TyrianZIOApp hides thrown exceptions

[zynque]

I have noticed that when using TyrianZIOApp and my update function throws an exception, the app freezes but no exception is visible in the console. TyrianIOApp, on the other hand, displays the exceptions just fine. Here are a couple of Github Gists that demonstrate.

ZIO: https://gist.github.com/zynque/4de5e5ccd8569b1d8d4306011a955efa

Cats IO: https://gist.github.com/zynque/9ba27c9dec5960b1c0ab5e0541c4ebec

Here are the library versions I'm currently using:

  ThisBuild / scalaVersion      := "3.6.2" 
  libraryDependencies ++= Seq(
    "io.indigoengine" %%% "tyrian-zio"       % "0.12.0",
    "io.indigoengine" %%% "tyrian-io"        % "0.12.0",
    "dev.zio"         %%% "zio-interop-cats" % "23.1.0.3"
  )

[davesmith00000]

Thank you very much for the minimal examples, they were very helpful @zynque!

I have looked into this, but I haven't had time to minimise the issue and I'm not sure there's much I can do about it. At first I thought it might just be something about how I am using the update function, but no amount of reworking the runtime changed the behaviour at all.

Best guess is that it's a zio-interop-cats issue. In the Tyrian runtime (running ZIO) you can absolutely see the error and inspect it, but the main loop is run using background.surround via foreverM, and my hunch is that something in the interop layer isn't properly propagating the exceptions.

The unfortunate workaround of course is to use cats effect. In truth, I once saw (possibly on twitter, many moons ago) JDG say "If you didn't build it as a ZIO first lib and are just using interop, then it isn't really a ZIO app", and I regretfully have to agree with him. I'd love to say ZIO is a first class citizen, but it isn't and cannot be for purely technical / time / maintenance reasons. I'd have to make two separate core runtime libs specialised to each effect system, and I don't have the capacity to do that. Would be happy to accept a contribution though! 😄