[Bug]: NullReferenceException : Object reference not set to an instance of an object - GetTags

[RaphaelNSG]

What happened?

I updated my project to OneSignal 3.0 and everything was working fine, but some users are reporting an error. It seems related with GetTags method, but i don't know what is causing this error.

Steps to reproduce?

1. Install the OneSignal 3.0
2. Call the `GetTags` method

What did you expect to happen?

I expected to call the GetTags method and receive no error.

Unity version

2019.4.35f1

OneSignal Unity SDK version

3.0.0

Platform

Android and IOS

Relevant log output

Non-fatal Exception: java.lang.Exception: NullReferenceException : Object reference not set to an instance of an object.
       at OneSignalService+<SendIncrementalData>d__0.MoveNext(OneSignalService+<SendIncrementalData>d__0)
       at System.Threading.ContextCallback.Invoke(System.Threading.ContextCallback)
       at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext)
       at System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner.Run(System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner)
       at System.Action.Invoke(System.Action)
       at System.Threading.ContextCallback.Invoke(System.Threading.ContextCallback)
       at System.Threading.Tasks.AwaitTaskContinuation.RunCallback(System.Threading.Tasks.AwaitTaskContinuation)
       at System.Threading.Tasks.Task.FinishContinuations(System.Threading.Tasks.Task)
       at System.Threading.Tasks.Task`1[TResult].TrySetResult(System.Threading.Tasks.Task`1[TResult])
       at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].SetResult(System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult])
       at OneSignalSDK.OneSignalAndroid+<GetTags>d__96.MoveNext(OneSignalSDK.OneSignalAndroid+<GetTags>d__96)
       at System.Threading.ContextCallback.Invoke(System.Threading.ContextCallback)
       at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext)
       at System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner.Run(System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner)
       at System.Action.Invoke(System.Action)
       at System.Threading.ContextCallback.Invoke(System.Threading.ContextCallback)
       at System.Threading.Tasks.AwaitTaskContinuation.RunCallback(System.Threading.Tasks.AwaitTaskContinuation)
       at System.Threading.Tasks.Task.FinishContinuations(System.Threading.Tasks.Task)
       at System.Threading.Tasks.Task`1[TResult].TrySetResult(System.Threading.Tasks.Task`1[TResult])
       at System.Threading.Tasks.TaskCompletionSource`1[TResult].TrySetResult(System.Threading.Tasks.TaskCompletionSource`1[TResult])
       at Laters.AwaitableAndroidJavaProxy`1[TResult]._setResult(Laters.AwaitableAndroidJavaProxy`1[TResult])
       at System.Action`1[T].Invoke(System.Action`1[T])
       at System.Threading.SendOrPostCallback.Invoke(System.Threading.SendOrPostCallback)
       at UnityEngine.UnitySynchronizationContext+WorkRequest.Invoke(UnityEngine.UnitySynchronizationContext+WorkRequest)
       at UnityEngine.UnitySynchronizationContext.Exec(UnityEngine.UnitySynchronizationContext)
       at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(System.Runtime.ExceptionServices.ExceptionDispatchInfo)
       at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0(System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c)
       at System.Threading.SendOrPostCallback.Invoke(System.Threading.SendOrPostCallback)
       at UnityEngine.UnitySynchronizationContext+WorkRequest.Invoke(UnityEngine.UnitySynchronizationContext+WorkRequest)
       at UnityEngine.UnitySynchronizationContext.Exec(UnityEngine.UnitySynchronizationContext)
       at UnityEngine.UnitySynchronizationContext:Exec(UnityEngine)

Code of Conduct

• [X] I agree to follow this project's Code of Conduct

[adamschlesinger]

Hey @RaphaelNSG can you tell me more about the device you tested this on? The device model and which version of Android you used would be great.

[RaphaelNSG]

Hey @adamschlesinger sorry for the delay. Actually this error is happening on Android and IOS in many devices. For exemple:

• Iphone XR = 15.4.1
• Iphone 6 = 12.5.5-
• Xiaomi MI 8 Lite = Android 10
• Samsung Galaxy A30 = Android 11

[RaphaelNSG]

IOS error:

Non-fatal Exception: NullReferenceException
0  ???                            0x0 MoveNext (OneSignalService+<SendIncrementalData>d__0)
1  ???                            0x0 Invoke (System.Threading.ContextCallback)
2  ???                            0x0 RunInternal (System.Threading.ExecutionContext)
3  ???                            0x0 Run (System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner)
4  ???                            0x0 Invoke (System.Action)
5  ???                            0x0 Invoke (System.Threading.ContextCallback)
6  ???                            0x0 RunCallback (System.Threading.Tasks.AwaitTaskContinuation)
7  ???                            0x0 FinishContinuations (System.Threading.Tasks.Task)
8  ???                            0x0 TrySetResult (System.Threading.Tasks.Task`1[TResult])
9  ???                            0x0 SetResult (System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult])
10 ???                            0x0 MoveNext (OneSignalSDK.OneSignalIOS+<GetTags>d__139)
11 ???                            0x0 Invoke (System.Threading.ContextCallback)
12 ???                            0x0 RunInternal (System.Threading.ExecutionContext)
13 ???                            0x0 Run (System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner)
14 ???                            0x0 Invoke (System.Action)
15 ???                            0x0 Invoke (System.Threading.SendOrPostCallback)
16 ???                            0x0 Invoke (UnityEngine.UnitySynchronizationContext+WorkRequest)
17 ???                            0x0 Exec (UnityEngine.UnitySynchronizationContext)
18 ???                            0x0 Throw (System.Runtime.ExceptionServices.ExceptionDispatchInfo)
19 ???                            0x0 <ThrowAsync>b__6_0 (System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c)
20 ???                            0x0 Invoke (System.Threading.SendOrPostCallback)
21 ???                            0x0 Invoke (UnityEngine.UnitySynchronizationContext+WorkRequest)
22 ???                            0x0 Exec (UnityEngine.UnitySynchronizationContext)
23 ???                            0x0 UnitySynchronizationContext:Exec (UnityEngine)

[jkasten2]

@RaphaelNSG Thanks for the stacktrace, however it doesn't provide any extra details to investigate. Could you share where and how you are calling GetTags? Could you share some of your code?

We have a new 3.0.1 version, could you also tell us if the issue happens there as well?

[RaphaelNSG]

@jkasten2 I figure out that the GetTags() function is returning 'null' and that is what is causing the NullReferenceException. This is my function:

public static async void SendIncrementalData(string key)
    {
        Dictionary<string, object> tags = await OneSignal.Default.GetTags();

        if (tags.ContainsKey(key))
        {
            int value = int.Parse(tags[key].ToString());
            value++;
            OneSignal.Default.SendTag(key, value.ToString());
        }
        else
        {
            OneSignal.Default.SendTag(key, "1");
        }
    }

Can the result of GetTags function be null?

[adamschlesinger]

Hi @RaphaelNSG yes the object returned by GetTags can be null.

[RaphaelNSG]

@adamschlesinger thanks for the answer, but this is new because in the older version this never happened, so it might be a good idea to update the documentation with this information.

[adamschlesinger]

@RaphaelNSG definitely! We're also going to evaluate if this is ideal behavior or not.