Spring Fix handling value class with private constructor on proxy

Problem

CoroutineUtils and InvocableHandlerMethod will throw exception when value class whose constructor is private is given like

@JvmInline
value class ValueClassWithPrivateConstructor private constructor(val value: String) {
    companion object {
        fun from(value: String) = ValueClassWithPrivateConstructor(value)
    }
}

stacktrace

java.lang.IllegalAccessException: class kotlin.reflect.jvm.internal.calls.CallerImpl$Method cannot access a member of class org.springframework.core.CoroutinesUtilsTests$ValueClassWithPrivateConstructor with modifiers "private static"
kotlin.reflect.full.IllegalCallableAccessException: java.lang.IllegalAccessException: class kotlin.reflect.jvm.internal.calls.CallerImpl$Method cannot access a member of class org.springframework.core.CoroutinesUtilsTests$ValueClassWithPrivateConstructor with modifiers "private static"
    at kotlin.reflect.jvm.internal.KCallableImpl.call(KCallableImpl.kt:280)
    at org.springframework.core.CoroutinesUtils.lambda$invokeSuspendingFunction$3(CoroutinesUtils.java:135)
    at kotlin.coroutines.intrinsics.IntrinsicsKt__IntrinsicsJvmKt$createCoroutineUnintercepted$$inlined$createCoroutineFromSuspendFunction$IntrinsicsKt__IntrinsicsJvmKt$4.invokeSuspend(IntrinsicsJvm.kt:270)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:367)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:30)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable$default(Cancellable.kt:25)
    at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:110)
    at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:126)
    at kotlinx.coroutines.reactor.MonoKt.monoInternal$lambda$2(Mono.kt:92)
    at reactor.core.publisher.MonoCreate.subscribe(MonoCreate.java:61)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4568)
    at kotlinx.coroutines.reactor.MonoKt.awaitSingleOrNull(Mono.kt:47)
    at org.springframework.core.CoroutinesUtilsTests$invokeSuspendingFunctionWithValueClassWithPrivateConstructorParameter$1.invokeSuspend(CoroutinesUtilsTests.kt:216)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:108)
    at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:280)
    at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:85)
    at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
    at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
    at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38)
    at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
    at org.springframework.core.CoroutinesUtilsTests.invokeSuspendingFunctionWithValueClassWithPrivateConstructorParameter(CoroutinesUtilsTests.kt:215)
    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
Caused by: java.lang.IllegalAccessException: class kotlin.reflect.jvm.internal.calls.CallerImpl$Method cannot access a member of class org.springframework.core.CoroutinesUtilsTests$ValueClassWithPrivateConstructor with modifiers "private static"
    at java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Reflection.java:392)
    at java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:674)
    at java.base/java.lang.reflect.Method.invoke(Method.java:560)
    at kotlin.reflect.jvm.internal.calls.CallerImpl$Method.callMethod(CallerImpl.kt:97)
    at kotlin.reflect.jvm.internal.calls.CallerImpl$Method$Static.call(CallerImpl.kt:106)
    at kotlin.reflect.jvm.internal.calls.ValueClassAwareCaller.call(ValueClassAwareCaller.kt:199)
    at kotlin.reflect.jvm.internal.KCallableImpl.call(KCallableImpl.kt:108)
    ... 25 more

Solution

use KCallablesJvm.setAccessible before creating object to avoid the exception

Concern

in this PR, i modified three places. those of them are same. is it better to extract them into a single method?

Comment From: quaff

Does it add overhead and is it worthy if it does?

Comment From: T45K

hmm, maybe so but i don't know how heavy it is... let me measure it. is there any benchmark?

anyway, i think this private constructor issue is regression and should be fixed

Comment From: T45K

let me share my initial and rough investigation

i wrote the following test code to measure invoking time by using Kotlin measureNanoTime

@Test
fun measure() {
    val method =
        CoroutinesUtilsTests::class.java.declaredMethods.first { it.name.startsWith("suspendingFunctionWithValueClass") }
    println(measureNanoTime {
        repeat(1_000_000) {
            CoroutinesUtils.invokeSuspendingFunction(method, this, "foo", null)
        }
    })
}

in CoroutinesUtilsTests.

and then, i executed the test five times on each of w/o setAccessible (i.e., comment out KCallablesJvm.setAccessible(valueClassConstructor, true);) and w/ setAccessible

this is the results (unit: nano sec)

	1st	2nd	3rd	4th	5th
w/o setAccessible	2,855,264,875	2,724,373,625	1,360,412,625	1,330,190,917	2,604,268,917
w/ setAccessible	1,290,038,333	2,573,693,666	2,516,409,792	2,744,773,333	1,369,282,958

both execution time is around 1.3 sec or 2.7 sec, and there seems no big performance issue