Multiple ensures used to validate the same var does not raise errors

[0bon]

Arrow versions/libs:

implementation('io.arrow-kt:arrow-fx-coroutines-jvm:2.0.0')
implementation('io.arrow-kt:arrow-core-jvm:2.0.0')
implementation('io.arrow-kt:arrow-core-high-arity:2.0.0')

When doing multiple ensure checks for the same variable, if an error condition arises, it is not raised and collected.

See code below

sealed class interface BookProblem {
    data object BookTypeIsRequired: BookProblem
    data object BookTypeCannotBeLarge: BookProblem
}

enum class BookType {
    None,
    Large,
    Small
}

data class Book(val type: BookType, ) {
    companion object {

        fun create(type: BookType) = either {
            zipOrAccumulate(
                { ensure(type != BookType.None) { BookProblem.BookTypeIsRequired } },
                { ensure(type != BookType.Large) { BookProblem.BookTypeCannotBeLarge } },
            ) { _, _ ->
                Book(type)
            }
        }
    }
}

Doing two ensure checks on the type variable does not return a NonEmptyList(BookProblem) if one of the conditions fails i.e. if type == BookType.None the error will not be raised and the code will assume the variable is valid and proceed to create the Book object.

The following code fixes the issue but forces me to use only one BookProblem to describe two different types of errors:

        fun create(type: BookType) = either {
            zipOrAccumulate(
                { ensure(type != BookType.None && ensure(type != BookType.Large) { BookProblem.BookTypeIsRequired } },
            ) { _ ->
                Book(type)
            }
        }

[kyay10]

Your second code block seems to have syntax errors, so I'm struggling to decipher what it does

[0bon]

Working code below:

import arrow.core.EitherNel
import arrow.core.raise.either
import arrow.core.raise.ensure
import arrow.core.raise.zipOrAccumulate

sealed interface BookProblem {
    data object BookTypeIsRequired: BookProblem
    data object BookTypeCannotBeLarge: BookProblem
}

enum class BookType {
    None,
    Large,
    Small
}

data class Book(val type: BookType, ) {
    companion object {
        fun create(type: BookType): EitherNel<BookProblem, Book> = either {
            zipOrAccumulate(
                { ensure(type != BookType.None) { BookProblem.BookTypeIsRequired } },
                { ensure(type != BookType.Large) { BookProblem.BookTypeIsRequired } }
            ) { _, _  ->
                Book(type)
            }
        }
    }
}