Example build: quibble-vendor-mysql-php72-noselenium-docker #7789, for I2e00d1f515. Also affected PS2 of the same change – so far this seems to be a consistent error that happens on every build.
12:42:30 There were 9 errors: 12:42:30 12:42:30 1) Wikibase\Lexeme\Tests\MediaWiki\Diff\LexemeDiffVisualizerIntegrationTest::testAddedStatementsWithLexemesAsTargetDisplayLemma 12:42:30 === Logs generated by test case 12:42:30 [objectcache] [debug] MainWANObjectCache using store {class} {"class":"EmptyBagOStuff"} 12:42:30 [localisation] [debug] LocalisationCache using store LCStoreNull [] 12:42:30 [localisation] [debug] LocalisationCache using store LCStoreNull [] 12:42:30 [localisation] [debug] LocalisationCache using store LCStoreNull [] 12:42:30 [MessageCache] [debug] MessageCache using store {class} {"class":"HashBagOStuff"} 12:42:30 [objectcache] [debug] MainWANObjectCache using store {class} {"class":"EmptyBagOStuff"} 12:42:30 [Wikibase] [debug] {method}: setting {settingName} was given as a closure, resolve it to {logValue} {"method":"Wikibase\\Lib\\SettingsArray::getSetting","settingName":"conceptBaseUri","logValue":"'http:\/\/127.0.0.1:9412\/entity\/'"} 12:42:30 === 12:42:30 ReflectionException: Property handlers does not exist 12:42:30 12:42:30 /workspace/src/extensions/WikibaseLexeme/tests/phpunit/mediawiki/Diff/LexemeDiffVisualizerIntegrationTest.php:455 12:42:30 /workspace/src/extensions/WikibaseLexeme/tests/phpunit/mediawiki/Diff/LexemeDiffVisualizerIntegrationTest.php:52 12:42:30 /workspace/src/tests/phpunit/MediaWikiIntegrationTestCase.php:424 12:42:30 /workspace/src/maintenance/doMaintenance.php:105
(The other 8 test failures look pretty similar.)