simple patch to solve (?) the problem

The newly revamped [[Special:Preferences]] checks if all user preference values are valid, and if not, it resets them to the global defaults.

In case of the 'date' preference, the global default is hardcoded to 'default' (see $wgDefaultUserOptions), however, some languages do not have a date formatting style called 'default' (e.g. cs, hu). In those languages, Special:Preferences dies with an internal error “Global default default is invalid for field date” (see http://cs.wikipedia.org/wiki/Soubor:Vnit%C5%99n%C3%AD_chyba2.jpg).

The global default for date formatting should be language-dependent. However, no big deal, it seems we already have that, we are just not using it. See MessagesXx::$defaultDateFormat.

Therefore, I believe a fix might be as simple as presented in the attachment.

Version: unspecified
Severity: major
URL: http://en.wikipedia.org/wiki/Special:Preferences?uselang=cs

Attached: