22 fields limit in Scala 2.11 + Play Framework 2.3 Case classes and functions

Question

Scala 2.11 is out and the 22 fields limit for case classes seems to be fixed (Scala Issue, Release Notes).

This has been an issue for me for a while because I use ca

Answer 1

It seems this handles it all nicely.

+22 field case class formatter and more for play-json https://github.com/xdotai/play-json-extensions

Supports Scala 2.11.x, 2.12.x, and 2.13.x and play 2.3, 2.4, 2.5 and 2.7

And is referenced in the play-json issue as the preferred solution (but not yet merged)

Answer 2

You can use Jackson's Scala module. Play's json feature is built upon Jackson scala . I don't know why they put a 22 field limit here while jackson supports more than 22 fields. It may make sense that a function call can never use more than 22 parameters, but we can have hundreds of columns inside a DB entity, so this restriction here is ridiculous and makes Play a less productive toy. check this out:

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule

object JacksonUtil extends App {
  val mapper = new ObjectMapper with ScalaObjectMapper
  mapper.registerModule(DefaultScalaModule)


  val t23 = T23("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w")

  println(mapper.writeValueAsString(t23))
 }
case class T23(f1:String,f2:String,f3:String,f4:String,f5:String,f6:String,f7:String,
    f8:String,f9:String,f10:String,f11:String,f12:String,f13:String,f14:String,f15:String,
    f16:String,f17:String,f18:String,f19:String,f20:String,f21:String,f22:String,f23:String)