NullPointerException in TopAppBarUiState constructor when accessing recent messages on Android

[ZhyvelM]

Summary

The Intercom Android SDK crashes with a NullPointerException when users tap on "recent messages" or try to access previous chat conversations. The crash occurs in the TopAppBarUiState constructor when it receives a null subtitle parameter.

Environment

SDK Version: intercom_flutter: ^9.4.6
Platform: Android
Flutter Version: 3.6.0+
Target SDK: 34
Min SDK: 24

Steps to Reproduce

Initialize Intercom in the app
Open Intercom messenger (this works fine)
Create message ("test" for example) and go back to main page
Tap on "recent messages" or try to access previous chat conversations
App crashes immediately with the stack trace below

Expected Behavior

Users should be able to access their previous chat conversations and recent messages without the app crashing.

Actual Behavior

App crashes with NullPointerException when trying to load conversation history, specifically when the SDK attempts to create the top app bar state for the conversation view.

Stack Trace

E/AndroidRuntime(27242): FATAL EXCEPTION: main
java.lang.NullPointerException: Parameter specified as non-null is null: method io.intercom.android.sdk.m5.conversation.states.TopAppBarUiState.<init>, parameter subtitle
E/AndroidRuntime(27242): 	at io.intercom.android.sdk.m5.conversation.states.TopAppBarUiState.<init>(Unknown Source:7)
E/AndroidRuntime(27242): 	at io.intercom.android.sdk.m5.conversation.reducers.HeaderReducerKt.reduceTopAppBarUiState(HeaderReducer.kt:45)
E/AndroidRuntime(27242): 	at io.intercom.android.sdk.m5.conversation.reducers.ConversationReducer.computeUiState$intercom_sdk_base_release(ConversationReducer.kt:68)
E/AndroidRuntime(27242): 	at io.intercom.android.sdk.m5.conversation.ConversationViewModel$special$$inlined$map$1$2.emit(Emitters.kt:220)
E/AndroidRuntime(27242): 	at kotlinx.coroutines.flow.StateFlowImpl.collect(StateFlow.kt:392)
E/AndroidRuntime(27242): 	at kotlinx.coroutines.flow.StateFlowImpl$collect$1.invokeSuspend(Unknown Source:15)
E/AndroidRuntime(27242): 	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
E/AndroidRuntime(27242): 	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:104)
E/AndroidRuntime(27242): 	at android.os.Handler.handleCallback(Handler.java:1087)
E/AndroidRuntime(27242): 	at android.os.Handler.dispatchMessage(Handler.java:125)
E/AndroidRuntime(27242): 	at android.os.Looper.dispatchMessage(Looper.java:333)
E/AndroidRuntime(27242): 	at android.os.Looper.loopOnce(Looper.java:263)
E/AndroidRuntime(27242): 	at android.os.Looper.loop(Looper.java:367)
E/AndroidRuntime(27242): 	at android.app.ActivityThread.main(ActivityThread.java:9230)
E/AndroidRuntime(27242): 	at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(27242): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:593)
E/AndroidRuntime(27242): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:929)