On Wed, Jun 05, 2013 at 07:57:11PM +0100, Peter Maydell wrote: > On 5 June 2013 19:31, Eduardo Habkost <ehabk...@redhat.com> wrote: > > On Wed, Jun 05, 2013 at 07:29:46PM +0200, Andreas Färber wrote: > >> Am 05.06.2013 19:17, schrieb Eduardo Habkost: > >> > We have had this discussion before, and I remember Anthony saying that > >> > anything set using global properties _must_ be static properties, > >> > period. > >> > >> Obviously I am not aware of that, might that have been an IRC discussion?! > > > > Yeah, it was on IRC (on 2012-10-03). Quoting Anthony: "globals not > > working with non-static properties is a feature, not a bug". > > Did it come with a rationale attached? Seems a bit weird...
Excerpt from the chat: <ehabkost> imammedo2: aliguori: what about moving the current version forward, and convert that to static properties later, as part of the DeviceState work? <ehabkost> because we will need to support global properties only after converting to DeviceState, anyway <aliguori> imammedo, global properties are a qdev-only thing, i don't want to change that <aliguori> ehabkost, i think this has to happen as static properties from the beginnign <aliguori> otherwise we just dig ourselves further into the hole <aliguori> and it's so simple <aliguori> i can't understand why we'd make it harder than it needs to be :-) <ehabkost> aliguori: I don't understand why it has to be so harder, either. we could simply make global properties work with the dynamically-registered properties ;-) <aliguori> ehabkost, problem #1: you can't introspect dynamic properties <aliguori> so if you do that, libvirt can't tell that they're there <aliguori> which means you also have to solve that problem <aliguori> and the approach bonzini and i agreed to on that was: only use static properties when you need to do introspection <ehabkost> aliguori: isn't this just a matter of ordering? we could initialize the list of properties dynamically, but at class_init time <aliguori> not, it has to do with how property introspection works <aliguori> b/c it's class based <aliguori> static properties are tied to classes <aliguori> but dynamic properties have no relationship to the class <aliguori> so there's no obvious way to determine whether a class has a particular property that's dynamic without instantiating an object first <aliguori> it gets a bit hairy <ehabkost> aliguori: I would be happy initializing the list of properties on class_init time <aliguori> that's not possible today <ehabkost> if DeviceClass.props were a list (still initialized by class_init) instead of an array, it would be much easier <aliguori> i've gotta run, but trust me, this rat holes quickly... -- Eduardo
