KSP2 version 2.1.20-RC-1.0.30 crashes with NoSuchElementException: Collection contains no element matching the predicate

[rjaros]

After migration from KSP1 to KSP2 I have a problem when I try to read a parameter of an annotation on a class, which has a default value. The annotation is defined like this:

@Target(AnnotationTarget.CLASS)
public annotation class SimpleHtmlComponent(val tagName: String, val withText: Boolean = false)

and the code of the processor looks like this:

val simpleHtmlComponent = classDeclaration.getAnnotationsByType(SimpleHtmlComponent::class).first()
val tagName = simpleHtmlComponent.tagName
val withText = simpleHtmlComponent.withText

The last line throws the exception:

Caused by: java.util.NoSuchElementException: Collection contains no element matching the predicate.
        at com.google.devtools.ksp.UtilsKt.createInvocationHandler$lambda$8(utils.kt:587)
        at jdk.proxy10/jdk.proxy10.$Proxy212.withText(Unknown Source)
        at dev.kilua.ksp.KiluaProcessor.process(KiluaProcessor.kt:62)
        at com.google.devtools.ksp.impl.KotlinSymbolProcessing$execute$1$1.invoke(KotlinSymbolProcessing.kt:581)
        at com.google.devtools.ksp.impl.KotlinSymbolProcessing$execute$1$1.invoke(KotlinSymbolProcessing.kt:579)
        at ksp.com.google.devtools.ksp.common.IncrementalContextBase.closeFilesOnException(IncrementalContextBase.kt:404)
        at com.google.devtools.ksp.impl.KotlinSymbolProcessing.execute(KotlinSymbolProcessing.kt:579)
        at com.google.devtools.ksp.impl.KSPLoader$Companion.loadAndRunKSP(KSPLoader.kt:37)
        at com.google.devtools.ksp.impl.KSPLoader.loadAndRunKSP(KSPLoader.kt)

To reproduce:

1. Clone https://github.com/rjaros/kilua project
2. Checkout ksp2issue branch
3. Run ./gradlew allTest --stacktrace
4. See the crash

The annotations are in the modules/kilua-annotations module. The processor in the plugins/kilua-ksp-processor module.

The same code works fine with KSP1.

[ting-yuan]

The exception happened when it tries to get the default value of the annotation in a KMP build. It works on KSP1 by accident, where 1) JVM is part of the targets, and 2) KSP1 didn't check the targets and unconditionally tries to load the annotation as a Java class instance. Therefore it works when JVM is present in KSP1.

In KMP, annotation default values from libraries are generally not available other than the JVM platform. We are awaiting the fix in the compiler: https://youtrack.jetbrains.com/issue/KT-59526/Store-annotation-default-values-in-metadata-on-JVM (ignore the -on-JVM part of the description.)