Link: search for bookmarklet
Other searches do not end up with exceptions. They either produce a page of results or, in the case of too broad a search, a database timeout.
The error in the log is:
Wikimedia\Assert\PreconditionException: Precondition failed: This Title instance does not represent a proper page, but merely a link target.
Software version
MW version: 1.39.2 (626d2da)
Other information
The trace from the exception is:
Wikimedia\Assert\PreconditionException: Precondition failed: This Title instance does not represent a proper page, but merely a link target.
#0 .../includes/Title.php(4190): Wikimedia\Assert\Assert::precondition()
#1 .../includes/Title.php(4171): Title->assertProperPage()
#2 .../includes/Revision/RevisionStore.php(1828): Title->getId()
#3 .../includes/Revision/RevisionStore.php(1733): MediaWiki\Revision\RevisionStore->ensureRevisionRowMatchesPage()
#4 .../includes/Revision/RevisionStore.php(1609): MediaWiki\Revision\RevisionStore->newRevisionFromRowAndSlots()
#5 .../includes/Revision/RevisionStore.php(2348): MediaWiki\Revision\RevisionStore->newRevisionFromRow()
#6 .../includes/Revision/RevisionStore.php(1286): MediaWiki\Revision\RevisionStore->loadRevisionFromConds()
#7 .../includes/search/RevisionSearchResultTrait.php(52): MediaWiki\Revision\RevisionStore->getRevisionByTitle()
#8 .../includes/search/RevisionSearchResult.php(16): RevisionSearchResult->initFromTitle()
#9 .../includes/search/SqlSearchResult.php(36): RevisionSearchResult->__construct()
#10 .../includes/search/SqlSearchResultSet.php(60): SqlSearchResult->__construct()
#11 .../includes/search/SearchResultSet.php(73): SqlSearchResultSet->extractResults()
#12 .../includes/search/SearchResultSet.php(184): SearchResultSet->count()
#13 .../includes/search/SearchEngine.php(201): SearchResultSet->shrink()
#14 .../includes/search/SearchEngine.php(157): SearchEngine->maybePaginate()
#15 .../includes/specials/SpecialSearch.php(447): SearchEngine->searchTitle()
#16 .../includes/specials/SpecialSearch.php(229): SpecialSearch->showResults()
#17 .../includes/specialpage/SpecialPage.php(701): SpecialSearch->execute()
#18 .../includes/specialpage/SpecialPageFactory.php(1428): SpecialPage->run()
#19 .../includes/MediaWiki.php(316): MediaWiki\SpecialPage\SpecialPageFactory->executePath()
#20 .../includes/MediaWiki.php(904): MediaWiki->performRequest()
#21 .../includes/MediaWiki.php(562): MediaWiki->main()
#22 .../index.php(50): MediaWiki->run()
#23 .../index.php(46): wfIndexMain()
#24 {main}