We turned of client-side features for Lexemes for now but seem to have missed a part. (See T195611 for the fallout.)
The problem: someone added a statement to an item that was used on Wikipedia. This statement linked to a Lexeme. This lead to internal errors when viewing the page.
We need to figure out a more graceful way of handling links to Lexemes (and Forms?) in statements that are used on the clien
Current stacktrace:
```
2018-05-25 18:12:37 [WwhSEwpAICMAALKnaggAAABH] mw1333 frwiki 1.32.0-wmf.4 exception ERROR: [WwhSEwpAICMAALKnaggAAABH] /wiki/Cracovie Wikibase\DataModel\Services\Lookup\EntityLookupException from line 44 of /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/RevisionBasedEntityLookup.php: The serialization "L1041" is not recognized by the configured id builders {"exception_id":"WwhSEwpAICMAALKnaggAAABH","exception_url":"/wiki/Cracovie","caught_by":"mwe_handler"}
[Exception Wikibase\DataModel\Services\Lookup\EntityLookupException] (/srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/RevisionBasedEntityLookup.php:44) The serialization "L1041" is not recognized by the configured id builders
#0 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-services/src/Lookup/RedirectResolvingEntityLookup.php(51): Wikibase\Lib\Store\RevisionBasedEntityLookup->getEntity(Wikibase\DataModel\Entity\ItemId)
#1 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/LangLinkHandler.php(109): Wikibase\DataModel\Services\Lookup\RedirectResolvingEntityLookup->getEntity(Wikibase\DataModel\Entity\ItemId)
#2 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/LangLinkHandler.php(331): Wikibase\Client\LangLinkHandler->getEntityLinks(Title)
#3 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/LangLinkHandler.php(352): Wikibase\Client\LangLinkHandler->getEffectiveRepoLinks(Title, ParserOutput)
#4 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/Hooks/ParserOutputUpdateHookHandlers.php(97): Wikibase\Client\LangLinkHandler->addLinksFromRepository(Title, ParserOutput)
#5 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/Hooks/ParserOutputUpdateHookHandlers.php(65): Wikibase\Client\Hooks\ParserOutputUpdateHookHandlers->doContentAlterParserOutput(Title, ParserOutput)
#6 /srv/mediawiki/php-1.32.0-wmf.4/includes/Hooks.php(177): Wikibase\Client\Hooks\ParserOutputUpdateHookHandlers::onContentAlterParserOutput(WikitextContent, Title, ParserOutput)
#7 /srv/mediawiki/php-1.32.0-wmf.4/includes/Hooks.php(205): Hooks::callHook(string, array, array, NULL)
#8 /srv/mediawiki/php-1.32.0-wmf.4/includes/content/AbstractContent.php(520): Hooks::run(string, array)
#9 /srv/mediawiki/php-1.32.0-wmf.4/includes/poolcounter/PoolWorkArticleView.php(145): AbstractContent->getParserOutput(Title, integer, ParserOptions)
#10 /srv/mediawiki/php-1.32.0-wmf.4/includes/poolcounter/PoolCounterWork.php(123): PoolWorkArticleView->doWork()
#11 /srv/mediawiki/php-1.32.0-wmf.4/includes/page/Article.php(604): PoolCounterWork->execute()
#12 /srv/mediawiki/php-1.32.0-wmf.4/includes/actions/ViewAction.php(68): Article->view()
#13 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(500): ViewAction->show()
#14 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title)
#15 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(861): MediaWiki->performRequest()
#16 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(524): MediaWiki->main()
#17 /srv/mediawiki/php-1.32.0-wmf.4/index.php(42): MediaWiki->run()
#18 /srv/mediawiki/w/index.php(3): include(string)
#19 {main}
Caused by: [Exception Wikibase\DataModel\Entity\EntityIdParsingException] (/srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model/src/Entity/DispatchingEntityIdParser.php:60) The serialization "L1041" is not recognized by the configured id builders
#0 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-services/src/EntityId/PrefixMappingEntityIdParser.php(86): Wikibase\DataModel\Entity\DispatchingEntityIdParser->parse(string)
#1 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Serialization/RepositorySpecificDataValueDeserializerFactory.php(70): Wikibase\DataModel\Services\EntityId\PrefixMappingEntityIdParser->parse(string)
#2 /srv/mediawiki/php-1.32.0-wmf.4/vendor/data-values/serialization/src/Deserializers/DataValueDeserializer.php(122): Closure$Wikibase\Lib\Serialization\RepositorySpecificDataValueDeserializerFactory::newDeserializerForRepository(array)
#3 /srv/mediawiki/php-1.32.0-wmf.4/vendor/data-values/serialization/src/Deserializers/DataValueDeserializer.php(91): DataValues\Deserializers\DataValueDeserializer->getDeserialization(array)
#4 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/SnakDeserializer.php(118): DataValues\Deserializers\DataValueDeserializer->deserialize(array)
#5 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/SnakDeserializer.php(108): Wikibase\DataModel\Deserializers\SnakDeserializer->deserializeDataValue(array)
#6 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/SnakDeserializer.php(90): Wikibase\DataModel\Deserializers\SnakDeserializer->newValueSnak(array)
#7 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/SnakDeserializer.php(72): Wikibase\DataModel\Deserializers\SnakDeserializer->getDeserialized(array)
#8 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/SnakListDeserializer.php(60): Wikibase\DataModel\Deserializers\SnakDeserializer->deserialize(array)
#9 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/SnakListDeserializer.php(41): Wikibase\DataModel\Deserializers\SnakListDeserializer->getDeserialized(array)
#10 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/StatementDeserializer.php(140): Wikibase\DataModel\Deserializers\SnakListDeserializer->deserialize(array)
#11 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/StatementDeserializer.php(118): Wikibase\DataModel\Deserializers\StatementDeserializer->setQualifiersFromSerialization(array, Wikibase\DataModel\Statement\Statement)
#12 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/StatementDeserializer.php(100): Wikibase\DataModel\Deserializers\StatementDeserializer->getDeserialized(array)
#13 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/StatementListDeserializer.php(60): Wikibase\DataModel\Deserializers\StatementDeserializer->deserialize(array)
#14 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/StatementListDeserializer.php(41): Wikibase\DataModel\Deserializers\StatementListDeserializer->getDeserialized(array)
#15 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/ItemDeserializer.php(130): Wikibase\DataModel\Deserializers\StatementListDeserializer->deserialize(array)
#16 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/ItemDeserializer.php(85): Wikibase\DataModel\Deserializers\ItemDeserializer->setStatementListFromSerialization(array, Wikibase\DataModel\Entity\Item)
#17 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-serialization/src/Deserializers/ItemDeserializer.php(77): Wikibase\DataModel\Deserializers\ItemDeserializer->getDeserialized(array)
#18 /srv/mediawiki/php-1.32.0-wmf.4/vendor/serialization/serialization/src/Deserializers/DispatchingDeserializer.php(42): Wikibase\DataModel\Deserializers\ItemDeserializer->deserialize(array)
#19 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/internal-serialization/src/Deserializers/EntityDeserializer.php(47): Deserializers\DispatchingDeserializer->deserialize(array)
#20 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/EntityContentDataCodec.php(252): Wikibase\InternalSerialization\Deserializers\EntityDeserializer->deserialize(array)
#21 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/Sql/WikiPageEntityRevisionLookup.php(163): Wikibase\Lib\Store\EntityContentDataCodec->decodeEntity(string, NULL)
#22 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/Sql/WikiPageEntityRevisionLookup.php(92): Wikibase\Lib\Store\Sql\WikiPageEntityRevisionLookup->loadEntity(stdClass)
#23 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/DispatchingEntityRevisionLookup.php(59): Wikibase\Lib\Store\Sql\WikiPageEntityRevisionLookup->getEntityRevision(Wikibase\DataModel\Entity\ItemId, integer, string)
#24 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/CachingEntityRevisionLookup.php(104): Wikibase\Lib\Store\DispatchingEntityRevisionLookup->getEntityRevision(Wikibase\DataModel\Entity\ItemId, integer, string)
#25 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/CachingEntityRevisionLookup.php(87): Wikibase\Lib\Store\CachingEntityRevisionLookup->fetchEntityRevision(Wikibase\DataModel\Entity\ItemId, integer, string)
#26 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/CachingEntityRevisionLookup.php(104): Wikibase\Lib\Store\CachingEntityRevisionLookup->getEntityRevision(Wikibase\DataModel\Entity\ItemId, integer, string)
#27 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/CachingEntityRevisionLookup.php(87): Wikibase\Lib\Store\CachingEntityRevisionLookup->fetchEntityRevision(Wikibase\DataModel\Entity\ItemId, integer, string)
#28 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/lib/includes/Store/RevisionBasedEntityLookup.php(39): Wikibase\Lib\Store\CachingEntityRevisionLookup->getEntityRevision(Wikibase\DataModel\Entity\ItemId)
#29 /srv/mediawiki/php-1.32.0-wmf.4/vendor/wikibase/data-model-services/src/Lookup/RedirectResolvingEntityLookup.php(51): Wikibase\Lib\Store\RevisionBasedEntityLookup->getEntity(Wikibase\DataModel\Entity\ItemId)
#30 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/LangLinkHandler.php(109): Wikibase\DataModel\Services\Lookup\RedirectResolvingEntityLookup->getEntity(Wikibase\DataModel\Entity\ItemId)
#31 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/LangLinkHandler.php(331): Wikibase\Client\LangLinkHandler->getEntityLinks(Title)
#32 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/LangLinkHandler.php(352): Wikibase\Client\LangLinkHandler->getEffectiveRepoLinks(Title, ParserOutput)
#33 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/Hooks/ParserOutputUpdateHookHandlers.php(97): Wikibase\Client\LangLinkHandler->addLinksFromRepository(Title, ParserOutput)
#34 /srv/mediawiki/php-1.32.0-wmf.4/extensions/Wikibase/client/includes/Hooks/ParserOutputUpdateHookHandlers.php(65): Wikibase\Client\Hooks\ParserOutputUpdateHookHandlers->doContentAlterParserOutput(Title, ParserOutput)
#35 /srv/mediawiki/php-1.32.0-wmf.4/includes/Hooks.php(177): Wikibase\Client\Hooks\ParserOutputUpdateHookHandlers::onContentAlterParserOutput(WikitextContent, Title, ParserOutput)
#36 /srv/mediawiki/php-1.32.0-wmf.4/includes/Hooks.php(205): Hooks::callHook(string, array, array, NULL)
#37 /srv/mediawiki/php-1.32.0-wmf.4/includes/content/AbstractContent.php(520): Hooks::run(string, array)
#38 /srv/mediawiki/php-1.32.0-wmf.4/includes/poolcounter/PoolWorkArticleView.php(145): AbstractContent->getParserOutput(Title, integer, ParserOptions)
#39 /srv/mediawiki/php-1.32.0-wmf.4/includes/poolcounter/PoolCounterWork.php(123): PoolWorkArticleView->doWork()
#40 /srv/mediawiki/php-1.32.0-wmf.4/includes/page/Article.php(604): PoolCounterWork->execute()
#41 /srv/mediawiki/php-1.32.0-wmf.4/includes/actions/ViewAction.php(68): Article->view()
#42 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(500): ViewAction->show()
#43 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title)
#44 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(861): MediaWiki->performRequest()
#45 /srv/mediawiki/php-1.32.0-wmf.4/includes/MediaWiki.php(524): MediaWiki->main()
#46 /srv/mediawiki/php-1.32.0-wmf.4/index.php(42): MediaWiki->run()
#47 /srv/mediawiki/w/index.php(3): include(string)
#48 {main}
```