Restricted editing in tables crash

[FilipTokarski]

📝 Provide detailed reproduction steps (if any)

1. Create a table in standard mode
2. Add some text in a table cell using exception marker
3. Switch to restricted mode
4. Try to type something in the same cell

✔️ Expected result

Exception marker should contain the provided text. User should not be able to write anywhere else in the table.

❌ Actual result

Exception marker splits into two parts, losing its text content, app crashes.

📃 Other details

• Browser: any
• OS: any
• CKEditor version: 5

Error when trying to type in the 'restricted' cell:

Uncaught TypeError: element.getCustomProperty(...) is not a function
    at DowncastDispatcher.<anonymous> (downcasthelpers.js:1053)
    at DowncastDispatcher.fire (emittermixin.js:209)
    at DowncastDispatcher.convertMarkerRemove (downcastdispatcher.js:386)
    at DowncastDispatcher.convertChanges (downcastdispatcher.js:131)
    at editingcontroller.js:92
    at View.change (view.js:468)
    at Document.EditingController.listenTo.priority (editingcontroller.js:91)
    at Document.fire (emittermixin.js:209)
    at Document._handleChangeBlock (document.js:318)
    at Model._runPendingChanges (model.js:787)

And then when trying to type anywhere else in the table:

ckeditorerror.js:66 Uncaught CKEditorError: model-nodelist-offset-out-of-bounds: Given offset cannot be found in the node list. Read more: https://ckeditor.com/docs/ckeditor5/latest/framework/guides/support/error-codes.html#error-model-nodelist-offset-out-of-bounds
 {"offset":2,"nodeList":[{"data":" "}]}
    at NodeList.offsetToIndex (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:52699:10)
    at Element.offsetToIndex (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:49710:25)
    at Position.get index [as index] (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:57800:22)
    at Position.get textNode [as textNode] (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:57811:43)
    at validateTextNodePosition (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:47894:33)
    at Document._validateSelectionRange (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:47803:10)
    at LiveSelection.<anonymous> (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:48971:26)
    at LiveSelection.fire (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:113448:30)
    at LiveSelection._setRanges (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:61898:8)
    at LiveSelection.setTo (http://localhost:8125/ckeditor5-restricted-editing/tests/manual/restrictedediting.js:61789:9)

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If you'd like to see this fixed sooner, add a 👍 reaction to this post.

[Mgsy]

I can confirm this issue.

[Reinmar]

cc @jodator

[jodator]

There's something wrong with upcast conversion.

<figure className="table">
	<table>
		<tbody>
			<tr>
				<td><span className="restricted-editing-exception">asdfadsf</span></td>
			</tr>
		</tbody>
	</table>
</figure>

Similar thing happens for marker inside caption element.