As in https://bugzilla.wikimedia.org/show_bug.cgi?id=58640 described, mediawiki <=1.22 doesn't work with libpcre-8.34 so dependencies should block this. Reproducible: Always
Looks like you are mixing the stable and unstable branch.
(In reply to Jeroen Roovers from comment #1) > Looks like you are mixing the stable and unstable branch. www-apps/mediawiki-1.22 and dev-libs/libpcre-8.34 are both unstable. What am I mixing?
this has been fixed in mediawiki-1.22.1, older branches are unlikely to get fixed.
Closing since this has been fixed in recent versions as mentioned in comment 3.