poslegm/brief

Automated case classes validation using refinement types and macros

brief's Issues

Add field name to error message

It should works like:

@Validation
case class Test(a: Int, b: Int Refined Positive)
Test.create(1, -2) // Validated.Invalid(NonEmptyChain("For field Test.b: Predicate failed: (-2 > 0)."))

It can be done here

Cross build for Scala 2.11 and 2.12

meh...

Publish to Maven Central

• Add sbt-ci-release
• Choose package and organization name. I don't want to have "com.github.poslegm" %% "brief" % "version" or "dev.chugunkov" %% "brief" % "version" in build.sbt
• Follow steps from plugin README

Custom error types

It should works like:

@Validation case class Test(a: Int Refined Positive)
Test.create(-2) // Left(List("bla bla"))

final case class CustomException(msgs: List[String] Refined NonEmpty)
  extends Exception(s"validation errors on CustomTest creation: ${msgs.mkString("[", ",", "]")}")
  with NoStackTrace
@Validation(CustomException(_)) case class CustomTest(a: Int Refined Positive)
Test.create(-2) // Left(CustomException("validation errors on CustomTest creation: [bla bla]"))

Ideally accept custom lambda into macro annotation:

@scala.annotation.compileTimeOnly("enable macro paradise to expand macro annotations")
class Validation[E](
  mapErrors: List[String] Refined NonEmpty => E = (errors: List[String] Refined NonEmpty) => errors
) extends scala.annotation.StaticAnnotation {
  def macroTransform(annottees: Any*): Any = macro ValidationMacros.apply
}

Add Scala Steward

https://github.com/scala-steward-org/scala-steward

Support type aliases

  test("work with type alias") {
    type PositiveInt = Int Refined Positive
    @Validation case class Test(a: PositiveInt)
    // compilation fails
    assertEquals(Test.create(2), Validated.valid(Test(2))) 
    assertEquals(
      Test.create(-2),
      Validated.invalidNec[String, Test]("For field Test.ref: Predicate failed: (-2 > 0).")
    )
  }

create argument has type PositiveInt instead of int

Configure CI

• Use GH Actions (sample)
• Check tests and formatting

Support Scala 3

It will be an entertaining adventure

Write documentation in README

1. Motivation
2. More complicated examples
3. Installation guide (maven link, sbt copy-paste line)
4. Future goals
5. Current limitations, supported Scala versions

Enable compilation warnings

-deprecation, etc
As many as possible

Support generic case classes

@Validation case class Test[T](a: T) // <- doesn't compile

Type parameters with their constraints should be propagated to generated create method parameters and argument types.

Support complex predicates

@Validation case class(a: String Refined IPv4 Or IPv6) // <- doesn't compile

It fails here

Get rid of cats.data.Validated

Validated is ok for proof of concept but it requires extra dependency on cats-core. There is no need to use it in external API.

1. Change external API returning type to Either[List[String] Refined NonEmpty, C]
2. Use self-made Validated or other error accumulation technique inside
3. Remove cats-core from deps