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

[Markus Armbruster]

Kevin Wolf <kwolf@redhat.com> writes:

> Am 04.09.2023 um 18:25 hat Daniel P. Berrangé geschrieben:
>> By the time of the 8.2.0 release, it will have been 2 years and 6
>> releases since we accidentally broke setting of array properties
>> for user creatable devices:
>> 
>>   https://gitlab.com/qemu-project/qemu/-/issues/1090
>
> Oh, nice!

Nice?  *Awesome*!

> Well, maybe that sounds a bit wrong, but the syntax that was broken was
> problematic and more of a hack,

A monstrosity, in my opinion.  I tried to strangle it in the crib, but
its guardians wouldn't let me.  Can dig up references for the morbidly
curious.

>                                 and after two years there is clearly no
> need to bring the exact same syntax back now.

Exactly.

> So I'd suggest we bring the funcionality back, but with proper QAPI
> lists instead of len-foo/foo[*].
>
> If we ever want to continue with command line QAPIfication, this change
> would already solve one of the compatibility concerns we've had in the
> past.
>
>> I still think for user creatable devices we'd be better off just
>> mandating the use of JSON syntax for -device and thus leveraging
>> the native JSON array type. This patch was the quick fix for the
>> existing array property syntax though.
>
> I agree, let's not apply this one. It puts another ugly hack in the
> common QOM code path just to bring back the old ugly hack in qdev.

Since -device supports both JSON and dotted keys, we'd still offer a
(differently ugly) solution for users averse to JSON.