Moving a page on wikitech resulted in a fatal error after submission:
2015-12-03 14:52:26 silver labswiki exception ERROR: [71736016] /w/index.php?title=Special:MovePage&action=submit MWException from line 220 of /srv/mediawiki/php-1.27.0-wmf.7/includes/Hooks.php: Detected bug in an extension! Hook SMWParseData::onTitleMoveComplete has invalid call signature; Parameter 3 to SMWParseData::onTitleMoveComplete() expected to be a reference, value given {"exception_id":"71736016"}
[Exception MWException] (/srv/mediawiki/php-1.27.0-wmf.7/includes/Hooks.php:220) Detected bug in an extension! Hook SMWParseData::onTitleMoveComplete has invalid call signature; Parameter 3 to SMWParseData::onTitleMoveComplete() expected to be a reference, value given
#0 /srv/mediawiki/php-1.27.0-wmf.7/includes/MovePage.php(376): Hooks::run(string, array)
#1 [internal function]: MovePage->{closure}()
#2 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/Database.php(3310): call_user_func(Closure)
#3 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/Database.php(3562): DatabaseBase->runOnTransactionIdleCallbacks()
#4 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/loadbalancer/LoadBalancer.php(1050): DatabaseBase->commit(string, string)
#5 [internal function]: LoadBalancer->commitMasterChanges()
#6 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/loadbalancer/LBFactory.php(194): call_user_func_array(array, array)
#7 [internal function]: LBFactory->{closure}(LoadBalancer, string, array)
#8 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/loadbalancer/LBFactoryMulti.php(394): call_user_func_array(Closure, array)
#9 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/loadbalancer/LBFactory.php(195): LBFactoryMulti->forEachLB(Closure, array)
#10 /srv/mediawiki/php-1.27.0-wmf.7/includes/db/loadbalancer/LBFactory.php(212): LBFactory->forEachLBCallMethod(string)
#11 /srv/mediawiki/php-1.27.0-wmf.7/includes/MediaWiki.php(533): LBFactory->commitMasterChanges()
#12 /srv/mediawiki/php-1.27.0-wmf.7/includes/MediaWiki.php(709): MediaWiki->doPreOutputCommit()
#13 /srv/mediawiki/php-1.27.0-wmf.7/includes/MediaWiki.php(506): MediaWiki->main()
#14 /srv/mediawiki/php-1.27.0-wmf.7/index.php(43): MediaWiki->run()
#15 /srv/mediawiki/w/index.php(3): require(string)
#16 {main}It seems the main action (renaming the page in the database) did go through, but it's likely that other secondary updates or notifications maybe broken.