Currently, qdev_get_machine() has a slight misuse on container_get(), as
the helper says "get a container" but in reality the goal is to get the
machine object.  It is still a "container" but not strictly.

Note that it _may_ get a container (at "/machine") in our current unit test
of test-qdev-global-props.c before all these changes, but it's probably
unexpected and worked by accident.

Switch to an explicit object_resolve_path_component(), with a side benefit
that qdev_get_machine() can happen a lot, and we don't need to split the
string ("/machine") every time.  This also paves way for making the helper
container_get() never try to return a non-container at all.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/core/qdev.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 5f13111b77..b622be15ee 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -817,7 +817,12 @@ Object *qdev_get_machine(void)
     static Object *dev;
 
     if (dev == NULL) {
-        dev = container_get(object_get_root(), "/machine");
+        dev = object_resolve_path_component(object_get_root(), "machine");
+        /*
+         * Any call to this function before machine is created is treated
+         * as a programming error as of now.
+         */
+        assert(dev);
     }
 
     return dev;
-- 
2.45.0

On 21/11/24 20:21, Peter Xu wrote:
> Currently, qdev_get_machine() has a slight misuse on container_get(), as
> the helper says "get a container" but in reality the goal is to get the
> machine object.  It is still a "container" but not strictly.
> 
> Note that it _may_ get a container (at "/machine") in our current unit test
> of test-qdev-global-props.c before all these changes, but it's probably
> unexpected and worked by accident.
> 
> Switch to an explicit object_resolve_path_component(), with a side benefit
> that qdev_get_machine() can happen a lot, and we don't need to split the
> string ("/machine") every time.  This also paves way for making the helper
> container_get() never try to return a non-container at all.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>   hw/core/qdev.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>