Spring IncompleteAnnotationException with @AliasFor on MessageMapping#value with Kotlin

Affects: Spring Boot 2.4.4

---

build.gradle.kts:

...
    implementation("org.springframework.boot:spring-boot-starter-rsocket")
...

When one has this:

...
@Controller
@MessageMapping
annotation class RSocketController(
    @get:AliasFor(annotation = MessageMapping::class)
    val value: String
)

and this:

...
@RSocketController("reader")
class Reader(
    private val cellRepository: CellRepository,
) {

    @MessageMapping("get-rows-count-in-a-sheet")
    suspend fun getRowsCountInASheet(dto: GetRowsCountInASheetDto): Long = coroutineScope {
...

Then one gets the aforementioned (in the subject) exception. But one must say that this:

...
@Validated
@RequestMapping
@RestController
annotation class ApiController(
    @get:AliasFor(annotation = RequestMapping::class)
    val value: String = ""
)

does not incur any issues.

The stack trace:

...
Caused by: java.lang.annotation.IncompleteAnnotationException: kz.qbi.cells.meta.RSocketController missing element value
    at java.base/sun.reflect.annotation.AnnotationInvocationHandler.invoke(AnnotationInvocationHandler.java:83)
    at com.sun.proxy.$Proxy77.value(Unknown Source)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:282)
    at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:266)
    at org.springframework.core.annotation.TypeMappedAnnotation.getValue(TypeMappedAnnotation.java:394)
    at org.springframework.core.annotation.TypeMappedAnnotation.getValue(TypeMappedAnnotation.java:365)
    at org.springframework.core.annotation.TypeMappedAnnotation.getAttributeValue(TypeMappedAnnotation.java:350)
    at org.springframework.core.annotation.AbstractMergedAnnotation.getValue(AbstractMergedAnnotation.java:178)
    at org.springframework.core.annotation.SynthesizedMergedAnnotationInvocationHandler.lambda$getAttributeValue$1(SynthesizedMergedAnnotationInvocationHandler.java:218)
    at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1705)
    at org.springframework.core.annotation.SynthesizedMergedAnnotationInvocationHandler.getAttributeValue(SynthesizedMergedAnnotationInvocationHandler.java:216)
    at org.springframework.core.annotation.SynthesizedMergedAnnotationInvocationHandler.invoke(SynthesizedMergedAnnotationInvocationHandler.java:90)
    at com.sun.proxy.$Proxy103.value(Unknown Source)
    at org.springframework.messaging.rsocket.annotation.support.RSocketMessageHandler.getCondition(RSocketMessageHandler.java:313)
    at org.springframework.messaging.handler.annotation.reactive.MessageMappingMessageHandler.getMappingForMethod(MessageMappingMessageHandler.java:279)
    at org.springframework.messaging.handler.annotation.reactive.MessageMappingMessageHandler.getMappingForMethod(MessageMappingMessageHandler.java:84)
    at org.springframework.messaging.handler.invocation.reactive.AbstractMethodMessageHandler.lambda$detectHandlerMethods$0(AbstractMethodMessageHandler.java:335)
    at org.springframework.core.MethodIntrospector.lambda$selectMethods$0(MethodIntrospector.java:74)
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:364)
    at org.springframework.core.MethodIntrospector.selectMethods(MethodIntrospector.java:72)
    at org.springframework.messaging.handler.invocation.reactive.AbstractMethodMessageHandler.detectHandlerMethods(AbstractMethodMessageHandler.java:334)
    at org.springframework.messaging.handler.invocation.reactive.AbstractMethodMessageHandler.initHandlerMethods(AbstractMethodMessageHandler.java:308)
    at org.springframework.messaging.handler.invocation.reactive.AbstractMethodMessageHandler.afterPropertiesSet(AbstractMethodMessageHandler.java:260)
    at org.springframework.messaging.handler.annotation.reactive.MessageMappingMessageHandler.afterPropertiesSet(MessageMappingMessageHandler.java:238)
    at org.springframework.messaging.rsocket.annotation.support.RSocketMessageHandler.afterPropertiesSet(RSocketMessageHandler.java:286)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782)
    ... 85 more

Comment From: yerzhant

Tried this:

...
@Controller
@MessageMapping("")
annotation class RSocketController(
    @get:AliasFor(annotation = MessageMapping::class)
    val value: String = ""
)

didn't help either.

Comment From: snicoll

That looks like a Kotlin issue to me. Have you tried

@get:AliasFor(annotation = MessageMapping::class, attribute = "value")

Comment From: yerzhant

Thanks for the reply. No, I guess I haven't. Actually I'm not working on that project any more. Maybe the issue can be closed as it lost its actuality?

Comment From: snicoll

Alright, given the Kotlin-specific issue and the fact that there are issues that have been fixed in Kotlin in the meantime, I tend to agree. If someone else has the issue with a supported version, we can reopen.