Scala - avoid override of a super class field in the copy method - scala

Question

Let's say for instance that I have the following classes, is there a way to do the copy command without overriding the argument from the superclass?
I want to avoid override val arg1: String from the declaration of - case class MyCaseClass(override val arg1: String, arg2: String) extends MyAbstractClass
abstract class MyAbstractClass (val arg1: String = "bar 1")
case class MyCaseClass(arg2: String) extends MyAbstractClass
object MyMain {
def main(args: Array[String]): Unit = {
val myObj = MyCaseClass(arg2 = "bar 2")
println("a.arg1: " + myObj.arg1) // a.arg1: bar 1
println("a.arg2: " + myObj.arg2) // a.arg2: bar 2
val b = myObj.copy(arg1 = "try_1", arg2 = "try_2")
//>> "too many arguments (2) for method copy: (arg2: String)com.MyCaseClass
//>> Note that 'arg1' is not a parameter name of the invoked method."
}
}
Edit:
In my actual code I got hundreds of fields, that's why it's so important, I want to keep clean code and avoid hundreds of meaningless redundant overrides.

Answer 1

An alternative would be to NOT provide a value to arg1
trait MyAbstractClass {
val arg1: String // no value assigned...
}
case class MyCaseClass(
arg1: String = "bar 1", // ...no need for override val
arg2: String
) extends MyAbstractClass
Then
val myObj = MyCaseClass(arg2 = "bar 2")
println("a.arg1: " + myObj.arg1) // a.arg1: bar 1
println("a.arg2: " + myObj.arg2) // a.arg2: bar 2
val b = myObj.copy(arg1 = "try_1", arg2 = "try_2")
works without any issue. The only difference is that default value would have to be provided for arg1 in MyCaseClass constructor.
If you don't want to make arg1 a part of:
MyCaseClass.apply
MyCaseClass.unapply
myCaseClass.toString
myCaseClass.equals(anotherObject)
myCaseClass.hashcode
then probably using a case class is a bad idea in the first place, since case class is less of a "universal boilerplate generator" and more like a build-in way of defining records with a strong opinion what a record is. And there are alternatives to it like e.g. contraband with different opinions and decisions.

Answer 2

As #Mateusz Kubuszok suggested, that's might be the only option, which obviously doesn't make the code cleaner.
abstract class MyAbstractClass (val arg1: String = "bar 1")
case class MyCaseClass(val arg2: String) extends MyAbstractClass {
def copy(newArg1: String, newArg2: String): MyCaseClass =
new MyCaseClass(arg2 = newArg2) {
override val arg1: String = newArg1
}
}
object MyMain {
def main(args: Array[String]): Unit = {
val myObj = MyCaseClass(arg2 = "bar 2")
println("myObj.arg1: " + myObj.arg1) // myObj.arg1: bar 1
println("myObj.arg2: " + myObj.arg2) // myObj.arg2: bar 2
val mySecObj = myObj.copy(newArg1 = "try_1", newArg2 = "try_2")
println("mySecObj.arg1: " + mySecObj.arg1) // mySecObj.arg1: try_1
println("mySecObj.arg2: " + mySecObj.arg2) // mySecObj.arg2: try_2
}
}