Re: [PATCH for-6.0 6/6] qapi: Deprecate 'query-kvm'
On Fri, Nov 27, 2020 at 15:53:16 +0000, Daniel Berrange wrote:
On Fri, Nov 27, 2020 at 01:18:09PM +0100, Peter Krempa wrote:
> On Fri, Nov 27, 2020 at 14:45:12 +0300, Roman Bolshakov wrote:
[...]
IIUC, this all relies on us importing a dump of the latest QEMU
capabilities into the libvirt test suite.
Most of the capabilities we import are the release version, but
we also periodically import the git snapshot capabilities and
will refresh them until GA of QEMU.
Could we arrange it so that libvirt only reports an error for use
of deprecated interfaces when testing against the GA capabilities
dump. If testing against QEMU git snapshot capabilities, we can
emit a warning only.
That way, we'll have a grace period in which libvirt can see the
warning from tests, and we would only need to add an override
to silence it once we import the GA capabilities, at which time
it is safe to implement the new solution too.
As I've noted in my reply to Markus, in many cases we develop features
on top of unreleased qemu features. I don't really want to throw a
spanner into that process.
While deprecating old interfaces which are changed would lead to
regression in behaviour rather than releasing a broken feature if
changes are done in the API of a new feature the situation is slightly
worse, but it's also a very rare occurence.
I want to basically just an agreement that after such a thing is done
libvirt will be notified. We'll still try to develop replacements sooner
which can actually catch problems in the new features sooner than they
are released in qemu.