Maksim Davydov <davydov-...@yandex-team.ru> writes: > Thanks for reviewing > Sorry for replying late > > On 12/1/23 12:49, Markus Armbruster wrote: >> I apologize for the lateness of my review. >> >> Maksim Davydov <davydov-...@yandex-team.ru> writes: >> >>> To control that creating new machine type doesn't affect the previous >>> types (their compat_props) and to check complex compat_props inheritance >>> we need qmp command to print machine type compatible properties. >>> >>> This patch adds the ability to get list of all the compat_props of the >>> corresponding supported machines for their comparison via new optional >>> argument of "query-machines" command. >> >> Sounds like this is to let developers prevent unwanted change. Such >> testing interfaces need not and should not be stable interfaces. >> Thoughts? > > I'm not sure that rightly understand your idea about unstable: do you mean > that we can allow this interface to be not robust (e.g. compat-props in > MachineInfo can be not presented) or that this is new thusit can be > unstable?
It's about external interface stability: incompatible change requires deprecation and a grace period. See docs/about/deprecated.rst first section. QMP is a stable external interface, except for parts marked unstable. In my review, I wondered whether the QMP interface you add needs to be stable in that sense. Does it? If no, I'll gladly show you how to mark it unstable. >>> Signed-off-by: Maksim Davydov <davydov-...@yandex-team.ru> >>> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru> [...] >>> diff --git a/qapi/machine.json b/qapi/machine.json >>> index b6d634b30d..8ca0c134a2 100644 >>> --- a/qapi/machine.json >>> +++ b/qapi/machine.json [...] >>> ## >>> # @query-machines: >>> # >>> # Return a list of supported machines >>> # >>> +# @compat-props: if true return will contain information about machine type >>> +# compatible properties (since 8.2) >> >> "compatibility properties" >> >> Suppressing parts of the output makes sense only if it's fairly big. >> How much additional compat-props output do you observe? > > now, there are 61 machines types, so this qmp command generates a 450KB JSON Uff. Recommend to explain this briefly in the commit message. Something like "Since information on compatibility properties can increase the command output by a factor of 40, add an argument to enable it, default off." Does make me wonder whether we want a separate command, though. [...]
