Given MonadError[F, Z], EitherT[F, E, ?] should provide a MonadError[..., Either[Z, E]]
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- Dominant language
- Scala
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Description
The title says it all, basically.
It's a known fact that something like EitherT[IO, E, ?] has two channels of failing: by raising the Throwable in IO and by raising a E in an inner Either. Instead of prioritizing the former, I suggest we expose the ability to work with both channels of failure directly by using a coproduct type.
Same applies to OptionT[F, A]
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
The issue names no files or tests. Start by locating the EitherT and OptionT definitions and their existing MonadError instances, then trace how the outer F failure and inner Either or Option failure are represented. Done means exposing both failure channels through the proposed coproduct-based MonadError behavior for EitherT and OptionT.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- scala
- Domain
- backend-api-design
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100