Issue: Redirects not imported as synonyms

Please also see bug report 301121 which is about a redirect to a category page not being imported and has resulted in a broken link.

Regarding 301120, I believe this is the expected behavior, since there is no article "Wiki Articles:Specific Title" (the synonym target), just "Specific Title". Maybe this worked in VW3 if the "Wiki Articles:" namespace was the name for the default namespace (""). But this will not work in VW4 unless there is a synonym for "Wiki Articles:Specific Title" => "Specific Title". We could add a step to massively create such redirects during a VW3 import, but I'm not sure the benefit outweighs the data created -- the former format was rare and was always a 301 response in VW3 from what I remember (it is unreasonable to maintain 301 responses indefinitely). Even if we did create the missing redirect, in this case it would be considered a double-redirect, so the redirect would still not work...

For the case of 301121, it looks like this synonym is correctly broken, because it was once a redirect to itself. This could happen if you renamed the target article multiple times, especially if it was renamed back to a previous title.

The Special:ListRedirects page will give you a better sense of whether redirects are turning into synonyms correctly or not. But for the examples listed in the linked threads, I don't see an obvious issue.

Regarding 301120: in VW3 this was a common way to redirect to a category. IIRC all our redirects to categories are setup this way.
it would be beneficial if redirects to categories are imported as category synonyms. Not as 301 redirects.

I think we can resolve this by making something like a Prefix Synonym -- other prefixes that point to a canonical prefix. In this case, "Wiki Articles" would point to "[No Prefix]". We can handle the redirects internally and require that prefix synonyms only point to real prefixes, so there should be no double-redirect issue.

That would be good.

Marking this as fixed in the next release. The VW3 default namespace title is now imported as an internal alias for [No Prefix].