Component throws unhandled exceptions and crashes after drag over not expanded lazy-loaded node.

[megaboich]

It seems that lazy-loading is still an experimental issue, so I have created PR to include an example.

Steps to reproduce the actual bug:

1. Go to storybook samples and navigate to Advanced -> Expand with lazy loading of child nodes.
2. Open Console in web browser to see logs.
3. Try to drag Egg node over Spaceship node.
4. Unhandled exceptions are logged.
5. If you drag Egg node from top direction over center of Spaceship node there are even more fatal react exceptions and tree disappears. Please check the recording:
6. Note: fatal errors occurs and tree disappears only on 16 version of React, on 15 it was working quite stable.

This bug documents the problem referenced in issue 211.

As for now I do not have any better ideas other than to recreate my old abandoned PR.

Do you have any ideas how to fix this in most correct way?

[wuweiweiwu]

I'll have to take some time to investigate this issue. However, do you mind creating a codesandbox.io to duplicate this?

FWIW lazy loading isnt a fully tested/supported feature.

Thanks!

[megaboich]

Hi @wuweiweiwu,
Yes, I understand that lazy-loading is not completed feature, also it contradicts a bit with main concept of dnd live-preview (should we load lazy children during dnd?).

I have created codesandbox for this bug: https://codesandbox.io/s/rjxr57ry9p

Also I think that our users don't like automatical expand during DND anyway as described in this issue: #173

I think I will try to implement option to disable auto-expand during DND, and that should solve majority of problems with lazy-loading as well.

What do you think?

[wuweiweiwu]

@megaboich haha yeah umm... I'll have to give that some thought. Yep its added to the umbrella #281.

That'll be awesome! I'll probably get started on a rewrite of the DND implementation soon as well.