The following pages all exist on en.wikipedia.org:

• [[Bird]]
• [[Big]]
• [[Big!]]
• [[Big Ten Conference]]

When querying action=opensearch for:

• "Bir": 0 => "Bird" https://en.wikipedia.org/w/api.php?format=json&action=opensearch&namespace=0&search=Bir [input,["Bird","Birmingham",..]]

• "Bird": 0 => "Bird" https://en.wikipedia.org/w/api.php?format=json&action=opensearch&namespace=0&search=Bird [input,["Bird","BirdLife International",..]]

• "Big": https://en.wikipedia.org/w/api.php?format=json&action=opensearch&namespace=0&search=Big ["Big",["Big Ten Conference","Big band",...]]

• "Big": https://en.wikipedia.org/w/api.php?format=json&action=opensearch&namespace=0&search=Big! ["Big!",["Big Ten Conference","Big band",...]]

In the last two, "Big" and "Big!" are nowhere in the response.

Filing against Wikimedia for now, because this seems related to one of our search backends, not plain MediaWiki core or plain MediaWiki core with Extension:TitleKey installed.

This is currently causing issues in VisualEditor when making a link to a page called "Big", or "Big!" as it will think the page doesn't exist and suggest to make a red link, as, thus far, we've always assumed that if a page by the exact title exists, it should be the first suggestion.

It normalising casing and/or special characters is fine, but shouldn't make it not give an exact match as first result.

Version: unspecified
Severity: major
Whiteboard: cirrus-fixed