Is there way to add one more argument to the function(which has var args) with default value without breaking existing calls?

I have a function

fun foo(
    id: String,
    vararg values: Int,
){
  ...    
}

and there are calls like these

fun bar1(){
    foo("id_1")
    foo("id_2", 1)
    foo("id_3", 1, 2, 3)
}

Now I've understood that I need to add one more argument to foo. but I don't want to break existing calls so I tried to add it with default values:

fun foo(
    id: String,
    attributes: Array<String> = arrayOf("a", "b"),
    vararg values: Int,
){
  ...
}

But

foo("id_2", 1)
foo("id_3", 1, 2, 3)

became broken.

Is there way to add one more argument with default value without breaking existing calls ?

Option 1:

You can, if you move the new parameter to the end:

fun foo(
    id: String,
    vararg values: Int,
    attributes: Array<String> = arrayOf("a", "b"),
) {
    // ...
}

But it becomes a bit awkward to call:

fun bar1() {
    foo("id_1")
    foo("id_2", 1)
    foo("id_3", 1, 2, 3)
    foo("id_3", 1, 2, 3, attributes = arrayOf("a", "b"))
}

You need to specify the parameter name, otherwise the compiler will think the array is still part of the varargs parameter.

Option 2:

You can overload the function:

fun foo(
    id: String,
    vararg values: Int,
) {
    foo(id, arrayOf("a", "b"), *values)
}

fun foo(
    id: String,
    attributes: Array<String>,
    vararg values: Int,
) {
    // ...
}

Then you can call it like this:

fun bar1() {
    foo("id_1")
    foo("id_2", 1)
    foo("id_3", 1, 2, 3)
    foo("id_3", arrayOf("a", "b"), 1, 2, 3)
}

This is more elegant at the call site but you have a little overhead at the declaration side.