[Special:Preferences] [PHP] Add skin version user preference and configs


[Special:Preferences] [PHP] Add skin version user preference and configs

Add a Vector-specific user preference to Special:Preferences for
toggling skin version, either Legacy Vector or the latest Vector.

The presentation of the new preference section and the default values
for anonymous, new, and existing accounts are configurable via
$wgVectorShowSkinPreferences, $wgVectorDefaultSkinVersion (to be used by
the feature manager in T244481),
$wgVectorDefaultSkinVersionForExistingAccounts, and
$wgVectorDefaultSkinVersionForNewAccounts. These configurations default
to the fullest experience so that third-party configuration is minimal.
See skin.json for details. The configurations are each tested in

When presentation is enabled, the new preference appears as a checkbox;
enabled is Legacy mode and disable is latest. There are a number of
unfortunate details:

  • Showing and hiding a checkbox is supported by OOUI. Showing and hiding a whole section (Vector skin preferences, in this case) is not so this additional client JavaScript functionality is added in Core (see Iaf68b238a8ac7a4fb22b9ef5d6c5a3394ee2e377).
  • Stylization as a checkbox is wanted. However, the implied storage type for OOUI checkboxes is a boolean. This is not wanted in the event that another skin version is added (e.g., '3' or 'alpha'). As a workaround, the preference is converted from a boolean to a version string ('1' or '2') on save in Hooks::onPreferencesFormPreSave() and from a version string to a checkbox enable / disable string ('1' or '0') in onGetPreferences(). There a number of test cases to help cover these concerning details.

Documentation for overriding the skin version as a URL query parameter
is provided in anticipation of T244481.

Bug: T242381
Bug: T245793
Depends-On: Iaf68b238a8ac7a4fb22b9ef5d6c5a3394ee2e377
Depends-On: Ifc2863fca9cd9efd11ac30c780420e8d89e8cb22
Change-Id: I177dad88fc982170641059b6a4f53fbb38eefad6


NiedzielskiAuthored on Jan 23 2020, 9:53 PM
rSVEC4819772ac59a: Bump required MediaWiki version