Re: [PATCH for-6.0 6/6] qapi: Deprecate 'query-kvm'

On Fri, Nov 27, 2020 at 16:44:05 +0100, Markus Armbruster wrote: [...] Oh, yes. That's basically the same thing. The thing is that changes to the new interface are very rare, but very real. Since I don't really want to increase the burden for any normal scenario. I'd also very much like to keep libvirt pulling in snapshots of qemu's capabilities/qapi schema etc throughout the development cycle. It allows us to adapt faster and develop features simultaneously. This unfortunately undermines my own arguments partially as libvirt regularly develops features on top of unreleased qemu features so we are regularly risking very similar circumstances. The small but important difference though is, that releasing a broken feature is not as bad as breaking an existing feature. As a conclusion of the above I'd basically prefer a sort of gentleman's agreement, that new APIs become 'somewhat' stable at the moment the commit deprecating the old interface hits upstream. The 'somewhat'-stable API would mean that any changes to the new API should be consulted with libvirt so that we can either give a go-ahead that we didn't adapt yet, disable the adaptation until the changes can be done, or another compromise depending on what's the state. I know it's hard to enforce, but probably the cheapest in terms of drawbacks any other solution would be. I'll probably keep notifying patchsets which implement and deprecate old api at the same time to keep in mind that we need to be kept in touch, but I really don't want to impose any kind of extra process to development on either side.