Error: TypeError: Cannot read property 'Infobar' of undefined happening in the quibble-vendor-mysql-hhvm-docker job. For example https://integration.wikimedia.org/ci/job/quibble-vendor-mysql-hhvm-docker/41981/console
Happens every time. Other jobs pass. Doing a diff between this job and wmf-quibble-vendor-mysql-hhvm-docker the following extra extensions are present in the failing job (there are also extension not present, but that sounds less likely cause):
mediawiki/extensions/AntiSpoof mediawiki/extensions/ArticlePlaceholder mediawiki/extensions/BetaFeatures mediawiki/extensions/Capiunto mediawiki/extensions/CentralAuth mediawiki/extensions/EducationProgram mediawiki/extensions/LiquidThreads mediawiki/extensions/MassMessage mediawiki/extensions/PropertySuggester mediawiki/extensions/Renameuser mediawiki/extensions/Scribunto mediawiki/extensions/SyntaxHighlight_GeSHi mediawiki/extensions/TitleBlacklist mediawiki/extensions/UserMerge mediawiki/extensions/WikibaseLexeme mediawiki/extensions/WikibaseMediaInfo mediawiki/extensions/WikibaseQualityConstraints mediawiki/extensions/WikimediaBadges mediawiki/extensions/WikimediaEvents
There also messages like Cannot read property 'Translation' of undefined\n at HTMLDivElement coming from jquery.wikibase.entitysearch that are not present in the successful job. That seems a lead... perhaps not the cause but symptom of a common cause, since Wikibase extension is present on both jobs.
Impact: Blocks merges to ContentTranslation