[PATCH v2 00/30] Configurable policy for handling deprecated interfaces

[Markus Armbruster]

Markus Armbruster <armbru at redhat.com> writes:

> Based-on: <20200227144531.24309-1-armbru at redhat.com>
>
> This series extends QMP introspection to cover deprecation.
> Additionally, new option -compat lets you configure what to do when
> deprecated interfaces get used.  This is intended for testing users of
> the management interfaces.  It is experimental.
>
> -compat deprecated-input=<in-policy> configures what to do when
> deprecated input is received.  Available policies:
>
> * accept: Accept deprecated commands and arguments (default)
> * reject: Reject them
> * crash: Crash
>
> -compat deprecated-output=<out-policy> configures what to do when
> deprecated output is sent.  Available output policies:
>
> * accept: Emit deprecated command results and events (default)
> * hide: Suppress them

Missing: hide in output of query-qmp-schema.  I can look into that.

> For now, -compat covers only deprecated syntactic aspects of QMP.  We
> may want to extend it to cover semantic aspects, CLI, and experimental
> features.
>
> PATCH 01-04: Documentation fixes
> PATCH 05-10: Test improvements
> PATCH 11-24: Add feature flags to remaining user-defined types and to
>       	     struct members
> PATCH 25-26: New special feature 'deprecated', visible in
>       	     introspection
> PATCH 27-30: New -compat to set policy for handling stuff marked with
>       	     feature 'deprecated'
>
> Comparison to RFC (24 Oct 2019):
> * Cover arguments and results in addition to commands and events
> * Half-baked "[RFC PATCH 18/19] qapi: Include a warning in the
>   response to a deprecated command" dropped
>
> See also last item of
>     Subject: Minutes of KVM Forum BoF on deprecating stuff
>     Date: Fri, 26 Oct 2018 16:03:51 +0200
>     Message-ID: <87mur0ls8o.fsf at dusky.pond.sub.org>
>     https://lists.nongnu.org/archive/html/qemu-devel/2018-10/msg05828.html