Ordering problem when block quote is being inserted into the middle of the list

[dufipl]

📝 Provide detailed reproduction steps (if any)

1. Prepare six lines of text
2. Create numbered list (one number for each text line)
3. Select lines 3 and 4 and add a "Block quote"
4. Change the order of the list in the block quote.

✔️ Expected result

Order changes only in the block quoted list.

❌ Actual result

Order changes are also in the list below.

Changing the order of the list above or below the block quote impacts only desired list.

📃 Other details

Browser: Chrome, Firefox, Safari
OS: Mac Os Monterey
First affected CKEditor version: 31.1.0

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[CatStrategist]

Possible issue is in a getSiblingNodes() in list utils.

[t-mangoe]

I did some research on this issue.
It seems that when a block quote is inserted, the ol tag that makes up the list is split into two.
It looks like this.

Before inserting:

<ol>
  <li>aaa</li>
  <li>bbb</li>
  <li>ccc</li>
  <li>ddd</li>
</ol>

After inserting:

<ol>
  <li>aaa</li>
  <li>bbb</li>
</ol>
<blockquote>block quoting<blockquote>
<ol>
  <!-- the order of the list is restarted from the beginning. -->
  <li>ccc</li>
  <li>ddd</li>
</ol>

It may be necessary to prevent the ol tag from being split into two.

[Reinmar]

Usually we use Schema#getSelectedBlocks() that trims the trailing block if the selection starts at the very beginning of it. Here, as you can see, blockquote uses this method but there's a chance that the "reversed order" feature does not. Disclaimer: I haven't seen any code, just base on my experience.