servant-auth-client test failure on macOS

[domenkozar]

https://nix-cache.s3.amazonaws.com/log/7liljvzs9fbj1844y4iw0agnqlbmwfcd-servant-auth-client-0.3.3.0.drv

Failures:

  test/Servant/Auth/ClientSpec.hs:68:3: 
  1) Servant.Auth.Client, The JWT combinator, HasClient, fails when token is expired
       uncaught exception: IOException of type ResourceExhausted
       /dev/urandom: openFd: resource exhausted (Too many open files)
       (after 47 tests)

  To rerun use: --match "/Servant.Auth.Client/The JWT combinator/HasClient/fails when token is expired/"

Randomized with seed 1188103930

Seems like entropy source is not closed correctly.

[domenkozar]

https://github.com/haskell-crypto/cryptonite/blob/4622e5fc8ece82f4cf31358e31cd02cf020e558e/Crypto/Random/Entropy/Unix.hs#L48 is called as part of entropyOpen so the exhaustion happened somewhere else.

[erewok]

I was experimenting with something in this library and while trying to run the tests, I hit this same bug on OSX 10.15.5 (Catalina). After hunting around for awhile, I followed the same path, signing JWTs invokes cryptonite which opens /dev/urandom... (I landed here because it's the only googleable result that matches.)

Ultimately, I got around this by running ulimit -n 2048 in the same shell where I was running tests because OSX has a file descriptor limit of 256 for shell processes, but I'm still puzzled. If anyone comes here from the future, that's what I did... 🤷‍♀️