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

[Daniel P . Berrangé]

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

Some context:

* Initial identification / report on the mailing list

   https://lists.gnu.org/archive/html/qemu-devel/2022-07/msg00111.html

* Sub-thread of that exploring the background on need/use of array
  properties:

   https://lists.gnu.org/archive/html/qemu-devel/2022-07/msg01531.html

* Markus' initial PoC for an order preserving QDict impl

   https://lists.gnu.org/archive/html/qemu-devel/2022-07/msg00758.html

* A later (unrelated?) patch for order preserving QDict impl

   https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg03229.html

* A re-posting of the new patch

   https://lists.gnu.org/archive/html/qemu-devel/2023-09/msg00292.html

Personally I'm not a fan of the introducing the order preserving QDict
impl, because I feel that the need to preserve QDict ordering is a
design bug. Not that I think the current ordering when iterating over
QDict is in any way special. I just rather see the ordering left as
"undefined" and any callers that need a specific ordering should apply
what they need.

Since setting device array properties requires that 'len-XXX' be
processed first, so the following patch does exactly that. We iterate
over the properties twice, first setting the 'len-XXX' properties,
then setting everything else.

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.

Daniel P. Berrangé (1):
  qom: fix setting of array properties

 qom/object_interfaces.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

-- 
2.41.0