Support custom error types

[matt-ramotar]

Hello :spock-hand: ! Does someone have any guidance/sample project on how to handle network/http errors with Store? Currently the network layer in our Android app takes care of catching exceptions, parsing error payloads and returning a custom monad class like Result<NetworkError, T>> . Looking at StoreReadResponse it seems that using Throwable or String is the only way to go. Thanks for your answers!

https://kotlinlang.slack.com/archives/C06007Z01HU/p1699457424194509

[matt-ramotar]

@digitalbuddha We would need to fix tests obviously but I wanted to get something up first for discussion. Adding a generic to StoreReadResponse and FetcherResult would introduce breaking changes I know we don't want. Thoughts?

[borsini]

@matt-ramotar thanks for bringing up implementation ideas so quickly. Would it be possible for the Custom error to accept any type instead of only Throwable? As an example, our network layer uses a sealed interface with no Throwable inheritance. Something like this

sealed interface NetworkError { 
    data class StatusCodeError(val statusCode: Int, val error: CustomApiError?) : NetworkError
    data class UnknownError(val throwable: Throwable) : NetworkError
    data object NetworkUnavailableError : NetworkError
}

[matt-ramotar]

@borsini Seems fine to me 👍🏽

[yigit]

lgtm but we should add a test ideally :)

[borsini]

Hello @matt-ramotar, I checked how this PR was doing and came up with an idea. I created this little draft PR to illustrate my thinking. What if, instead of having a sealed hierarchy, Store use only one generic Error type.

Let me know what you think 😄

[matt-ramotar]

Sorry to be slow @borsini, will try to get this merged by end of week

[borsini]

No worries @matt-ramotar this is open source 🙂