Google Code-in

This task is about MediaWiki's core codebase.

One of the errors that people run into when setting up new MediaWiki installations is "Could not open lock file for "mwstore://local-backend/local-public/..." (in English; the message ID is lockmanager-fail-openlock).

That message is unhelpful and should be descriptive/helpful for fixing the problem.

It should be changed to something like this:

"Could not open lock file for "mwstore://local-backend/local-public/...". Make sure your upload directory is configured correctly and your web server has permission to write to that directory. See https://www.mediawiki.org/wiki/Special:MyLanguage/Manual:$wgUploadDirectory for more information."

You are expected to provide a patch in Wikimedia Gerrit. See https://www.mediawiki.org/wiki/Gerrit/Tutorial for how to set up Git and Gerrit.