented in base lib.

i have an issue with reproducible code here idris-community/idris2-http#15. Its a bit high level, but i dont think its very hard to spot where the problem is: in the scheme support code. Its not implemented to work the way i want it to work.

Steps to Reproduce

Run the example in the linked PR. its a standard pack project. I use repl. Should be no different since i use :exec. I like to inspect types.

Expected Behavior

I dont get stuck waiting for more data when there is more data to fetch.

Observed Behavior

It gets stuck when waiting for more data, when calling channelGet channel. But i honestly think it needs to be redesigned if it should work differently.

[gallais]

Looks to me like you could maybe have a variant of blodwen-channel-get that does not use
channel-get-while-helper and returns Nothing if either the mutex could not be acquired or
the box was empty.

[Matthew-Mosior]

I'm taking a look into this.