I upgraded the wiki farm that I run, Referata (referata.com) from MW 1.25 to 1.30 yesterday. Unfortunately, now sessions are mostly no longer working - if you log in, you immediately get logged out again, because there's no preservation of sessions. I say "mostly" because sessions work fine on the main subdomain, www.referata.com (which is also accessible at referata.com). But on every other subdomain, they don't work. Is there any setting I can change to make this more likely to work? Or is there an easy way to move session handling back to what it was before? Even a hack is fine - I just want this problem fixed.
Topic on Project:Support desk
Just guesses, but: Do captured HTTP requests and responses reveal any issues? Any custom code in place that might not have been ported to SessionManager/AuthManager?
I can't find any references to sessions (like session_start(), $_SESSION, etc.) in any of the wiki farm's custom code. And I don't know how to analyze the HTTP stuff to look for session information.
As a starting point try setting $wgSessionCacheType = CACHE_DB;
Also see Topic:T7irqyk4rhfy3ohk.
Unfortunately, that didn't work for me - I also tried adding "$wgMainCacheType = CACHE_ANYTHING;", but that didn't seem to have an effect either. Thank you, though.
(I just downgraded Referata to MediaWiki 1.26, so this problem is gone for now - but it would be good to know of a fix so that I can upgrade in the future.)