encountering an odd error trying out porting an existing wor

Question

encountering an odd error trying out porting an existing working application <http 1 6 to|1 6 8 to> ktor 2 0 1

Peter · Answer

```java lang UnsupportedOperationException This class is an internal synthetic class generated by the Kotlin compiler such as an anonymous class for a lambda a SAM wrapper a callable reference etc It s not a Kotlin class or interface so the reflection library has no idea what declarations it has Please use Java reflection to inspect this class class com xxx SessionManagementKt$swapUserSession$1$1 at kotlin reflect jvm internal KClassImpl reportUnresolvedClass KClassImpl kt 316 at kotlin reflect jvm internal KClassImpl access$reportUnresolvedClass KClassImpl kt 44 at kotlin jvm internal CallableReference getTypeParameters CallableReference java 156 at kotlin reflect jvm internal ReflectionFactoryImpl typeParameter ReflectionFactoryImpl java 134 at kotlin jvm internal Reflection typeParameter Reflection java 174 at com xxx SessionManagement$swapUserSession$1$1 invokeSuspend SessionManagement kt 162 at kotlin coroutines jvm internal BaseContinuationImpl resumeWith ContinuationImpl kt 33 at arrow continuations generic SuspendMonadContinuation resumeWith SuspendingComputation kt 54 at kotlin coroutines jvm internal BaseContinuationImpl resumeWith ContinuationImpl kt 46 at kotlinx coroutines DispatchedTask run DispatchedTask kt 106 at io netty util concurrent AbstractEventExecutor safeExecute AbstractEventExecutor java 164 at io netty util concurrent SingleThreadEventExecutor runAllTasks SingleThreadEventExecutor java 469 at io netty channel nio NioEventLoop run NioEventLoop java 503 at io netty util concurrent SingleThreadEventExecutor$4 run SingleThreadEventExecutor java 986 at io netty util internal ThreadExecutorMap$2 run ThreadExecutorMap java 74 at io ktor server netty EventLoopGroupProxy$Companion create$lambda 1$lambda 0 NettyApplicationEngine kt 260 ```

Peter · Answer

it appears to be happening inside a route ```fun lt A B C gt Route swapUserSession authenticate auth basic post internal session doThing suspend fun lt A B C gt doThing Bla lt A gt ```

Peter · Answer

using kotlin 1 6 21

Peter · Answer

the suspend fun is a top level function and has generic parameters so does the function that creates the route

Peter · Answer

i m not sure why reflection is now involved here

Peter · Answer

the invocation to `doThing ` actually succeeds and returns a value

Peter · Answer

< Aleksei Tirman JB > any idea by any chance

Aleksei Tirman [JB] · Answer

Sorry for the long delay with a replay Unfortunately I cannot reproduce it with the following code ```fun main embeddedServer Netty port = 3333 install Authentication basic auth basic validate UserIdPrincipal 123 routing swapUserSession lt Int Int Int gt start wait = true fun lt A B C gt Route swapUserSession authenticate auth basic post doThing lt A B C gt suspend fun lt A B C gt doThing Bla lt A gt return Bla lt Int gt as Bla lt A gt class Bla lt T gt ```