TYPO3 Core

Suppose the following scenario:

1)

A multidomain TYPO3 website serving:

http://www.domain-a.com/
http://www.domain-b.com/

2) BE users access the backend using http://www.domain-a.com/typo3/
3) BE users allowed to edit http://www.domain-b.com/ do NOT have pages of http://www.domain-a.com/ mounted, so they can't see them in the page browser.

If such a BE user wants to link a page in http://www.domain-a.com/ the only way is by inserting an external link. The problem happens when the RTE record is saved to the database:

4) The RTE -> DB transformation converts "<a>" tags into "<link>" tags whenever possible. In this case, the <a> tag with the link (http://www.domain-a.com/wherever/) is converted AND the link itself is converted to a relative link (/wherever/).

5) When the content element is served, the link is converted again into an absolute link but it's wrong. (The link shows http://www.domain-b.com/wherever/ where it should be http://www.domain-a.com/wherever/)

The problem is on step (4) because the link should never become relative.

(issue imported from #M10438)