Re: [PATCH 5/5] qom: Make container_get() strict to always walk or return container

[Peter Xu]

On Tue, Nov 19, 2024 at 10:03:22AM +0000, Daniel P. Berrangé wrote:
> The docs are a welcome addition, but at the same time the docs won't get
> read most of the time.
> 
> With this in mind, IMHO, it is a conceptually *terrible* design for us to
> have a method called "get" which magically *creates* stuff as a side-effect
> of its calling. We'd be well served by fixing that design problem.
> 
> If I look in the code at what calls we have to container_get, and more
> specifically what "path" values we pass, there are not actually that many:
> 
>   /objects
>   /chardevs
>   /unattached
>   /machine
>   /peripheral
>   /peripheral-anon
>   /backend
>   /dr-connector
>   
> 
> Ignoring the last one, those other 7 containers are things we expect
> to exist in *every* system emulator.
> 
> Second, every single one of them is a single level deep. IOW, the for()
> loop in container_get is effectively pointless.
> 
> We can fix this by having a single method:
> 
>  void container_create_builtin(Object *root)
> 
> which creates the 7 built-in standard containers we expect
> everywhere, with open coded object_new + add_child calls. 
> 
> Then all current users of container_get() can switch over
> to object_resolve_path, and container_get() can be eliminated.
> 
> The 'dr-connector' creation can just be open-coded using
> object_new() in the spapr code.

Yes I think this could make sense, also after I noticed that the assert I
added may not always work..  Please ignore this series then, I'll prepare
something else soon.

-- 
Peter Xu