Typing's undo step should be broken by applying an attribute

[Reinmar]

1. Open http://tests.ckeditor.dev:1030/build/amd/tests/basic-styles/manual/basic-styles
2. Type few letters (make sure to type in a place where italic isn't applied).
3. Press italic button.
4. Type few more letters.
5. Press undo button.

Only the letters typed in step 4 should be undone.

This issue is very similar to #3042. Changing selection attributes should reset a buffer, just like moving the selection should.

[maxbarnas]

I noticed, that undo operation deletes just part of the text typed in step 4 above, when typed text is quite long (dozen or more characters).

[Reinmar]

That's the expected result. It's so called undo step – https://github.com/ckeditor/ckeditor5-typing/blob/7c446342e8a742b77ab260ad4a7f22d51b58e0b8/src/input.js#L36

[maxbarnas]

I kind of suspected this. Thanks for pointing out the actual piece of code responsible for that.

[maxbarnas]

Prototype of solution is available in t/21 branch.

Listener of changesDone event wraps all the change:attribute events to allow proper unlocking ChangeBuffer.

Listening to change:range does not affect the fix, nor locking buffer in ChangeBuffer#_handleKeydown.

This prototype also fixes problem when changing selection: https://github.com/ckeditor/ckeditor5-typing/issues/20.

[f1ames]

Pushed changes to t/21. The only thing missing are unit/integration input tests. Since ckeditor/ckeditor5-typing#48 with InputCommand should be ready soon, I am not sure if it makes sense to create missing tests now without it and then rewrite it using InputCommand.

[f1ames]

Noticed https://github.com/ckeditor/ckeditor5-undo/issues/58.