Serialization behavior of case objects is different when using scala 2.13 #429
Description
When using scala 2.12.10 it will serialize the fields of the case object. Using scala 2.13.1 it creates an empty object. Test case:
package com.fasterxml.jackson.module.scala.ser
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import org.junit.runner.RunWith
import org.scalatest.FunSuite
import org.scalatestplus.junit.JUnitRunner
@RunWith(classOf[JUnitRunner])
class CaseObjectSerializerTest extends FunSuite {
test("serialize case object") {
val mapper = new ObjectMapper()
mapper.registerModule(DefaultScalaModule)
val json = mapper.writeValueAsString(CaseObjectExample)
assert(json === """{"field1":"test","field2":42}""")
}
}
case object CaseObjectExample {
val field1: String = "test"
val field2: Int = 42
}Results:
$ sbt ++2.12.10 "testOnly *CaseObjectSerializerTest*"
[info] CaseObjectSerializerTest:
[info] - serialize case object
[info] Run completed in 450 milliseconds.
[info] Total number of tests run: 1
[info] Suites: completed 1, aborted 0
[info] Tests: succeeded 1, failed 0, canceled 0, ignored 0, pending 0
[info] All tests passed.
[success] Total time: 23 s, completed Sep 19, 2019 11:13:53 AM
$ sbt ++2.13.1 "testOnly *CaseObjectSerializerTest*"
[info] CaseObjectSerializerTest:
[info] - serialize case object *** FAILED ***
[info] "{[]}" did not equal "{["field1":"test","field2":42]}" (CaseObjectSerializerTest.scala:15)
[info] Run completed in 370 milliseconds.
[info] Total number of tests run: 1
[info] Suites: completed 1, aborted 0
[info] Tests: succeeded 0, failed 1, canceled 0, ignored 0, pending 0
[info] *** 1 TEST FAILED ***
[error] Failed tests:
[error] com.fasterxml.jackson.module.scala.ser.CaseObjectSerializerTest
[error] (test:testOnly) sbt.TestsFailedException: Tests unsuccessful
[error] Total time: 2 s, completed Sep 19, 2019 11:16:50 AM