java.lang.ArrayIndexOutOfBoundsException when syncing data

[ewa-radomska-codeclusive]

Description

Sometimes during syncing models we see this error:

java.lang.ArrayIndexOutOfBoundsException: length=49; index=49 at java.util.ArrayList.add(ArrayList.java:468) at com.amazonaws.amplify.amplify_datastore.DataStoreHubEventStreamHandler.getHubListener$lambda-0(Unknown Source:12) at com.amazonaws.amplify.amplify_datastore.DataStoreHubEventStreamHandler.a(Unknown Source:0) at d.b.a.e.s0.onEvent(Unknown Source:2) at com.amplifyframework.hub.AWSHubPlugin.a(Unknown Source:4) at d.c.g.b.run(Unknown Source:4) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1137) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:637) at java.lang.Thread.run(Thread.java:1012)

It shows in both headless and foreground mode. It doesn't affect app working, but seems sometimes adding hub event to event history fails.

Categories

• Analytics
• API (REST)
• API (GraphQL)
• Auth
• Authenticator
• DataStore
• Notifications (Push)
• Storage

Steps to Reproduce

Hard to reproduce it in the app with particular steps. One of our team's member found this when add object and than immediately edit it (but it's not showing all the time in this particular case). We see a lot of this bugs in production and everytime it shows during sync when a lot of models are syncing like in those logs:

[Headless HubListener] networks active : true
13:04:17
[Headless HubListener] sync on models : [Yepic, Image, ImageNote, Task, TaskNote, Stop, YepicVisit, OpenVisit, Note, YepicPlace, VisitNote]
13:04:17
[Headless HubListener] sync on model : Yepic  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:20
[Headless HubListener] sync on model : Image  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:20
[Headless HubListener] sync on model : ImageNote  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:20
[Headless HubListener] sync on model : Task  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:20
[Headless HubListener] sync on model : TaskNote  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:23
[Headless HubListener] sync on model : Stop  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:24
[Headless HubListener] sync on model : YepicVisit  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false
13:04:24
[Headless HubListener] YepicVisit model synced - turning observer on
13:04:24
CRASH
java.lang.ArrayIndexOutOfBoundsException: length=73; index=73
MAPPINGS
Missing 
STATUS

Open
Received:2023-05-24 13:04:24
java.lang.ArrayIndexOutOfBoundsException: length=73; index=73
	at java.util.ArrayList.add(ArrayList.java:468)
	at com.amazonaws.amplify.amplify_datastore.DataStoreHubEventStreamHandler.getHubListener$lambda-0(Unknown Source:12)
	at com.amazonaws.amplify.amplify_datastore.DataStoreHubEventStreamHandler.a(Unknown Source:0)
	at d.b.a.e.s0.onEvent(Unknown Source:2)
	at com.amplifyframework.hub.AWSHubPlugin.a(Unknown Source:4)
	at d.c.g.b.run(Unknown Source:4)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1137)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:637)
	at java.lang.Thread.run(Thread.java:1012)
Expand
13:04:24
[Headless HubListener] sync on model : OpenVisit  , added : 0, deleted : 0, updated : 0, delta sync : true, full sync : false

looks like everytime the problem is connected with adding new event to event history. We are trying to figure out if the problem is on our code side or on Amplify Flutter side and if we are doing something wrong what it can be. Any suggestions will be very helpful

Screenshots

No response

Platforms

• iOS
• Android
• Web
• macOS
• Windows
• Linux

Flutter Version

3.10.4

Amplify Flutter Version

1.1.0

Deployment Method

Amplify CLI

Schema

No response

[stevegaunt]

@HuiSF

As an observation

Looking at the stacktrace,
An index out of bounds within the add method will be likely to add something to an Array with an index that was too big. The ArrayList stores its data in an Array and maintains the size of that Array automatically. If 2 threads call add at the same time the check for capacity can pass, with only one thread successfully adding, then the other thread will throw the java.lang.ArrayIndexOutOfBoundsException.

This indicates there is a multithread issue when amplify is playing the events…

[HuiSF]

Hi @stevegaunt thanks for the diagnose, we will look into this issue.

[stevegaunt]

@HuiSF @NikaHsn
any updates with this?? It's effecting live users for us

[NikaHsn]

@stevegaunt I don't have an update yet. I'll see how we can prioritize this and will update here on progress. thanks for your patience.

[BrandowBuenos]

Same here!

[NikaHsn]

This has been fixed in v1.3.1. Thanks for your patience resolving this issue.