[Qbs] Understanding installation rules

[Richard Weickelt]

> The reason why I added the "application" tag to the rule is that this
> seemed to force the execution of the rule, with otherwise wouldn't be
> considered.

This is semantically wrong because your rule does not produce an
"application" artifact. I'd suggest to add "desktopfile" to the
additionalProductTypes property of your module:

https://doc.qt.io/qbs/qml-qbslanguageitems-module.html#additionalProductTypes-prop

> I understand that QBS is not running the rule again, because both the
> application and the desktopfile are still available under the build
> directory. But why isn't the desktopfile copied to the installRoot
> again, along with the application?

Does it work with the change suggested above?