Proposal: New Effects4s about cats-effect HOT 2 CLOSED

Relaxing the laws of the effects4s Async (or at least, relaxing the stack-safety constraint) does indeed make this possible, so it just comes down to exactly what we want here.

I have a couple concerns:

• This would add another dependency to cats-effect, and indeed everything downstream, which is a bit of a significant load to take on. The bar for stability on effects4s would indeed be extremely high, and given the comparatively large number of typeclasses in the library, I'm concerned on that front.
  • We could potentially mitigate this using "provided", basically opening the door for downstream projects to ignore effect4s if they so choose, or if they need the conversions, bring in the dependency explicitly.
• If the point of effects4s is interop, why do we need more than just Async?
  • As a sidebar, I find it pretty unlikely that you'll be able to define a useful set of laws which simultaneously characterize lazy effect types (like Task or IO) and eager, memoizing containers like Future, but I admit that would be quite cool
• I'm not particularly fond of unsafeExtractTrySync, since it forces you to provide two handlers. Effectively, it's like the inconvenience of both the synchronous and the asynchronous extractors, all in one.

from cats-effect.

I've thought more about it today - currently not very enthusiastic about this. Closing this issue for now and I'm postponing further development, because I'm behind on Monix, cats-effect is currently more exciting, etc.

We could potentially mitigate this using "provided"

Does this work? It would be awesome if it did, but I tried doing this with cats-core by means of macros (to avoid bytecode signatures that would trigger ClassNotFoundException), but whenever a compiler error happens, it starts triggering really nasty exceptions -- so when the compiler doesn't find some method you want to call on a type, it probably starts looking for implicit conversions, which triggers those macros, which then trigger classpath errors.

from cats-effect.