[xwiki-devs] [Proposal] "Plug-in" application configuration using objects.

The problem: Each time an xar application is added, if it is to be configured it must alter XWikiPreferences and the administration application making the separation of different applications meaningless. The goal: Ability to install an application from an xar file and have configuration appear on the appropriate administration sheet, also the ability to remove an application easily without leaving anything behind. My proposal: Add a class called XWiki.Configurable, any document which contains an object of this class is pulled into the appropriate administration sheet via an includeForm call. Concerns: Upgradeability - We must be able to save the old configuration when the user does an update. I think this should be up to the individual application to detect that it has been updated, get it's configuration back from the document history and reinstall the old configuration. Security - We can't allow just anyone to create a page which will be pulled into the administration sheet. It must be limited to those with admin or programming rights. The Configurable class: I think it should contain two fields, one telling which administration sheet it should be displayed on and the other holding a version number which is incremented every time an application's configuration changes such that it cannot simply copy the old configuration into the updated application, much like the database is numbered according to the revision number of the last schema change. WDYT? Caleb