mutable type in collection

[xiaozhikang0916]

Fix #81

Now items of list/set can be modified like issue #81 shows.

Map and generic type of non-primitive are currently not supported.

[serras]

@xiaozhikang0916 thanks for your contribution! This looks fantastic, let's check that CI is green and then I'll merge

[xiaozhikang0916]

The lint issue is fixed.

And, there will be some break change in this pr.

@Test
fun `edit list item in old school style`() {
  """
    data class Group(val p: List<Person>)
    data class Person(val age: Int)
    
    val g1 = Group(listOf(Person(1), Person(2)))
    val g2 = g1.copy { p[1] = p[1].copy(age = 3) }
    val age = g2.p[1].age
  """.trimIndent().evals("age" to 3)
}

This test will fail in this pr but pass in the main branch.

[serras]

This test will fail in this pr but pass in the main branch.

why is it so? Is it because the copy method no longer exists or some other reason?

[xiaozhikang0916]

This test will fail in this pr but pass in the main branch.

why is it so? Is it because the copy method no longer exists or some other reason?

    data class Group(val p: List<Person>)
    data class Person(val age: Int)

In main branch, you will get a mutable class of Group like

public class `Group$Mutable`(
  public var p: MutableList<Person>,
  public val old: Group,
)

Inside the copy scope, p[1] returns a instance of Person class, which is a kotlin data class so you can call the copy function.

---

In this pr, the mutable class of Group becomes

public class `Group$Mutable`(
  public var p: MutableList<`Person$Mutable`>,
  public val old: Group,
)

In the copy scope, p[1] will return the generated mutable class of Person rather than the original data class, which means, no copy function avaliable.

---

This is an intended change, but also break change. All data access operation of list/set inside a copy scope should have a check, and call of copy function should migrate to value-assign style.