Crash in OrmaListAdapter and OrmaRecyclerViewAdapter on multiple deletions simultaneously

[gfx]

No description provided.

[gfx]

ANR is no longer produced in v0.31.0, but NoValueException may occur in the same situation.

[karino2]

I found similar issue when delete one item (OrmaAdapter sometime cause crash).
Is this the same issue?
My Orma version is 4.2.5.

Note: My issue is hard to reproduce and only happens occasionally. That's why investigation like stabilize reproduce step is difficult.

Here is my stacktrace:

FATAL EXCEPTION: main
Process: karino2.livejournal.com.meatpieday, PID: 11093
com.github.gfx.android.orma.exception.NoValueException: ouf of range: getItem(13) for the relation with 13 items
at com.github.gfx.android.orma.widget.OrmaAdapter.getItem(OrmaAdapter.java:115)
at karino2.livejournal.com.meatpieday.CellListAdapter.getItemId(CellListAdapter.java:35)
at android.widget.AbsListView$RecycleBin.retrieveFromScrap(AbsListView.java:9158)
at android.widget.AbsListView$RecycleBin.getScrapView(AbsListView.java:8886)
at android.widget.AbsListView.obtainView(AbsListView.java:2933)
at android.widget.ListView.makeAndAddView(ListView.java:1945)
at android.widget.ListView.fillDown(ListView.java:719)
at android.widget.ListView.fillSpecific(ListView.java:1391)
at android.widget.ListView.layoutChildren(ListView.java:1712)
at android.widget.AbsListView.onLayout(AbsListView.java:2731)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1080)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:344)
at android.widget.FrameLayout.onLayout(FrameLayout.java:281)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:437)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:344)
at android.widget.FrameLayout.onLayout(FrameLayout.java:281)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1742)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:344)
at android.widget.FrameLayout.onLayout(FrameLayout.java:281)
at com.android.internal.policy.PhoneWindow$DecorView.onLayout(PhoneWindow.java:3146)
at android.view.View.layout(View.java:17993)
at android.view.ViewGroup.layout(ViewGroup.java:5817)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2755)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2456)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1524)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7520)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911)
at android.view.Choreographer.doCallbacks(Choreographer.java:686)
at android.view.Choreographer.doFrame(Choreographer.java:622)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:7325)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1321)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1211)

[karino2]

In normal case, queryObservableSubscription seems called and cache.evictAll() is called.
Is mItemCount of ListView stale?

[karino2]

mItemCount should be updated at AdapterDataSetObserver::onChanged().
This is registered at AbsListView and onChanged is called when BaseAdapter::notifyDataSetChanged() is called.
So, it must be updated if OrmaListAdapter::notifyDatasetChanged() called correctly.

Is there some situation following observer is called before OrmaListAdapter::getCount() is not updated?

        delegate.addSubscription(delegate.getQueryObservable()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Consumer<Selector<Model, ?>>() {
                    @Override
                    public void accept(Selector<Model, ?> selector) throws Exception {
                        notifyDataSetChanged();
                    }
                }));

[karino2]

I guess when cell deleter is called, this subscription is not fired just at time and some UI related preemptin occur for fling case.
I guess Delete and notifyDataSetChanged must be atomic.

Add: But notifyDataSetChanged must be called from UI Thread. How to make sure other fling related operation occure before this action?

[karino2]

This crash occur when there is a race condition for UI update and cursor deletion.
For example, if user select list item via ContextualActionBar, then choose delete.

`
Completable.fromAction(()-> {
getOrmaDatabase()
.deleteFromCell()
.idIn(ids)
.execute();
}).subscribeOn(Schedulers.io())
.subscribe();

actionMode.finish();
`

In this case, CAB related update occur just the same timing as deletion.
If CAB update cause getItem query before notifyDataSetChanged, but cursor is already updated, this cause crash (out of range access).

Work around is CAB finish call before cursor deletion.
This fix most of the case, but not perfect solution for this.
I don't know how to fix this problem.

Cursor have some observer API for data set(registerDataSetObserver).
CursorAdapter register DataSetObserver to cursor, and call notifyDataSetChanged from this observer.
I'm not fully sure whether this code really fix all the race condition, but I guess orma should handle datasetobserver of cursor someway.