On 24 Jun 2016, at 13:25, Martin Kletzander <mkletzan@redhat.com> wrote:
And what about the current bad behavior when you do this?

 virsh attach interface f24 --type network --source default --live
 virsh attach interface f24 --type network --source default --live
--config


This can be separated into two different issues.  If you do
attach-interface, we generate an XML without address, so you should be
able to do the above and have 2 more interfaces live, the second one
would be identical to the only one added to config.

What if we guaranteed that adding a device with both “—live —config” options
at once would always generate the same address? It could even leave some
holes (unassigned addresses) in one of {config, live}, but it doesn’t bother us,
does it? It would make the ABI stable.
If finding such address would be impossible, the user would be informed that
he/she can try adding the device separately using two calls without ABI stability.
This solution means that there are less surprises for the user.
Is there any reason it can’t be done, apart from complicating the code?

Besides, how often do people run —live without —config? Perhaps we should
figure out what the most common use case is, make it work flawlessly
and have some undesired behavior in other cases as a compromise.

Have a nice day,
Tomasz