Resetting TrackingEventProcessor works differently if event-store is empty

Basic information

• Axon Framework version: 4.4.3 (also tried 4.5)
• JDK version: openjdk version “11.0.3” 2019-04-16 LTS

Steps to reproduce

@RestController
@ProcessingGroup("migrator")
public class Migrator {

    @Autowired
    private EventStorageEngine ese;

    @EventHandler
    public void on(Event e) {
    }

    @Autowired
    private AxonConfiguration configuration;

    @GetMapping("/migrate")
    public void migrate() {
        configuration.eventProcessingConfiguration()
            .eventProcessorByProcessingGroup("migrator", TrackingEventProcessor.class)
            .ifPresent(tep -> {
                tep.shutDown();
            });

        ese.appendEvents(...); // add some 'Event'-events

        configuration.eventProcessingConfiguration()
            .eventProcessorByProcessingGroup("migrator", TrackingEventProcessor.class)
            .ifPresent(tep -> {
                TrackingToken ht = tep.getMessageSource().createHeadToken();
                tep.resetTokens(ht);
                tep.start();
            });
    }

}

I have this RestController in my application. The application starts with an empty database. The idea is to halt processing, insert new events and then resume processing but skipping everything that was just added. It does not work like I expected the first time I run this though. The first time around the EventHandler is called for each of the new events. Subsequent calls to /migrate don’t do this and the events are skipped.

Expected behaviour

EventHandler is never called.

Actual behaviour

EventHandler is called for each event the first time /migrate is called (when Event-Store is empty), but not on subsequent calls.

[smcvb]

I just wanted to let you know @michaelbub that the fix described in pull request #1802 has just been released under 4.5.1. It should be available for download soon!

[smcvb]

Closing this issue as it has been resolved in pull request #1802