All modules: importing derivation.instances.given can cause an issue as it overrides all type-classes defined in the companion objects

[kevin-lee]

Summary

All modules: importing derivation.instances.given can cause an issue as it overrides all type-classes defined in the companion objects

Version

0.5.0 but all other versions with modules containg derivation.instances

Scala Version

3

Java Version

n/a

Description

Given

import cats.*
import io.circe.*

import refined4s.modules.circe.derivation.instances.given
import java.time.Instant

final case class Response(created: Response.Created) derives Codec.AsObject

object Response {
  type Created = Created.Type
  object Created extends Newtype[Instant] {

    inline given createdEncoder: Encoder[Created] =
      Encoder[Long].contramap(_.value.getEpochSecond)

    inline given createdDecoder: Decoder[Created] =
      Decoder[Long].map(Instant.ofEpochSecond).map(Created(_))
  }
}

When encoding the Response, it generates JSON like

{
  "created": "2023-12-23T12:07:03Z"
}

but the expected one should be

{
  "created": 1703333223
}

How to Reproduce

Check out the description

Possible Cause

It looks like the Encoder and Decoder from import refined4s.modules.circe.derivation.instances.given have higher precedence than the ones defined in the companion object.

Possible Solution

Since the following import is required for the pre-defined types (e.g. NonEmptyString, refined numeric, network types, etc.), this is a very common issue.

import refined4s.modules.circe.derivation.instances.given

So, a possible solution might be to provide explicit type-class instances for the pre-defined types and separate them from the generic one (refined4s.modules.circe.derivation.instances).

---

• [refined4s-circe] Add explicit Encoder and Decoder for pre-defined types #166
• [refined4s-cats] Add explicit Eq and Show for pre-defined types #171
• [refined4s-pureconfig] Add explicit ConfigReader and ConfigWriter for pre-defined types #172
• [refined4s-doobie] Add explicit Get and Put for pre-defined types #173