Hi, I have been struggling with this for some time and finally decided to post there to make sure it is not me doing something wrong.

Please see attached POC, screen recording and sample crash log in the attached file. Project is created with Android Studio Koala Feature Drop | 2024.1.2 Canary 5

Issue:

Attached project demonstrates crash with a Room database but I use custom PagingSource because I also use Paging 3 with content providers such as call log and contacts.

Due to my my project's needs, I need to invalidate PagingSource from outside every now and then. One of the reasons for that is inserting adverts to certain locations.

I created Invalidator interface which InvalidatingPagingSource that extends PagingSource uses. InvalidatingPagingSource in return extended by my custom paging source and ViewModel is provided with an instance of Invalidator so it can call Invalidator.invalidateNow() when it needs to invalidate the paging source.

This setup works fine when data is on screen and no scrolling is being done. However, if invalidation happens while user is scrolling app crashes with

java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position 115(offset:115).state:207 androidx.recyclerview.widget.RecyclerView{fdd315c VFED.V... ......ID 48,48-1296,2800 #7f080143 app:id/notesRecycler}, adapter:com.example.paging3.NotesAdapterPaging@52fd8c2, layout:androidx.recyclerview.widget.LinearLayoutManager@17696d3, context:com.example.paging3.MainActivity@1d73791
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6364)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6300)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6296)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2330)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1631)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1591)
at androidx.recyclerview.widget.LinearLayoutManager.scrollBy(LinearLayoutManager.java:1395)
at androidx.recyclerview.widget.LinearLayoutManager.scrollVerticallyBy(LinearLayoutManager.java:1136)
at androidx.recyclerview.widget.RecyclerView.scrollStep(RecyclerView.java:1972)
at androidx.recyclerview.widget.RecyclerView$ViewFlinger.run(RecyclerView.java:5476)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1339)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1348)
at android.view.Choreographer.doCallbacks(Choreographer.java:952)
at android.view.Choreographer.doFrame(Choreographer.java:878)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1322)
at android.os.Handler.handleCallback(Handler.java:958)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:205)
at android.os.Looper.loop(Looper.java:294)
at android.app.ActivityThread.main(ActivityThread.java:8177)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

I am not sure if I am being thick but, when I check the source of tryGetViewHolderForPositionByDeadline I see that it does these checks:

if (position < 0 || position >= mState.getItemCount()) {    
throw new IndexOutOfBoundsException("Invalid item position " + position    
+ "(" + position + "). Item count:" + mState.getItemCount()
+ exceptionLabel()); 
}

According to log however, position 115(offset:115) falls in to state:207 so crash should not happen. What am I missing?

Notes:

Please be patient after first lunch as app creates 5K sample notes.
You may need to scroll fast a couple of times to create the crash.