RejectedExecutionException: Task rejected from ScheduledThreadPoolExecutor

[dpgmedia-gdebrucker]

Describe the bug
In Crashlytics we see 109 crashes during the initialisation of Snowplow. The stack trace is always the same, the "pool size" and "completed tasks" vary.

The completed tasks can go up to 23, which I do not understand. Snowplow is one of the very first things we initialise after fetching a remote config at app startup. This initialisation happens through a single instance, so there shouldn't have been any other Snowplow interactions.

Fatal Exception: java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@7738e11[Not completed] rejected from java.util.concurrent.ScheduledThreadPoolExecutor@3a2db76[Shutting down, pool size = 5, active threads = 1, queued tasks = 0, completed tasks = 4]
       at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2082)
       at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:842)
       at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:345)
       at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:586)
       at java.util.concurrent.ScheduledThreadPoolExecutor.submit(ScheduledThreadPoolExecutor.java:738)
       at com.snowplowanalytics.core.emitter.Executor.futureCallable(Executor.kt:129)
       at com.snowplowanalytics.core.emitter.storage.SQLiteEventStore.<init>(SQLiteEventStore.kt:71)
       at com.snowplowanalytics.core.emitter.Emitter.getEventStore(Emitter.kt:95)
       at com.snowplowanalytics.core.emitter.Emitter.<init>(Emitter.kt:95)
       at com.snowplowanalytics.core.tracker.ServiceProvider.makeEmitter(ServiceProvider.kt:251)
       at com.snowplowanalytics.core.tracker.ServiceProvider.getOrMakeEmitter(ServiceProvider.kt:185)
       at com.snowplowanalytics.core.tracker.ServiceProvider.makeTracker(ServiceProvider.kt:265)
       at com.snowplowanalytics.core.tracker.ServiceProvider.getOrMakeTracker(ServiceProvider.kt:189)
       at com.snowplowanalytics.core.tracker.ServiceProvider.<init>(ServiceProvider.kt:87)
       at com.snowplowanalytics.snowplow.Snowplow.createTracker(Snowplow.kt:275)
       at <<our-package-name>>.snowplow.SnowplowInitializer.init(SnowplowInitializer.kt:70)
       at <<our-package-name>>.Tracking.<init>(Tracking.kt:51)
       at <<our-package-name>>.Tracking.<init>(Tracking.kt:15)
       at <<our-package-name>>.Tracking.<init>(Tracking.kt:15)
       at <<our-package-name>>.Tracking$Factory.create(Tracking.kt:34)
       at <<our-package-name>>.config.InitConfigHandler$tracking$2.invoke(InitConfigHandler.kt:78)
       at <<our-package-name>>.config.InitConfigHandler$tracking$2.invoke(InitConfigHandler.kt:77)
       at kotlin.SynchronizedLazyImpl.getValue(LazyJVM.kt:74)
       at <<our-package-name>>.config.InitConfigHandler.getTracking$tracking_release(InitConfigHandler.kt:77)
       at <<our-package-name>>.config.InitConfigHandler$1$callback$1$1.invokeSuspend(InitConfigHandler.kt:100)
       at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
       at kotlinx.coroutines.CoroutineContextKt.withContinuationContext(CoroutineContext.kt:104)
       at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:86)
       at kotlinx.coroutines.internal.LimitedDispatcher$Worker.run(LimitedDispatcher.kt:111)
       at kotlinx.coroutines.scheduling.TaskImpl.run(Tasks.kt:99)
       at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:584)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:811)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:715)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:702)

To Reproduce
We are not able to reproduce this, this is happening rarely in our production environment.

Expected behavior
If the Snowplow is unable create to initialise is should retry or fail gracefully. Not crash the app.

Screenshots

Device informatoin (please complete the following information):
68% Samsung

• 6% Galaxy A52s 5G
• 6% Galaxy A52
• 5% Galaxy S20 FE 5G
• 51% Other (34)
  7% Oneplus
  6% TCT Mobile Limited (Alcatel)
  5% Xiaomi
  14% Other (6)

[matus-tomlein]

Thank you for reporting this @dpgmedia-gdebrucker! We will investigate how to handle the error gracefully.