On latest versions of CommentStreams and SemanticMediaWiki, when a wiki with following configurations:
$wgLocalisationCacheConf = [ 'class' => LocalisationCache::class, 'store' => 'array', 'storeClass' => false, 'storeServer' => [], 'forceRecache' => false, 'storeDirectory' => __DIR__ . "/cache/l10n", 'manualRecache' => true, ];
then run rebuildLocalisationCache maintenance script, the following exceptions will happen:
SMW\Exception\SiteLanguageChangeException from line 243 of /var/www/wiki/w/extensions/SemanticMediaWiki/src/NamespaceManager.php: A change to the `wgLanguageCode` was detected showing a discrepancy (de, en) and is preventing Semantic MediaWiki from modifying related namespace settings.
LocalSettings.php should only contain one `wgLanguageCode` definition and the declaration should happen before `enableSemantics`.
#0 /var/www/wiki/w/extensions/SemanticMediaWiki/src/NamespaceManager.php(200): SMW\NamespaceManager->getLanguageCode()
#1 /var/www/wiki/w/extensions/SemanticMediaWiki/src/NamespaceManager.php(92): SMW\NamespaceManager::initCustomNamespace()
#2 /var/www/wiki/w/extensions/SemanticMediaWiki/src/MediaWiki/Hooks.php(221): SMW\NamespaceManager::initCanonicalNamespaces()
#3 /var/www/wiki/w/includes/Hooks.php(174): SMW\MediaWiki\Hooks::SMW\MediaWiki\{closure}()
#4 /var/www/wiki/w/includes/Hooks.php(202): Hooks::callHook()
#5 /var/www/wiki/w/includes/title/NamespaceInfo.php(356): Hooks::run()
#6 /var/www/wiki/w/languages/Language.php(487): NamespaceInfo->getCanonicalNamespaces()
#7 /var/www/wiki/w/languages/Language.php(563): Language->getNamespaces()
#8 /var/www/wiki/w/includes/title/MediaWikiTitleCodec.php(108): Language->getNsText()
#9 /var/www/wiki/w/includes/title/MediaWikiTitleCodec.php(138): MediaWikiTitleCodec->getNamespaceName()
#10 /var/www/wiki/w/includes/title/MediaWikiTitleCodec.php(266): MediaWikiTitleCodec->formatTitle()
#11 /var/www/wiki/w/includes/cache/LinkCache.php(246): MediaWikiTitleCodec->getPrefixedDBkey()
#12 /var/www/wiki/w/includes/Title.php(3142): LinkCache->addLinkObj()
#13 /var/www/wiki/w/includes/Revision/RevisionRecord.php(109): Title->getArticleID()
#14 /var/www/wiki/w/includes/Revision/RevisionStoreRecord.php(64): MediaWiki\Revision\RevisionRecord->__construct()
#15 /var/www/wiki/w/includes/Revision/RevisionStore.php(1893): MediaWiki\Revision\RevisionStoreRecord->__construct()
#16 /var/www/wiki/w/includes/Revision/RevisionStore.php(1816): MediaWiki\Revision\RevisionStore->newRevisionFromRowAndSlots()
#17 /var/www/wiki/w/includes/Revision/RevisionStore.php(2538): MediaWiki\Revision\RevisionStore->newRevisionFromRow()
#18 /var/www/wiki/w/includes/Revision/RevisionStore.php(1513): MediaWiki\Revision\RevisionStore->loadRevisionFromConds()
#19 /var/www/wiki/w/includes/Revision.php(139): MediaWiki\Revision\RevisionStore->getRevisionByTitle()
#20 /var/www/wiki/w/extensions/Gadgets/includes/MediaWikiGadgetsDefinitionRepo.php(139): Revision::newFromTitle()
#21 /var/www/wiki/w/extensions/Gadgets/includes/MediaWikiGadgetsDefinitionRepo.php(108): MediaWikiGadgetsDefinitionRepo->fetchStructuredList()
#22 /var/www/wiki/w/includes/libs/objectcache/wancache/WANObjectCache.php(1423): MediaWikiGadgetsDefinitionRepo->{closure}()
#23 /var/www/wiki/w/includes/libs/objectcache/wancache/WANObjectCache.php(1278): WANObjectCache->fetchOrRegenerate()
#24 /var/www/wiki/w/extensions/Gadgets/includes/MediaWikiGadgetsDefinitionRepo.php(115): WANObjectCache->getWithSetCallback()
#25 /var/www/wiki/w/extensions/Gadgets/includes/MediaWikiGadgetsDefinitionRepo.php(31): MediaWikiGadgetsDefinitionRepo->loadGadgets()
#26 /var/www/wiki/w/extensions/Gadgets/includes/GadgetHooks.php(134): MediaWikiGadgetsDefinitionRepo->getGadgetIds()
#27 /var/www/wiki/w/includes/Hooks.php(174): GadgetHooks::registerModules()
#28 /var/www/wiki/w/includes/Hooks.php(202): Hooks::callHook()
#29 /var/www/wiki/w/includes/ServiceWiring.php(690): Hooks::run()
#30 /var/www/wiki/w/includes/libs/services/ServiceContainer.php(458): Wikimedia\Services\ServiceContainer->{closure}()
#31 /var/www/wiki/w/includes/libs/services/ServiceContainer.php(427): Wikimedia\Services\ServiceContainer->createService()
#32 /var/www/wiki/w/includes/MediaWikiServices.php(901): Wikimedia\Services\ServiceContainer->getService()
#33 /var/www/wiki/w/maintenance/rebuildLocalisationCache.php(98): MediaWiki\MediaWikiServices->getResourceLoader()
#34 /var/www/wiki/w/includes/cache/localisation/LocalisationCache.php(1049): RebuildLocalisationCache->{closure}()
#35 /var/www/wiki/w/includes/cache/localisation/LocalisationCacheBulkLoad.php(100): LocalisationCache->recache()
#36 /var/www/wiki/w/maintenance/rebuildLocalisationCache.php(178): LocalisationCacheBulkLoad->recache()
#37 /var/www/wiki/w/maintenance/rebuildLocalisationCache.php(138): RebuildLocalisationCache->doRebuild()
#38 /var/www/wiki/w/maintenance/doMaintenance.php(99): RebuildLocalisationCache->execute()
#39 /var/www/wiki/w/maintenance/rebuildLocalisationCache.php(197): require_once('/var/www/wiki/w...')
#40 {main}I'm not sure whether it is CommentStreams or SMW causing this exception, but when I removed
wfLoadExtension ( 'CommentStreams' );, everything went well.

