Cut, copy and paste create additional undo step

[Mgsy]

🐞 Is this a bug report or feature request? (choose one)

• Bug report

💻 Version of CKEditor

Latest master.

📋 Steps to reproduce

1. Go to http://localhost:8125/ckeditor5-core/tests/manual/article.html.
2. Select some word.
3. Cut it.
4. Undo.

✅ Expected result

There is only one undo step.

❎ Actual result

There are two undo steps. After performing second undo, editor crashes.

📃 Other details that might be useful

GIF

Error

ckeditorerror.js:46 Uncaught CKEditorError: model-history-wrong-version: Given base version points to the middle of a delta. Read more: https://ckeditor5.github.io/docs/nightly/ckeditor5/latest/framework/guides/support/error-codes.html#model-history-wrong-version
    at History._getIndex (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:48363:10)
    at History.getDeltas (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:48265:24)
    at getDeltas.next (<anonymous>)
    at transformRangesByDeltas (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:36548:14)
    at transformSelectionRange (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:36523:22)
    at UndoCommand._restoreSelection (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:36440:30)
    at Object.editor.model.enqueueChange [as callback] (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:54118:9)
    at Model._runPendingChanges (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:66437:58)
    at Model.enqueueChange (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:66417:9)
    at UndoCommand.execute (http://192.168.20.71:8125/ckeditor5-core/tests/manual/article.js:54114:21)

Notes
Here is first bad commit - b279e7e

Other information
OS: Windows 10, macOS X
Browser: All browsers

[Mgsy]

It turned out that it's not only cut. If you try to copy some word or paste something, additional undo step will appear.

[Reinmar]

Here is first bad commit - b279e7e

While this is a bit strange, I confirmed that this is the first bad revision. Unfortunately, we've been merging so many things at that moment (e.g. license updates) that it didn't help in understanding what caused the problem.

[Reinmar]

I confirmed that this issue can be reproduced with only the EssentialPreset so most likely, the issue is caused by...

• ckeditor/ckeditor5-engine@f56bddf
• ckeditor/ckeditor5-typing@8a4c498
• ckeditor/ckeditor5-undo@325a684

Which doesn't help at all.

[scofalik]

The bug is caused by non-document operations that create an (empty) undo step, while they shouldn't. I am on it.

[scofalik]

Will be fixed by ckeditor/ckeditor5-undo#80