Error in SMW 4.x

[krabina]

Setup

• MW version: 1.35.5
• DB (MySQL etc.): 10.3.34-MariaDB
• PHP version: 7.4.28
• SMW version: 4.0.1 (fd1b241)
• SRF version: 4.0.1 (44c0bd8)
• Browsers and versions (if applicable):

Issue

Same query working in SMW 3.x is breaks with SMW 4.x
https://www.ogdcockpit.eu/OGD_Cockpit

Stacktrace

[YlQjca-4FYzcjIo8Y-GyswABBw4] /index.php?title=OGD-Cockpit&action=submit TypeError from line 56 of /extensions/ModernTimeline/src/JsonBuilder.php: Argument 1 passed to ModernTimeline\JsonBuilder::newHeadline() must be an instance of Title, null given, called in /extensions/ModernTimeline/src/JsonBuilder.php on line 36

Backtrace:

#0 /extensions/ModernTimeline/src/JsonBuilder.php(36): ModernTimeline\JsonBuilder->newHeadline(NULL)
#1 /extensions/ModernTimeline/src/JsonBuilder.php(27): ModernTimeline\JsonBuilder->buildEvent(ModernTimeline\Event)
#2 /extensions/ModernTimeline/src/TimelinePresenter.php(40): ModernTimeline\JsonBuilder->eventsToTimelineJson(array)
#3 /extensions/ModernTimeline/src/TimelinePresenter.php(32): ModernTimeline\TimelinePresenter->createJsonString(ModernTimeline\ResultFacade\SimpleQueryResult)
#4 /extensions/ModernTimeline/src/ModernTimelinePrinter.php(61): ModernTimeline\TimelinePresenter->presentResult(ModernTimeline\ResultFacade\SimpleQueryResult)
#5 /extensions/SemanticMediaWiki/includes/query/SMW_QueryProcessor.php(348): ModernTimeline\ModernTimelinePrinter->getResult(SMW\Query\QueryResult, array, integer)
#6 /extensions/SemanticMediaWiki/src/ParserFunctions/AskParserFunction.php(364): SMWQueryProcessor::getResultFromQuery(SMWQuery, array, integer, integer)
#7 /extensions/SemanticMediaWiki/src/ParserFunctions/AskParserFunction.php(196): SMW\ParserFunctions\AskParserFunction->doFetchResultsFromFunctionParameters(array, array)
#8 /extensions/SemanticMediaWiki/src/ParserFunctionFactory.php(402): SMW\ParserFunctions\AskParserFunction->parse(array)
#9 /includes/parser/Parser.php(3340): SMW\ParserFunctionFactory->SMW\{closure}(Parser, string, string, string, string, string, string, string, string, string)
#10 /includes/parser/Parser.php(3047): Parser->callParserFunction(PPFrame_Hash, string, array)
#11 /includes/parser/PPFrame_Hash.php(263): Parser->braceSubstitution(array, PPFrame_Hash)
#12 /includes/parser/Parser.php(2887): PPFrame_Hash->expand(PPNode_Hash_Tree, integer)
#13 /includes/parser/Parser.php(1556): Parser->replaceVariables(string)
#14 /includes/parser/Parser.php(651): Parser->internalParse(string)
#15 /includes/content/WikitextContent.php(374): Parser->parse(string, Title, ParserOptions, boolean, boolean, NULL)
#16 /includes/content/AbstractContent.php(590): WikitextContent->fillParserOutput(Title, NULL, ParserOptions, boolean, ParserOutput)
#17 /includes/Revision/RenderedRevision.php(263): AbstractContent->getParserOutput(Title, NULL, ParserOptions, boolean)
#18 /includes/Revision/RenderedRevision.php(235): MediaWiki\Revision\RenderedRevision->getSlotParserOutputUncached(WikitextContent, boolean)
#19 /includes/Revision/RevisionRenderer.php(215): MediaWiki\Revision\RenderedRevision->getSlotParserOutput(string)
#20 /includes/Revision/RevisionRenderer.php(152): MediaWiki\Revision\RevisionRenderer->combineSlotOutput(MediaWiki\Revision\RenderedRevision, array)
#21 [internal function]: MediaWiki\Revision\RevisionRenderer->MediaWiki\Revision\{closure}(MediaWiki\Revision\RenderedRevision, array)
#22 /includes/Revision/RenderedRevision.php(197): call_user_func(Closure, MediaWiki\Revision\RenderedRevision, array)
#23 /includes/Storage/DerivedPageDataUpdater.php(1315): MediaWiki\Revision\RenderedRevision->getRevisionParserOutput()
#24 /includes/Storage/PageUpdater.php(752): MediaWiki\Storage\DerivedPageDataUpdater->getCanonicalParserOutput()
#25 /includes/page/WikiPage.php(2015): MediaWiki\Storage\PageUpdater->saveRevision(CommentStoreComment, integer)
#26 /includes/EditPage.php(2459): WikiPage->doEditContent(WikitextContent, CommentStoreComment, integer, boolean, User, string, array, integer)
#27 /includes/EditPage.php(1726): EditPage->internalAttemptSave(array, boolean)
#28 /includes/EditPage.php(680): EditPage->attemptSave(array)
#29 /includes/actions/EditAction.php(71): EditPage->edit()
#30 /includes/actions/SubmitAction.php(38): EditAction->show()
#31 /includes/MediaWiki.php(532): SubmitAction->show()
#32 /includes/MediaWiki.php(313): MediaWiki->performAction(Article, Title)
#33 /includes/MediaWiki.php(945): MediaWiki->performRequest()
#34 /includes/MediaWiki.php(548): MediaWiki->main()
#35 /index.php(53): MediaWiki->run()
#36 /index.php(46): wfIndexMain()
#37 {main}

[JeroenDeDauw]

This is likely due to SMW return values for a page that no longer exists. Still, the timeline should not break if that happens.