RFD: Using "Type=MetaApplication" for package managers and application stores

[Jacob Edwards]

Hello everyone.

Over the past few years Ubuntu has been using desktop entries to fetch
applications from its repositories and display them in the software
center. All packages with a desktop file are considered applications;
they appear with their entries' Name, Icon, and Comment in the
software center, while other packages are hidden as "technical items".

It turns out this approach is problematic.

 * Some applications have extra desktop launchers. Wesnoth, for instance,
   comes with a map editor. From the perspective of an app store, however,
   'wesnoth.desktop' and 'wesnoth-1.8_editor.desktop' are just one app.
 * Some applications have no primary launcher. Wine, for instance, comes
   with a notepad, a configuration launcher, a registry editor, a program
   uninstaller, a help app, and a drive browser. None of these embody
   "Wine" as one thing a user is interested in installing.
 * Finally, at a package level, it is often advantageous to package
   desktop launchers separately from the main package. So an app store
   ends up installing a 'app-common' package instead of the entire
   application.

In the past we've manually maintained an entry blacklist and package->app
mapping for the software center. It's become clear that this solution
won't scale.

There's been some discussion around a solution at the package level:

# https://dev.launchpad.net/ArchiveIndex#Overrides

However, I think it would be much cleaner to extend the Desktop Entry
standard to include *generic, non-executable descriptions of a user
application*. Such a file might look like this:

    [Desktop Entry]
    Version=1.0
    Type=MetaApplication
    Name=Foo Viewer
    Comment=The best viewer for Foo objects available!
    URL=http://fooview.com
    Icon=fooview
    MimeType=image/x-foo;

    # And perhaps.....
    Package=fooview
    Screenshot=http://fooview.com/screenshot.jpg
    Description=[Longer description of fooview here]

Would any other parties be interested in modifications like this landing
in the Desktop Entry spec?