Using retryEither with suspend functions?

[milgner]

Current version: arrow-resilience 1.2.4

Trying to convert some code that loads data over the network to retry in case of failure using arrow-resilience.
The existing code is a suspend function that returns an Either with the result or an error.

Now I noticed that retryEither is declared as

public suspend inline fun <Error, Result, Output> Schedule<Error, Output>.retryEither(
  @BuilderInference action: () -> Either<Error, Result>,
): Either<Error, Result>

But since my existing function is a suspend function, I can't use it for the action argument.

So I'm looking for a way to combine this. Ideally it would work the same with a signature like

public suspend inline fun <Error, Result, Output> Schedule<Error, Output>.retryEither(
  @BuilderInference action: suspend () -> Either<Error, Result>,
): Either<Error, Result>

[nomisRev]

Hey @milgner,

I think this is some kind-of mistake in the API. action should support through inline and suspend keyword on the main function, but apparently not the case so we need to explicitly specify suspend.

I think this can be considered a bug, and if you're interested I'd be great to have a ticket, or a PR for this!

[milgner]

Oh, alright! Thank you for the quick response! Since some of the other callbacks were already marked as suspend, I assumed that it was intentionally left out for retryEither. I'll gladly open a PR to change it 👍

[nomisRev]

Awesome, a PR would be wonderful! Thank you ☺️

[milgner]

Forgot about this as for some reason it started working again.

[kyay10]

I think the reason this started working again is maybe you were trying to use a reference instead of a lambda? retryEither(::someSuspendFunction) would not work, annoyingly. However, retryEither { someSuspendFunction() } absolutely works as long as you're already in a suspend context.