Fix issue with over being null in onDragEnd

[adrianmxb]

I am currently implementing drag and drop behavior within our application and I've noticed that sometimes the over property is set to null. Found a issue for this one as well: #391

After some investigation, I was able to reproduce this on storybook in the MultipleContainers example as well, as I first thought I made a mistake in the implementation. Its very hard to reliably reproduce it so pardon me for not providing a codesandbox. I tried writing a test for this but it turns out this is not very easy to achieve.

Ways on how to reproduce (takes quite some time):

1. Do a very fast click (mouse down, mouse up) on a Draggable.
2. The over property you get through onDragEnd is sometimes null.

It really feels like a timing issue, since the sensorContext.over is set through this useIsomorphicLayoutEffect:

dnd-kit/packages/core/src/components/DndContext/DndContext.tsx

Lines 579 to 613 in 5c58f0f

	useIsomorphicLayoutEffect(() => {
	sensorContext.current = {
	activatorEvent,
	active,
	activeNode,
	collisionRect,
	collisions,
	droppableRects,
	draggableNodes,
	draggingNode,
	draggingNodeRect,
	droppableContainers,
	over,
	scrollableAncestors,
	scrollAdjustedTranslate,
	};
	activeRects.current = {
	initial: draggingNodeRect,
	translated: collisionRect,
	};
	}, [
	active,
	activeNode,
	collisions,
	collisionRect,
	draggableNodes,
	draggingNode,
	draggingNodeRect,
	droppableRects,
	droppableContainers,
	over,
	scrollableAncestors,
	scrollAdjustedTranslate,
	]);

By setting over directly in the sensorContext instead of relying on the useIsomorphicLayoutEffect to fire before the onDragEnd callback is called.

[changeset-bot]

🦋 Changeset detected

Latest commit: ef41376

The changes in this PR will be included in the next version bump.

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Name	Type
@dnd-kit/core	Patch

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[balexand]

I'm also having problems with over being null in onDragEnd due to an inconsistently reproducible timing issue. This pull-request does not fix the issue and doesn't seem like the correct approach.