[0.5.27 regression] serializedSize does not work with java serialization

[eiennohito]

Do not use 0.5.27, 0.5.28 if you serialize case classes with java serialization and then serialize them as protobufs.

I am working on the fix.

[eiennohito]

Reproducible as:

  def checkJavaSerialization[T <: GeneratedMessage](a: T) = {
    val baos = new ByteArrayOutputStream()
    val oos = new ObjectOutputStream(baos)

    oos.writeObject(a)
    oos.close()

    val ois = new ObjectInputStream(new ByteArrayInputStream(baos.toByteArray))
    val b = ois.readObject().asInstanceOf[T]
    val abytes = a.toByteArray
    val bbytes = b.toByteArray //crashes here

    abytes mustBe bbytes
  }

Stacktrace like:

com.google.protobuf.CodedOutputStream$OutOfSpaceException: CodedOutputStream was writing to a flat byte array and ran out of space.
    at com.google.protobuf.CodedOutputStream.refreshBuffer(CodedOutputStream.java:990)
    at com.google.protobuf.CodedOutputStream.writeRawByte(CodedOutputStream.java:1069)
    at com.google.protobuf.CodedOutputStream.writeRawByte(CodedOutputStream.java:1078)
    at com.google.protobuf.CodedOutputStream.writeRawVarint32(CodedOutputStream.java:1231)
    at com.google.protobuf.CodedOutputStream.writeTag(CodedOutputStream.java:1216)
    at com.google.protobuf.CodedOutputStream.writeString(CodedOutputStream.java:233)
    at com.trueaccord.proto.e2e.repeatables.RepeatablesTest$$anonfun$writeTo$4.apply(RepeatablesTest.scala:45)
    at com.trueaccord.proto.e2e.repeatables.RepeatablesTest$$anonfun$writeTo$4.apply(RepeatablesTest.scala:44)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at com.trueaccord.proto.e2e.repeatables.RepeatablesTest.writeTo(RepeatablesTest.scala:44)
    at com.trueaccord.scalapb.GeneratedMessage$class.toByteArray(GeneratedMessageCompanion.scala:81)
    at com.trueaccord.proto.e2e.repeatables.RepeatablesTest.toByteArray(RepeatablesTest.scala:11)
    at JavaSerializationSpec.checkJavaSerialization(JavaSerializationSpec.scala:33)