Are you using arch by any chance?
It looks like the libs are built out of order leading to this issue.

Yes, I am, but this doesn't just affect the AUR package. I got this same error when I cloned from Github and followed the instructions.

I've provided what additional info I thought necessary to move this along. Is there more I can provide so that this could be resolved, @gallais ?

Ah, I hadn't noticed you were the one who had posted the upstream issue. 😅
I know next to nothing about the network code so it's probably better if
someone more knowledgeable steps in.

I can confirm this issue is still present on 0.3.0.

I don't know much about the network code, but the error is raised when the test code tries to bind a new socket on localhost:0 (which should mean a free port on localhost). Can you check if it is indeed possible to do so in your system?

@ShinKage Not a network expert - how would I check this?

@kozross Sorry, I must have involuntarily skipped the notification. I'm very far from a network expert myself but you can try to directly call the C primitives, simplifying all the checks done in the support library, in particular you can take a look at the two functions called by the test here and here. They will probably fail again, but maybe you can get more helpful error descriptions since the Idris2 support code does not propagate the exact error number.

99 is EADDRNOTAVAIL. What port is the server trying to start on in the test code?

Looks like 0

Binding to port 0 is not allowed, I'm pretty sure.

From what I gather 0 means "just give me any port you like".

Either way, this is extremely flaky.