Currently on the beta cluster, e.g. here: https://de.wikipedia.beta.wmflabs.org/w/index.php?title=TabellenTest&stable=1
[ZnKErfFC6F8ObEoF4FNawQAAAAc] /w/index.php?stable=1&title=TabellenTest InvalidArgumentException: LinksMigration config 769 on pagelinks table is not supported anymore Backtrace: from /srv/mediawiki/php-master/includes/linker/LinksMigration.php(171) #0 /srv/mediawiki/php-master/includes/linker/LinksMigration.php(113): MediaWiki\Linker\LinksMigration->assertMapping(string) #1 /srv/mediawiki/php-master/extensions/FlaggedRevs/includes/backend/FRDependencyUpdate.php(212): MediaWiki\Linker\LinksMigration->getQueryInfo(string) #2 /srv/mediawiki/php-master/extensions/FlaggedRevs/includes/backend/FRDependencyUpdate.php(45): FRDependencyUpdate->getCurrentVersionLinks() #3 /srv/mediawiki/php-master/extensions/FlaggedRevs/includes/frontend/FlaggablePageView.php(641): FRDependencyUpdate->doUpdate(integer) #4 /srv/mediawiki/php-master/extensions/FlaggedRevs/includes/frontend/FlaggablePageView.php(317): FlaggablePageView->showStableVersion(FlaggedRevision, string, string) #5 /srv/mediawiki/php-master/extensions/FlaggedRevs/includes/frontend/FlaggedRevsUIHooks.php(248): FlaggablePageView->setPageContent(NULL, boolean) #6 /srv/mediawiki/php-master/includes/HookContainer/HookContainer.php(159): FlaggedRevsUIHooks->onArticleViewHeader(Article, NULL, boolean) #7 /srv/mediawiki/php-master/includes/HookContainer/HookRunner.php(861): MediaWiki\HookContainer\HookContainer->run(string, array) #8 /srv/mediawiki/php-master/includes/page/Article.php(610): MediaWiki\HookContainer\HookRunner->onArticleViewHeader(Article, NULL, boolean) #9 /srv/mediawiki/php-master/includes/page/Article.php(539): Article->generateContentOutput(MediaWiki\User\User, ParserOptions, integer, MediaWiki\Output\OutputPage, array) #10 /srv/mediawiki/php-master/includes/actions/ViewAction.php(78): Article->view() #11 /srv/mediawiki/php-master/includes/actions/ActionEntryPoint.php(731): ViewAction->show() #12 /srv/mediawiki/php-master/includes/actions/ActionEntryPoint.php(508): MediaWiki\Actions\ActionEntryPoint->performAction(Article, MediaWiki\Title\Title) #13 /srv/mediawiki/php-master/includes/actions/ActionEntryPoint.php(145): MediaWiki\Actions\ActionEntryPoint->performRequest() #14 /srv/mediawiki/php-master/includes/MediaWikiEntryPoint.php(200): MediaWiki\Actions\ActionEntryPoint->execute() #15 /srv/mediawiki/php-master/index.php(58): MediaWiki\MediaWikiEntryPoint->run() #16 /srv/mediawiki/w/index.php(3): require(string) #17 {main}
The only open ticket I can find related to this is T299947: Normalize pagelinks table.
I suspect a misconfiguration on the beta cluster, but it could also be a mistake in the code. 769 is 0x301, which is SCHEMA_COMPAT_READ_NEW + SCHEMA_COMPAT_WRITE_NEW + SCHEMA_COMPAT_WRITE_OLD. The code I can find via VPS-project-Codesearch (e.g. here) makes it look like SCHEMA_COMPAT_WRITE_OLD got deprecated (via https://gerrit.wikimedia.org/r/1043756) while still being enabled by default?
I'm afraid this could even affect production the moment it is rolled out. I'm going to mark this as a candidate for UBN because of this.