As a wiki administrator, I want to be able to install Wikibase on an existing wiki without disturbing its current users.
Wikibase unconditionally overrides MediaWiki’s standard search box with a custom search box that only searches items. That’s fine for Wikidata, and for other wikis where the Wikibase repository is the main functionality, but it’s a problem if there’s also other interesting stuff on the wiki, as on the OpenStreetMap wiki where @Yurik recently set up Wikibase.
* There is an option to disable the custom search box and leave the standard search box in place.
This is a super ugly hack, but it works, at least on my local wiki:
// add this after the Wikibase extension is loaded
$wgResourceModules['wikibase.ui.entitysearch']['scripts'] = ;
However, this may not be possible in more complicated setups, depending on how settings are loaded there.
The search box is implemented in the `wikibase.ui.entitysearch` ResourceLoader module, which is added to output pages in the `RepoHooks::onBeforePageDisplay` function. Presumably it shouldn’t be too difficult to make that hook handler check for a config variable.