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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"MessagingRSocket incorrectly tries to release entire input stream on channel interaction ","articleBody":"The issue was discovered in Spring Security tests after a recent fix in Reactor Core to the `switchOnFirst` operator which now properly detects and flags the scenario.\r\n\r\nIn an RSocket channel interaction, a Spring server responder fails to find a matching route and in that scenarios the exception occurs. The server handles this with `switchOnFirst` and in the end, if input stream wasn't subscribed to (e.g. because there was no matching handler), it subscribes in order to release the payloads resulting in:\r\n\r\n```\r\nreactor.core.Exceptions$ErrorCallbackNotImplemented: java.util.concurrent.CancellationException: FluxSwitchOnFirst has already been cancelled\r\nCaused by: java.util.concurrent.CancellationException: FluxSwitchOnFirst has already been cancelled\r\n\tat reactor.core.publisher.FluxSwitchOnFirst$SwitchOnFirstMain.subscribe(FluxSwitchOnFirst.java:348) ~[reactor-core-3.3.4.BUILD-SNAPSHOT.jar:3.3.4.BUILD-SNAPSHOT]\r\n\tat reactor.core.publisher.Flux.subscribe(Flux.java:8260) ~[reactor-core-3.3.4.BUILD-SNAPSHOT.jar:3.3.4.BUILD-SNAPSHOT]\r\n\tat reactor.core.publisher.Flux.subscribeWith(Flux.java:8424) ~[reactor-core-3.3.4.BUILD-SNAPSHOT.jar:3.3.4.BUILD-SNAPSHOT]\r\n\tat reactor.core.publisher.Flux.subscribe(Flux.java:8231) ~[reactor-core-3.3.4.BUILD-SNAPSHOT.jar:3.3.4.BUILD-SNAPSHOT]\r\n\tat reactor.core.publisher.Flux.subscribe(Flux.java:8158) ~[reactor-core-3.3.4.BUILD-SNAPSHOT.jar:3.3.4.BUILD-SNAPSHOT]\r\n\tat reactor.core.publisher.Flux.subscribe(Flux.java:8101) ~[reactor-core-3.3.4.BUILD-SNAPSHOT.jar:3.3.4.BUILD-SNAPSHOT]\r\n\tat org.springframework.messaging.rsocket.annotation.support.MessagingRSocket.lambda$handleAndReply$5(MessagingRSocket.java:177) ~[spring-messaging-5.2.4.RELEASE.jar:5.2.4.RELEASE]\r\n```\r\n\r\nWe shouldn't subscribe to the entire input which in a channel interaction can be quite long. In any case only the first payload is received at that point, and it's the only one that needs releasing.\r\n","author":{"url":"https://github.com/rstoyanchev","@type":"Person","name":"rstoyanchev"},"datePublished":"2020-03-20T09:55:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/24741/spring-framework/issues/24741"}