Pasting empty nested list and converting it to different list type throws error

[jswiderski]

Type of report

Bug

Provide detailed reproduction steps (if any)

1. Go to https://sdk.ckeditor.com/samples/fullpreset.html.
2. Clear Editor contents and switch to source mode.
3. Paste below HTML

<ul>	
	<li>
	<div>test
	<ul>
	</ul>
	</div>
	</li>
	<li>test</li>
</ul>

In Chrome it is enough to use

<ul>	
	<li>
	<div>test
	<ul>
	</ul>
	</div>
	</li>
</ul>

4. Switch to wysiwyg mode
5. Press Ctrl+A na dclick on Numbered List button

Expected result

No error gets thrown.

Perhaps as an alternative solution such list should be filtered by ACF.

Actual result

JavaScript error gets thrown:
Message: Cannot read property 'parent' of undefined
Line: 319
URI: /ckeditor-dev/plugins/list/plugin.js

Other details

• Browser: Any
• OS: Any
• CKEditor version: 4.0+
• Installed CKEditor plugins: List

---

The Original scenario was:

1. Open https://codepen.io/pratikgolchha/pen/wxGbRd in Edge
2. Copy everything form https://docs.microsoft.com/zh-cn/powerapps/maker/canvas-apps/controls/control-gallery and paste in the CKEditor
3. Select all contents and apply bulleted list and then numbered list
4. Check the console

This document is huge so maybe there is something extra what is causing the same issue (there shouldn't be but it may).

[jswiderski]

This issue could be related: #2438

[msamsel]

Additional markup to check:

<p><br></p><ul></ul><ul><li><a href="https://powerusers.microsoft.com/plugins/common/feature/oauth2sso/sso_login_redirect?referer=https%3A%2F%2Fpowerusers.microsoft.com%2Ft5%2FPowerApps-Community%2Fct-p%2FPowerApps1">Register</a></li><li><br></li><li>·</li><li><br></li><li><a href="https://powerusers.microsoft.com/plugins/common/feature/oauth2sso/sso_login_redirect?referer=https%3A%2F%2Fpowerusers.microsoft.com%2Ft5%2FPowerApps-Community%2Fct-p%2FPowerApps1">Sign In</a></li><li><br></li><li>·</li><li><br></li><li><a href="https://powerusers.microsoft.com/t5/help/faqpage">Help</a></li></ul><p><br></p>

[mlewand]

Fixed with #2440.