How do I find check if a constructor parameter is also a pro kotlinlang #reflect

We consider being declared in a primary constructor an internal implementation detail of a property, so there's no information in the binary metadata to differentiate between

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class A(val x: String)

and

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class A(x: String) {
    val x: String = x
}

dstarcev

04/19/2018, 10:03 AM

How do I differentiate

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class A(x: String) {
    val x: String = x
}

and

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class A(x: String) {
    val x: String = "not x"
}

udalov

04/19/2018, 10:06 AM

You can't do that either, because of the reason I described. Basically, to the outside observer, a class has primary constructor parameters and properties but it cannot tell how they are related. But this is not a bug, it's by design at the moment. Do you have a use case where it's necessary to know if a property is declared in the constructor?

dstarcev

04/19/2018, 10:08 AM

Obfuscating a class I want to keep the same names for parameters of the primary constructor and their according properties if such

otherwise kotlin reflection will be broken on the class, as @Eugenio said in another thread

or at least tools such as Jackson that may rely on these names may break

udalov

04/19/2018, 10:11 AM

No, the question in that thread was whether Kotlin reflection would break if the property name differs from the backing field name (at least that's what I was answering :) ). Nothing would break if the property name differs from the "related" primary constructor parameter name, because as I said, there's no information on that relation after the class is compiled, so no tool can rely upon it

Eugenio

04/19/2018, 1:45 PM

Isn't there a way to keep the parameter names when compiling for Java8?

udalov

04/19/2018, 2:16 PM

There is (

-java-parameters

), but I don't see how it's relevant to this discussion because here only the Kotlin metadata is affected

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