test.scala

import sangria.schema._
import sangria.execution._
import sangria.marshalling.sprayJson._
import sangria.parser.QueryParser
import spray.json._
import scala.concurrent.duration._
import scala.concurrent.Await
import scala.concurrent.ExecutionContext.Implicits.global
import sangria.macros.derive.deriveInputObjectType

case class Ctx()
case class ContactInput(id: Int, name: String, email: Option[String])

object MyJsonProtocol extends DefaultJsonProtocol {
  implicit val contactInput = jsonFormat3(ContactInput.apply)
}

import MyJsonProtocol._

// The schema
val ContactInputType: InputType[ContactInput] = deriveInputObjectType[ContactInput]()
val submit: Field[Ctx, Unit] = Field("submit", StringType,
  arguments = List(
    Argument(
      "contacts",
      ListInputType(ContactInputType),
    )
  ),
  resolve = c => "hello" + c.arg("contacts")
)

val Mutation: ObjectType[Ctx, Unit] = ObjectType("Mutation", fields[Ctx, Unit](submit))
val Query: ObjectType[Ctx, Unit] = ObjectType("Query", fields[Ctx, Unit](
  Field("hello", StringType, resolve = _ ⇒ "Hello world!")
))
val schema = Schema(Query, Some(Mutation))

// Test mutation
val query = """
  mutation SaveChanges ($contacts: [ContactInput!]!) {
    submit(contacts: $contacts)
  }
"""

val vars = """{
  "contacts": [{
      "id": 1,
      "name": "Foo",
      "email": "foo@localhost"
    },
    {
      "id": 2,
      "name": "Bar",
      "email": "bar@localhost"
  }]
}""".parseJson.asJsObject()

val result = Executor.execute(
  schema,
  QueryParser.parse(query).get,
  userContext = Ctx(),
  variables = vars
)
println(Await.result(result, 10.seconds))

// Expected output:
//
//   {
//     "hello": "helloVector(...."
//   }

// Actual output:
// 
// java.lang.ClassCastException: scala.collection.immutable.Vector cannot be cast to spray.json.JsValue
//	at sangria.marshalling.sprayJson$$anon$2.fromResult(scratch.scala:99)
//	at sangria.execution.ValueCollector$.$anonfun$getArgumentValues$6(scratch.scala:86)
//	at sangria.execution.ValueCoercionHelper.resolveMapValue(scratch.scala:126)
//	at sangria.execution.ValueCollector$.$anonfun$getArgumentValues$4(scratch.scala:87)
//	at #worksheet#.#worksheet#(scratch.scala:118)