on master, with the invalid value specified in bug 49417, I get an exception and stack trace and cannot view my item at all. It makes the item completely unusable.

these invalid time values exist in Wikidata already. there needs to be a way to remove them, including IMHO from the UI.

I tried the remove claim api module and it "seems" to have worked but then I still get the stack trace so I guess not worked.

Unexpected non-MediaWiki exception encountered, of type "DataValues\IllegalValueException"
exception 'DataValues\IllegalValueException' with message '$time needs to be a valid ISO 8601 date' in /var/www/common/wikibase-repo/extensions/DataValues/DataValues/includes/values/TimeValue.php:126
Stack trace:
#0 /var/www/common/wikibase-repo/extensions/DataValues/DataValues/includes/values/TimeValue.php(329): DataValues\TimeValue->__construct('+00000001940-10...', 0, 0, 0, 11, 'http://www.wiki...')
#1 /var/www/common/wikibase-repo/extensions/DataValues/DataValues/includes/DataValueFactory.php(102): DataValues\TimeValue::newFromArray(Array)
#2 /var/www/common/wikibase-repo/extensions/Wikibase/DataModel/DataModel/Snak/SnakObject.php(170): DataValues\DataValueFactory->newDataValue('time', Array)
#3 /var/www/common/wikibase-repo/extensions/Wikibase/DataModel/DataModel/Claim/Claim.php(205): Wikibase\SnakObject::newFromArray(Array)
#4 /var/www/common/wikibase-repo/extensions/Wikibase/DataModel/DataModel/Claim/Statement.php(174): Wikibase\Claim::newFromArray(Array)
#5 /var/www/common/wikibase-repo/extensions/Wikibase/DataModel/DataModel/Claim/Claim.php(202): Wikibase\Statement::newFromArray(Array)
#6 /var/www/common/wikibase-repo/extensions/Wikibase/DataModel/DataModel/Entity/Entity.php(722): Wikibase\Claim::newFromArray(Array)
#7 /var/www/common/wikibase-repo/extensions/Wikibase/DataModel/DataModel/Entity/Entity.php(705): Wikibase\Entity->unstubClaims()
#8 /var/www/common/wikibase-repo/extensions/Wikibase/repo/includes/EntityView.php(218): Wikibase\Entity->getClaims()
#9 /var/www/common/wikibase-repo/extensions/Wikibase/repo/includes/content/ItemContent.php(286): Wikibase\EntityView->getParserOutput(Object(Wikibase\ItemContent), Object(ParserOptions), true)
#10 /var/www/common/wikibase-repo/includes/WikiPage.php(3424): Wikibase\ItemContent->getParserOutput(Object(Title), 1138, Object(ParserOptions))
#11 /var/www/common/wikibase-repo/includes/PoolCounter.php(222): PoolWorkArticleView->doWork()
#12 /var/www/common/wikibase-repo/includes/Article.php(708): PoolCounterWork->execute()
#13 /var/www/common/wikibase-repo/extensions/Wikibase/repo/includes/actions/ViewEntityAction.php(193): Article->view()
#14 /var/www/common/wikibase-repo/extensions/Wikibase/repo/includes/actions/ViewEntityAction.php(123): Wikibase\ViewEntityAction->displayEntityContent(Object(Wikibase\ItemContent))
#15 /var/www/common/wikibase-repo/includes/Wiki.php(439): Wikibase\ViewEntityAction->show()
#16 /var/www/common/wikibase-repo/includes/Wiki.php(305): MediaWiki->performAction(Object(Article), Object(Title))
#17 /var/www/common/wikibase-repo/includes/Wiki.php(565): MediaWiki->performRequest()
#18 /var/www/common/wikibase-repo/includes/Wiki.php(458): MediaWiki->main()
#19 /var/www/common/wikibase-repo/index.php(55): MediaWiki->run()
#20 {main}

Version: master
Severity: major
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=49264