Is there a way to mark a class constructor as priv...

# language-evolution

[Hunter]

Is there a way to mark a class constructor as private-in-file? Currently I have to use internal to get the closest behavior but I really would want it to only be accessible in-file. If not, would be very nice to have.

[Gat Tag]

I wish.....

[Adam S]

best alternative I can think of: create a sealed public type, with a single private implementation.

sealed class FooService {
    abstract val name: String
}

private class FooServiceImpl(
    override val name: String
) : FooService()

val defaultFooService: FooService = FooServiceImpl("default")

[Zach Klippenstein (he/him) [MOD]]

Sealed impls can be in different files in the same source set

[Zach Klippenstein (he/him) [MOD]]

I also wish Kotlin had file private 😔

[komu]

You could have an opt-in annotation that itself is not visible outside the file so no-one else can use it:

@file:OptIn(PrivateToMe::class)

@RequiresOptIn
private annotation class PrivateToMe

@PrivateToMe
fun foo() { }

fun bar() {
    foo()   
}

That said, this does feel a bit wonky and I haven't actually used it anywhere.

I've also found myself often wanting file private access.

[Zach Klippenstein (he/him) [MOD]]

if i'm that worried about other code in the module accessing something, i'd probably just make a new module

[Gat Tag]

For me it is more often just about scope/auto completion pollution, and reminding myself about my own design intentions later on

[CLOVIS]

You could have an opt-in annotation that itself is not visible outside the file so no-one else can use it:

IMO, if you're going to do this, use @Deprecation(level = DeprecationLevel.HIDDEN) so it's not even in the generated documentation, and you don't need a custom annotation

[Adam S]

You could have an opt-in annotation that itself is not visible outside the file so no-one else can use it:

Nitpick: anyone could opt-in via compiler args 😅

kotlin {
  compilerOptions.optIn.add("PrivateToMe")
}

[CLOVIS]

or even just @Suppress("INVISIBLE_REFERENCE") if they're going that far 😅

[Adam S]

technically yes, but that's harder to discover than the documented opt-in flag