Re: [PATCH 0/1] qom: fix setting of qdev array properties

[Peter Maydell]

On Fri, 8 Sept 2023 at 13:22, Kevin Wolf <kwolf@redhat.com> wrote:
>
> Am 08.09.2023 um 11:53 hat Peter Maydell geschrieben:
> > On Fri, 8 Sept 2023 at 10:26, Kevin Wolf <kwolf@redhat.com> wrote:
> > > I have a patch to use QList (i.e. JSON lists) that seems to work for the
> > > rocker case. Now I need to find and update all of those internal
> > > callers. Should grepping for '"len-' find all instances that need to be
> > > changed or are you aware of other ways to access the feature?
> >
> > AFAIK the only way to use the feature is to set the len-foo and
> > then foo[0], foo[1], ... properties, using any of the usual APIs.
> > So git grep '\<len-[^-]' should find them all.
> >
> > If you want a cross-check, the devices that use it are easy
> > to find (search for DEFINE_PROP_ARRAY), and almost all of them
> > picked property names that are easy to grep for.
> >
> > But as Daniel says, if you haven't changed the behaviour for
> > "code sets the properties in the right order" they may not
> > need updating.
>
> I'm replacing the 'len-foo' and 'foo[0]' etc. properties with a single
> 'foo' property that takes a list, so the callers need to be adjusted.
> The devices can stay unchanged, though.
>
> > (I would be happy to see the rather hacky implementation replaced
> > with true support for list properties at the qom/qdev level.
> > But the hack is there because it was simpler :-))
>
> It's not really that hard, but it would probably have been even easier
> if we had just used the list support in the visitor interface from the
> beginning instead of adding this hack. (Though obviously that wouldn't
> have worked for user creatable devices before we added JSON support to
> -device.)

If you'd suggested it back in 2013 I'd have been happy to do
array properties a different way :-)

thanks
-- PMM