jsonSchema generation for classes extending TraversableOnce return { type: array }

[kolia]

The jsonSchema returned for:

  case class WorkingClass(int: Int) {
    def iterator: Iterator[Int] = List().toIterator
  }

looks correct:

{
  "type" : "object",
  "id" : "urn:jsonschema:com:ccri:commons:config:schema:ReproduceIssue:WorkingClass",
  "properties" : {
    "int" : {
      "type" : "integer"
    }
  }
}

But if the class is declared as extending Iterable[Int]

  case class FailingClass(int: Int) extends Iterable[Int] {
    def iterator: Iterator[Int] = List().toIterator
  }

I get:

{
  "type" : "array"
}

As far as I can tell, mixing in any trait that subclasses TraversableOnce produces {"type": "array"}.

To reproduce:

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.jsonSchema.customProperties.ValidationSchemaFactoryWrapper
import com.fasterxml.jackson.module.jsonSchema.factories.SchemaFactoryWrapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper


object JacksonHelper {
  val jacksonObjectMapper: ObjectMapper = new ObjectMapper() with ScalaObjectMapper
  jacksonObjectMapper.registerModule(DefaultScalaModule)

  val writer = jacksonObjectMapper.writer()

  val visitor: SchemaFactoryWrapper = new ValidationSchemaFactoryWrapper()

  val prettyPrinter = jacksonObjectMapper.writerWithDefaultPrettyPrinter()

  def jsonSchema(c: Class[_]) = {
    writer.acceptJsonFormatVisitor(c, visitor)
    val jsonSchema = visitor.finalSchema()
    prettyPrinter.writeValueAsString(jsonSchema)
  }
}

object ReproduceIssue extends App {

  case class WorkingClass(int: Int) {
    def iterator: Iterator[Int] = List().toIterator
  }

  case class FailingClass(int: Int) extends Iterable[Int] {
    def iterator: Iterator[Int] = List().toIterator
  }

  println("WorkingClass:")
  println(JacksonHelper.jsonSchema(classOf[WorkingClass]))
  println("FailingClass:")
  println(JacksonHelper.jsonSchema(classOf[FailingClass]))
}

        <dependency>
            <groupId>com.fasterxml.jackson.module</groupId>
            <artifactId>jackson-module-jsonSchema</artifactId>
            <version>2.6.3</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.module</groupId>
            <artifactId>jackson-module-scala_2.10</artifactId>
            <version>2.6.3</version>
        </dependency>

Am I doing something wrong, is this not supposed to work, or is it a bug?

[pjfanning]

jackson-module-jsonSchema support is deprecated and due for removal when jackson 3 is released