Steps to reproduce:
- Load https://www.mediawiki.org/wiki/Special:Upload.
- Select input field //Destination filename://.
- Insert a space character.
- Press tab.
Actual result:
- The spinner does not stop.
- In the JavaScript console the error TypeError: result.query is undefined occurs.
The API request https://www.mediawiki.org/w/api.php?action=query&format=json&formatversion=2&titles=%20&prop=imageinfo&iiprop=uploadwarning returns
{"batchcomplete":true}
The expected key query is missing in the response.