Steps to replicate the issue (include links if applicable):
- You have to be logged in to a non-autoconfirmed account at enwiki to get the new user landing page and replicate the issue.
- Go to https://en.wikipedia.org/wiki/Nosuchpage
- Check the target of the link on "search" in "You can also search for an existing article."
What happens?:
The link on "search" is https://en.wikipedia.org/wiki/Special:Search/Badtitle/Message
What should have happened instead?:
The link should have been https://en.wikipedia.org/wiki/Special:Search/Nosuchpage
Other information:
The new user landing page is a feature made with https://www.mediawiki.org/wiki/Extension:ArticleCreationWorkflow
The link is made in https://en.wikipedia.org/wiki/Wikipedia:New_user_landing_page which says:
You can also [[Special:Search/{{PAGENAME}}|search]] for an existing article.{{PAGENAME}} should have produced Nosuchpage on https://en.wikipedia.org/wiki/Nosuchpage but it produces Badtitle/Message. It's very similar to T380519 where FULLPAGENAMEE produced Special:Badtitle/Message in pending changes messages before being fixed.
If https://en.wikipedia.org/wiki/Wikipedia:New_user_landing_page is viewed directly then the link says https://en.wikipedia.org/wiki/Special:Search/New_user_landing_page as expected. The bug happens when the message is applied on another page by ArticleCreationWorkflow.
It appears that ArticleCreationWorkflow is only installed in enwiki, testwiki and test2wiki. Everybody can create mainspace pages in testwiki so the new user landing page may never be shown there. The test2wiki message is made with https://test2.wikipedia.org/wiki/Wikipedia:New_user_landing_page which doesn't currently use {{PAGENAME}} or similar magic words so enwiki is the only place to replicate the issue at the moment. I tested it with an alternative account PrimeHunter3 which isn't autoconfirmed.