Preserve initial space for HTML element if there is no text node in parent element

[beatadelura]

Are you reporting a feature request or a bug?

Bug. This issue is related to #605 .

Provide detailed reproduction steps (if any)

1. Go to https://jsfiddle.net/cf5d457L/5/
2. Click Source button
3. Input <p><span> lorem </span>ipsum</p>
4. Switch to WYSIWYG mode
5. Click Source button

Expected result

There is an empty space before text lorem:
<p><span> lorem </span>ipsum</p>

Actual result

An empty space has been missed before lorem text.
<p><span>lorem </span>ipsum</p>

Please note, if you put any word before span element, like:
<p>lorem<span> lorem </span>ipsum</p> it works fine.

Other details

• Browser: Chrome Version 60.0.3112.90
• OS: macOS
• CKEditor version: 4.7.1

This is a core issue. It's happening because of code https://github.com/ckeditor/ckeditor-dev/blob/master/core/htmlparser/fragment.js#L401

[Comandeer]

This is more general issue, connected with nearly all HTML elements, not only inline widgets.

It occurs in several places:

• editor.insertHtml calls;
• toDataFormat event;
• manually passing HTML to dataProcessor;
• manually parsing HTML using htmlParser.fragment;
• manually writing HTML using htmlParser.basicWriter.

In fact it's probably present in every place involving data processing.

More straightforward demo: http://jsfiddle.net/Comandeer/nu1wm3L8/