ReactiveMongoOperationsSessionRepository deleteById throws java.lang.NullPointerException when session is not found

[cmario]

Hi,

I am using spring-session-data-mongodb 2.1.3.RELEASE with spring boot 2.1.5.RELEASE and jdk 11 and I am facing an issue if I have a valid session cookie and for any reason the related session is missing in MongoDB. The deleteById method throws the exception below:

java.lang.NullPointerException: null
	at org.springframework.session.events.AbstractSessionEvent.<init>(AbstractSessionEvent.java:40) ~[spring-session-core-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.springframework.session.events.SessionDestroyedEvent.<init>(SessionDestroyedEvent.java:36) ~[spring-session-core-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.springframework.session.events.SessionDeletedEvent.<init>(SessionDeletedEvent.java:39) ~[spring-session-core-2.1.6.RELEASE.jar:2.1.6.RELEASE]
	at org.springframework.session.data.mongo.ReactiveMongoOperationsSessionRepository.lambda$deleteById$6(ReactiveMongoOperationsSessionRepository.java:142) ~[spring-session-data-mongodb-2.1.3.RELEASE.jar:na]

Looking at the code I think there is a mistake in using "doOnSuccess":

/**
 * Deletes the {@link MongoSession} with the given {@link MongoSession#getId()} or does nothing if the
 * {@link MongoSession} is not found.
 *
 * @param id the {@link MongoSession#getId()} to delete
 */
@Override
public Mono<Void> deleteById(String id) {

	return findSession(id)
			.flatMap(document -> this.mongoOperations.remove(document, this.collectionName).then(Mono.just(document)))
			.map(document -> convertToSession(this.mongoSessionConverter, document))
			.doOnSuccess(mongoSession -> publishEvent(new SessionDeletedEvent(this, mongoSession))) //
			.then();
}

"doOnSuccess" is called even if findSession completes without data, that means mongoSession is null. "doOnNext" should be used instead.

Regards
Mario

[cmario]

Hi there,

is there any chance to have a comment on this?

Thank you
Regards
Mario