VE does not accept the entry of relative subpage links. In particular, it will not recognize links entered as /subpage or /subpage/. Subpage links must be entered as full links, which defeats the purpose of having relative links that don't break when pages are moved or renamed.
Topic on VisualEditor/Feedback
User:Dave Braunschweig, are you looking only for this? https://www.mediawiki.org/w/index.php?title=User:Whatamidoing_(WMF)/Sandbox&diff=1352736&oldid=1319573
Not exactly. That appears to be a named reference rather than a subpage. Take a look at https://en.wikiversity.org/wiki/IT_Fundamentals for examples. If those subpage links are edited with VisualEditor, they become absolute links rather than relative links.
That's just a link to a subpage: I need a [[/named|named]] reference
(Ignore the contents of the text; it was written for a different round of testing.)
Yes, although the naming of the link isn't necessary when entered as /named/ . It displays correctly without the slashes. There still does not seem to be a way to enter subpage links as relative references.
The relative references are important when the base page is moved. If relative links have been used, everything continues to link correctly. If absolute links are used, all links to subpages must be updated.
This isn't a big deal on Wikipedia, but has significant impact on Wikibooks and Wikiversity, where subpages are the basis for most content.
Thanks for the reply. I think I need to you explain what "does not accept" means. If I open VisualEditor, open the link inspector, and type "/subpage" into the link tool's box, and press Return, then it makes a link to /subpage. Is that not working for you, or is that not what you want?
Sorry, you are correct. It does ultimately work. But it appears not to work while creating the link because it shows up as red rather than blue on an existing subpage. Is it possible to have VE display the link as blue during the edit for existing subpages?
I looked at it for a bit, and it's probably a bit more complicated than I thought. I've filed a bug for it, but it may take longer to fix than I had originally hoped.