CirrusSearch insource: not working

CLOSED This issue is closed by nike

I tried to search for insource:Project:Copyright, and got the following error:

[10055add3fc7981b9afb68ee] /w/i.php?search=insource%3A%22Project%3ACopyrights%22&title=Special%3ASearch&fulltext=1 RuntimeException from line 398 of /srv/mediawiki/tags/2016-08-23_08:15:51/extensions/CirrusSearch/includes/Search/ResultsType.php: regex is only supported with $wgCirrusSearchUseExperimentalHighlighter = true
Backtrace:
#0 /srv/mediawiki/tags/2016-08-23_08:15:51/extensions/CirrusSearch/includes/Search/SearchContext.php(430): CirrusSearch\Search\FullTextResultsType->getHighlightingConfiguration(array)
#1 /srv/mediawiki/tags/2016-08-23_08:15:51/extensions/CirrusSearch/includes/Searcher.php(576): CirrusSearch\Search\SearchContext->getHighlight(CirrusSearch\Search\FullTextResultsType)
#2 /srv/mediawiki/tags/2016-08-23_08:15:51/extensions/CirrusSearch/includes/Searcher.php(352): CirrusSearch\Searcher->search(string)
#3 /srv/mediawiki/tags/2016-08-23_08:15:51/extensions/CirrusSearch/includes/CirrusSearch.php(406): CirrusSearch\Searcher->searchText(string, boolean)
#4 /srv/mediawiki/tags/2016-08-23_08:15:51/extensions/CirrusSearch/includes/CirrusSearch.php(150): CirrusSearch->searchTextReal(string, NULL)
#5 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/specials/SpecialSearch.php(298): CirrusSearch->searchText(string)
#6 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/specials/SpecialSearch.php(150): SpecialSearch->showResults(string)
#7 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/specialpage/SpecialPage.php(522): SpecialSearch->execute(NULL)
#8 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/specialpage/SpecialPageFactory.php(583): SpecialPage->run(NULL)
#9 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/MediaWiki.php(283): SpecialPageFactory::executePath(Title, RequestContext)
#10 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/MediaWiki.php(749): MediaWiki->performRequest()
#11 /srv/mediawiki/tags/2016-08-23_08:15:51/includes/MediaWiki.php(521): MediaWiki->main()
#12 /srv/mediawiki/tags/2016-08-23_08:15:51/index.php(43): MediaWiki->run()
#13 {main}

The problems are:

1. The error message isn’t right (it tells regex isn’t supported, altough I searched for a simple text in the source code (I don’t know wheter the error message is right that you should enable $wgCirrusSearchUseExperimentalHighlighter for normal insource search).
2. Why have I got this whole error message? (I.e. in Wikimedia wikis I get a nice error page, and the details, including file paths, are hidden from the Internet.)
3. And last, but not least: why doesn’t this work?

This no longer happens.