Make EnableReactiveMethodSecurity compatible with Kotlin Coroutines

[TonCherAmi]

Current implementation of PrePostAdviceReactiveMethodInterceptor makes it impossible to use @Pre/PostAuthorize with suspending functions:

// PrePostAdviceReactiveMethodInterceptor::invoke
if (!Publisher.class.isAssignableFrom(returnType)) {
    throw new IllegalStateException("The returnType " + returnType + " on " + method + " must return an instance of org.reactivestreams.Publisher (i.e. Mono / Flux) in order to support Reactor Context");
}

This may be related to spring-projects/spring-framework#22462

Spring boot version: 2.2.1.RELEASE

[rwinch]

Could you please provide a complete sample?

[TonCherAmi]

@rwinch here you go.

Upon making a request,

curl -X POST -v -u admin:qwerty localhost:8080/api/test -d "xzcvxzcv"

an exception is thrown:

{
  "timestamp": "2020-03-18T19:57:41.277+0000",
  "path": "/api/test",
  "status": 500,
  "error": "Internal Server Error",
  "message": "The returnType class java.lang.Object on public java.lang.Object com.example.demo.handlers.TestHandler.test(org.springframework.web.reactive.function.server.ServerRequest,kotlin.coroutines.Continuation) must return an instance of org.reactivestreams.Publisher (i.e. Mono / Flux) in order to support Reactor Context",
  "requestId": "38010f7a-4"
}

---

Complete stacktrace:

2020-03-18 23:01:43.416 ERROR 5208 --- [oundedElastic-1] a.w.r.e.AbstractErrorWebExceptionHandler : [c3f2d0af-1]  500 Server Error for HTTP POST "/api/test"

java.lang.IllegalStateException: The returnType class java.lang.Object on public java.lang.Object com.example.demo.handlers.TestHandler.test(org.springframework.web.reactive.function.server.ServerRequest,kotlin.coroutines.Continuation) must return an instance of org.reactivestreams.Publisher (i.e. Mono / Flux) in order to support Reactor Context
	at org.springframework.security.access.prepost.PrePostAdviceReactiveMethodInterceptor.invoke(PrePostAdviceReactiveMethodInterceptor.java:76) ~[spring-security-core-5.3.0.RELEASE.jar:5.3.0.RELEASE]
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	|_ checkpoint ⇢ org.springframework.security.web.server.authorization.AuthorizationWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.authorization.ExceptionTranslationWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.authentication.logout.LogoutWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.savedrequest.ServerRequestCacheWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.context.SecurityContextServerWebExchangeWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.authentication.AuthenticationWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.context.ReactorContextWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.header.HttpHeaderWriterWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.config.web.server.ServerHttpSecurity$ServerWebExchangeReactorContextWebFilter [DefaultWebFilterChain]
	|_ checkpoint ⇢ org.springframework.security.web.server.WebFilterChainProxy [DefaultWebFilterChain]
	|_ checkpoint ⇢ HTTP POST "/api/test" [ExceptionHandlingWebHandler]
Stack trace:
		at org.springframework.security.access.prepost.PrePostAdviceReactiveMethodInterceptor.invoke(PrePostAdviceReactiveMethodInterceptor.java:76) ~[spring-security-core-5.3.0.RELEASE.jar:5.3.0.RELEASE]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.4.RELEASE.jar:5.2.4.RELEASE]
		at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:747) ~[spring-aop-5.2.4.RELEASE.jar:5.2.4.RELEASE]
		at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689) ~[spring-aop-5.2.4.RELEASE.jar:5.2.4.RELEASE]
		at com.example.demo.handlers.TestHandler$$EnhancerBySpringCGLIB$$71f7a9a3.test(<generated>) ~[main/:na]
		at com.example.demo.RoutingConfig$routes$1$1$1.invoke(RoutingConfig.kt:21) ~[main/:na]
		at com.example.demo.RoutingConfig$routes$1$1$1.invoke(RoutingConfig.kt:16) ~[main/:na]
		at org.springframework.web.reactive.function.server.CoRouterFunctionDsl$asHandlerFunction$1$1.invokeSuspend(CoRouterFunctionDsl.kt:599) ~[spring-webflux-5.2.4.RELEASE.jar:5.2.4.RELEASE]
		at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) ~[kotlin-stdlib-1.3.70.jar:1.3.70-release-328 (1.3.70)]
		at kotlinx.coroutines.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:314) ~[kotlinx-coroutines-core-1.3.4.jar:na]
		at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:26) ~[kotlinx-coroutines-core-1.3.4.jar:na]
		at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:109) ~[kotlinx-coroutines-core-1.3.4.jar:na]
		at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:158) ~[kotlinx-coroutines-core-1.3.4.jar:na]
		at kotlinx.coroutines.reactor.MonoKt$monoInternal$1.accept(Mono.kt:55) ~[kotlinx-coroutines-reactor-1.3.4.jar:na]
		at kotlinx.coroutines.reactor.MonoKt$monoInternal$1.accept(Mono.kt) ~[kotlinx-coroutines-reactor-1.3.4.jar:na]
		at reactor.core.publisher.MonoCreate.subscribe(MonoCreate.java:57) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:121) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:203) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:203) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2267) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.request(FluxPeekFuseable.java:137) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.request(FluxPeekFuseable.java:137) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:162) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2075) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:1949) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onSubscribe(FluxMapFuseable.java:90) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onSubscribe(FluxPeekFuseable.java:171) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onSubscribe(FluxPeekFuseable.java:171) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4110) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:211) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:161) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4110) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:141) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilter$FilterSubscriber.onNext(FluxFilter.java:107) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:92) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1705) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:241) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:92) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:121) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:112) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onNext(FluxMapFuseable.java:287) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableConditionalSubscriber.onNext(FluxFilterFuseable.java:330) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1705) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:144) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:112) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2267) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.request(FluxFilterFuseable.java:184) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onSubscribe(MonoFlatMap.java:103) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onSubscribe(FluxFilterFuseable.java:81) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoCurrentContext.subscribe(MonoCurrentContext.java:35) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:121) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:112) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2267) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.request(FluxFilterFuseable.java:184) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:162) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onSubscribe(MonoFlatMap.java:103) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onSubscribe(FluxMapFuseable.java:90) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onSubscribe(FluxFilterFuseable.java:81) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4110) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:211) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:161) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4110) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4110) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilter$FilterSubscriber.onComplete(FluxFilter.java:160) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2269) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2075) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:1949) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4110) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoNext$NextSubscriber.onComplete(MonoNext.java:96) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilter$FilterSubscriber.onComplete(FluxFilter.java:160) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.checkTerminated(FluxFlatMap.java:823) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.drainLoop(FluxFlatMap.java:589) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.drain(FluxFlatMap.java:569) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.onComplete(FluxFlatMap.java:455) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:289) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:225) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.onSubscribe(FluxFlatMap.java:363) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:161) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1705) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onComplete(FluxDefaultIfEmpty.java:100) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:136) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:136) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxFilter$FilterSubscriber.onComplete(FluxFilter.java:160) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxMap$MapConditionalSubscriber.onComplete(FluxMap.java:262) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1706) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoCacheTime$CoordinatorSubscriber.signalCached(MonoCacheTime.java:320) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.MonoCacheTime$CoordinatorSubscriber.onNext(MonoCacheTime.java:337) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:192) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.publisher.FluxSubscribeOnCallable$CallableSubscribeOnSubscription.run(FluxSubscribeOnCallable.java:249) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28) ~[reactor-core-3.3.3.RELEASE.jar:3.3.3.RELEASE]
		at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_232]
		at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) ~[na:1.8.0_232]
		at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) ~[na:1.8.0_232]
		at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_232]
		at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_232]
		at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_232]

[rwinch]

Thanks for the detailed sample. I don't think this can work at the moment because the ReactiveSecurityContextHolder leverages Reactor's Context which as far as I know requires the return types to be Mono or Flux at this point. Any method that breaks this chain would mean we would not have access to the Authentication and cannot perform any security checks.

@simonbasle Can you comment if Reactor's Context works with (or could work with) Kotlin Coroutines?

[simonbasle]

IIRC Kotlin Coroutines' have their own concept of context which can be bridged over to Reactor's Context when adapting a Flux/Mono (and should be when using the official bridges IIRC, if that is still a thing). maybe @sdeleuze will have more insight into that.

[TonCherAmi]

Interop between coroutine context and Reactor context should be possible according to this issue Kotlin/kotlinx.coroutines#284

[rwinch]

Thanks for the additional details @simonbasle and @TonCherAmi We will look into this one once spring-projects/spring-framework#22462 is addressed.