[bug] Sortable.get(event.target).sort not working as expected

[FFdhorkin]

Describe the bug I have a series of rows, each of which has a label that shows its current index.

Without an onChange handler, the controls reorder properly, but the index label is not updating.

With my onChange handler, nothing happens visually when I drag item # 3 over # 2 (though I can see a console.log showing the correct oldIndex and newIndex). When I drag item # 3 over item # 1, suddenly the index labels /controls fluctuate rapidly. It looks like item # 1 and # 3 are swapping positions repeatedly.

I originally tried to use setState in the onChange handler, but that seemed to lead to duplicate controls for some reason. (There were also errors about q.parentNode is null when I tried setState)

To Reproduce Steps to reproduce the behavior:

1. In child object, have an index in props that is used for displaying row #

2. add onChange handler to container:

   onChange={(event, sortable) => {
   event.stopPropagation();
   const { oldIndex, newIndex } = event;
   const order = sortable!.toArray();
   
   console.log(`${oldIndex}, ${newIndex}`);
   console.log(JSON.stringify(order));
   order.splice(newIndex!, 0, order.splice(oldIndex!, 1)[0]);
   console.log(JSON.stringify(order));
   Sortable.get(event.target)?.sort(order, true);
   }}

   Expected behavior

   • If you drag item # 3 over # 2, then the displayed order should be what was originally 1/3/2.
   • If you drag item # 3 over # 1, then the displayed order should be 3/1/2.

Actual behavior

• If you drag item # 3 over # 2, nothing happens if there's an onChange. (Without onChange, it works, but index label isn't updating)
• If you drag item # 3 over # 1, items # 1 and # 3 seem to swap rapidly

Information Versions react-sortable = ^6.1.4 react = ^18.2.0

Before drag: Dragging # 3 over # 2: Dragging # 3 over # 1 fluctuates between these states:

As a reference, here's what happens when I drag # 3 over # 2 if there's no onChange:

And here's what happens if I try to use this.setState to update order: