Ckeditor5: Editor crashes after undoing changes related to block quotes in nested list

[Mgsy]

Steps to reproduce

1. Go to https://ckeditor5.github.io/ and don't delete editor's content.
2. Create an ordered list and type some text.
3. Press enter, type some text and press TAB to create a nested list.
4. Repeat step 3 10 times without pressing TAB (you should have 10 nested items).
5. Transform nested items number 10 (last one), 1 (first one) and 5 (middle one) into quote block.
6. Press CTRL + Z 3 times to undo changes.
7. Put a cursor on nested item 6.
8. Click on a block quote button twice (to transform it into quote block and undo changes. Important: Don't use CTRL + Z).
9. Press CTRL + Z.

Current result

• After doing step 8, list item is removed.
• After doing step 9, editor crashes.

Logs

Logs from console - https://gist.github.com/Mgsy/82513d50078417e601146d0813ffc430

Notes

This bug could be pretty hard to reproduce, so feel free to comment if you have problem with it.

Other informations

OS: Windows 10, Ubuntu 16.04
Release: 0.10.0

[Reinmar]

May be related to https://github.com/ckeditor/ckeditor5/issues/445.

[Reinmar]

There are different issues now. E.g., the previously nested list items are not nested anymore after undo.

So, we can't work on this bug anyway for now.

[Reinmar]

I'm not sure why I actually added this issue to any iteration. It's very hard to reproduce. Perhaps there weren't more important issues back then :D Let's reprioritise now.

[Mgsy]

This bug isn't reproducible anymore. https://github.com/ckeditor/ckeditor5/issues/446#issuecomment-315124528 was fixed as well.