Receiving `ConcurrentModificationExceptionThrown` when `registerSuperPropertiesMap` or `track` is called from `onResume`

[hakanbagci]

Here is the related part from stack trace for this exception. It seems like superPropertiesCache map is somehow concurrently being modified.

java.util.LinkedHashMap$LinkedHashIterator.nextEntry (LinkedHashMap.java:346) java.util.LinkedHashMap$EntryIterator.next (LinkedHashMap.java:375) java.util.LinkedHashMap$EntryIterator.next (LinkedHashMap.java:373) org.json.JSONObject.writeTo (JSONObject.java:719) org.json.JSONStringer.value (JSONStringer.java:237) org.json.JSONObject.writeTo (JSONObject.java:720) org.json.JSONObject.toString (JSONObject.java:689) com.mixpanel.android.mpmetrics.PersistentIdentity.storeSuperProperties (PersistentIdentity.java:556) com.mixpanel.android.mpmetrics.PersistentIdentity.registerSuperProperties (PersistentIdentity.java:244) com.mixpanel.android.mpmetrics.MixpanelAPI.registerSuperProperties (MixpanelAPI.java:759) com.mixpanel.android.mpmetrics.MixpanelAPI.registerSuperPropertiesMap (MixpanelAPI.java:733) de.flixbus.analytics.mixpanel.MixpanelGuard.registerSuperProperties (MixpanelGuard.java:28)

This is not happening all the time, but happening quite often. It is also not specific to a device family or to an android version.

[hakanbagci]

Hey Mixpanel team, did you have time to check this bug?

[hakanbagci]

Some additional context: It is only happening if track or registerSuperProperties methods of MixpanelAPI are called from onResume callback method of the first activity.

[patedit]

thanks for your patience @hakanbagci. We haven't been able to reproduce this issue (and we've tried hard). Even so, we added a lock when accessing super properties which will, hopefully, solve your crash. Feel free to take a look at the PR #676