Hi everyone! Does anyone know how to get the “default value” from a constructor parameter using annotation processor and kotlin-metadata? Example:

class Foo(val bar: Int = 1)

how do I get the value

1

?

On the JVM platform, there’s a reflection API function that returns the Kotlin property that corresponds to a field. Is there a way to get the Kolin property that corresponds to the JVM method that is the property’s getter?

I'm trying to load some classes dynamically at runtime, which should all implement a specific interface,

GeneratorPipeline

. Given a String array of class names, I'd like the corresponding array of KClass objects. But this fails on line 7

processorPipeline.add(kClass)

as

kClass

is of type

KClass<out Any!>

. Any ideas? Loosening the array

processorPipeline = arrayListOf<KClass<*>>()

is OK, but ultimately I need

Array<KClass<GeneratorPipeline>>

/**
 * JVM internal name of the class, where package names are separated by '/', and class names are separated by '$',
 * for example: `"org/foo/bar/Baz$Nested"`
 */
val ClassName.jvmInternalName: String
    get() =
        if (this.isLocal) substring(1)
        else replace('/', '$')

Isn't it supposed to replace

.

with

$

, not

/

with

$

?

Why does this work:

val m = JSONParser::class.java.getAnnotation(Metadata::class.java)

but this returns `null`:

val m = JSONParser::class.findAnnotation<Metadata>()

🤔

is it possible to get the kclass for a ktype?

Mutable/Not-Mutable handling of collection classes seems to be very inconsistent:

val x: MutableCollection<String> get() = TODO()
fun main() {
  println(MutableCollection::class) // prints "class kotlin.collections.Collection
  println(Set::class.isSubclassOf(MutableCollection::class)) // prints true, should be false
  println(::foo.returnType) // prints kotlin.collections.MutableCollection<kotlin.String>, yay!
  println(::foo.returnType.classifier) // prints kotlin.collections.Collection, :(
}

Is there any way to figure out if a KType represents a mutable collection type?

Would it be considered a bug that kotlin calculates a different property name for a java class then standard Java Beans properties code does ? Example String getURL() JavaBeans : "URL" Kotlin: "uRL" EDIT: I created KT-29123

I’m looking at the docs of

KFunction

and I’m wondering why only Jvm has

instanceParameter

and

valueParameters

. How does that work on Native? Should I suppose all the

parameters

are valueParameters or maybe it’s just not implemented yet and I should distinct them by myself ( how? ) ? P.S. I don’t know much about Native, that’s the reason of the dumb question

Hey guys, I'm trying to convert a method reference like

SomeClass::main

into a classname for a

java -mainClass

argument. This is the best I've got

private val KFunction<*>.instanceTypeName: String get() {
    return ((this as FunctionReference).boundReceiver::class as KClass<*>).jvmName
}

usage:

val mainClass: String = (MyType::main).instanceTypeName

is there a better solution?

What I'm really trying to do is to get a

KFunction0

by applying a receiver to a

KFunction1

returned from

this::class::memberFunctions

- is that possible?

Unfortunately there are not many reflection capabilities for JS yet and same for Native.

seems like whenever i want to pass a DataFrame to something using reflection, this happens:

Exception in thread "main" java.lang.IllegalArgumentException: object is not an instance of declaring class
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

Hi, how to obtain all functions that have a functional parameter using Kotlin Reflect? I tried something like

Class.forName("myClass").declaredMethods.map { it.kotlinFunction!! }.filter { fn -> fn.parameters.any { it is KFunction<*> } }

but it didn't work

How would you instantiate a data class (probably with val) if you have the property names as string and the values with the correct type? I can't wrap my mind around it

🎉 looks like

typeOf

is coming soon 😄 Goodbye type tokens! https://youtrack.jetbrains.com/issue/KT-29915#focus=streamItem-27-3323738.0-0

How do I reflectively instantiate an enum given an enum class of type

java.lang.Class<*>

? Can't find a way to make the type checker happy.

Hey guys, regarding extension functions and reflection, is there a generally accepted solution to "search" for extension functions given you only have an instance? What about an instance and a couple package names?

Is there any smart way to achieve the following?

class MyClass<E: Enum<E>>(val name?) {
    fun read(source: MagicalStringSupplier): E? = source.read()?.let { enumValueOf(it) }
}

I fully understand that the above example does not compile because the type of

E

is a class type parameter that gets erased during runtime. I fully appreciate that there is no way to reify

E

currently, but perhaps there's a more "dirty" way involving passing around a

KClass<E>

or (worst case) even a Java

Class<E>

? We badly need such a feature when reading configurations from files, so that we don't have to constantly convert strings to enums all the time 😇

Hi guys, my setter is not working with private set properties Without the private in the object, works fine

val setter = prop.setter.apply { isAccessible = true } // line 52
setter.call( // line 53
  instance,
  adapter(
    instance,
    prop,
    if (any is Number) fixNumberType(prop, any) else any
  )

Is there anything in the stdlib that captures the class and nullability of a type?

Given an object instance and class is there a way to bind the class member properties to the instance to produce a bound property reference ? E.g. convert a KProperty1 to a KProperty0 Say ``` fun bind( obj: Any ) : List<KProperty0<*>> { val props1= obj::class.memberProperties // KProperty1<T,R> return props.map { bind( it , obj ) ???? } // KProperty0<R> } I can do this: fun bin( knownObject: MyClass ) = listOf( knownObject::prop1 , knownObject::prop2 , ...) But cant find a way to do so generically (without enumerating each property by name/accessor )

hello, does anyone know whether this change was intentional? Java 8 + Kotlin 1.3.31 ->

println({}::class.simpleName)

->

null

Java 8 + Kotlin 1.3.40+ -> automatically generates numeric names

"1"

(and increments it for subsequent anonymous classes) Java 11 ->

null

Does kotlin-reflect-1.3.x have known JDK 11 incompatibilities? Our static analyzer claims it's using JDK APIs that aren't available in 11 (unfortunately I don't have details).

Hello, I'm currently working on a framework, which uses reflection to parse and introspect functions. I'm aware that Kotlin applies type erasure to generics during runtime (effectively turning

SomeClass<Type>

into

SomeClass<*>

). However, I'd expect type checks such as the one outlined below to correctly yield

true

. I'd like to ask if the below code snippet is a mistake on my end or if it's related to some kind of bug related to invariances. Thank you.

Hi! Had to move method from class to extention and now it throws

java.lang.IllegalAccessException: Class clean.db.entities.LocalizationDbEntityKt can not access a member of class infin.api.core.legal.entities.auth.login.LocalizationFromServer with modifiers "private final"

fun LocalizationFromServer.toList() = LocalizationFromServer::class.java.declaredFields.map {
    LocalizationDbEntity(it.name, it.get(this)?.toString())
}

Cah anyone help pls?

Hi! Did I understand it right that kotlin-reflect extracts information about class (for example member names) from its

@Metadata

annotation? Because I can extract class member original names even if ProGuard/R8 has obfusacted the class. Does it make reverse engineering easier because bytecode of the class contains information about its members in

@Metadata

annotation?