default plasma theme and fallback

[Marco Martin]

On Friday 26 June 2009, Aaron J. Seigo wrote:
> On Thursday 25 June 2009, Marco Martin wrote:
> > b)mantain oxygen as "default" and just load air instead of oxygen at kde
> > startup
>
> and how will that work for krunner? kwin? put this in every application
> that should be using the global setting? that doesn't seem like a good
> idea.
>
> it also means we have to keep Oxygen up to date with all items we create
> (otherwise there will be no fallback).
>
> > c)have a fallbackTo=foo entry in themes desktop files making possible for
> > themes to fallback to a desired theme (maybe kinda overkill and what
> > happens when a 3rd party theme falls back to another 3rd party theme? or
> > what happens when a theme falls back to an incomplete theme?)
>
> this probably makes sense, but could be combined with:
>
> d) in Plasma::Theme, make the fallback separate from the default theme.
> this way Oxygen could be the fallback, Air the default. we could also cover
> our bases and have it a cascading list of fallbacks, with Oxygen as the
> first fallback and Air the last so if an element appears in Air (our
> default) that doesn't appear in Oxygen, then we're still good. this will
> also preserve things for widgets that put their widgets in default/ (aka
> "Air")
>
> see attached patch.

looks good, i wonder if we could limit this to themes shipped in runtime, 
specifying one looks quite overkill (would introduce the concept of dependency 
between themes, that could be bad or could be good, just to be tough 
carefully:)
anyways to me looks good and is a thing to be backported, at least part of it


> > soo, if we just make the default as air every time the default theme will
> > change the same pain will repeat, if we keep oxygen  as the fallback
> > theme we are condemned to keep it complete for ever (that sounds sensible
> > anyways) but will be less painful for old themes even if someday another
> > new default theme will be provided...
>
> personally i think that themes that rely on a certain subset of elements in
> the fallback theme remaining consistent are operating on a delusion.
>
> in future, they can use FallbackTheme= if that's what they assume. and we
> need a techbase article on this :)