[PATCH v2 1/5] qapi: Enable enum member introspection to show more than name

Eric Blake eblake at redhat.com
Mon Oct 11 18:37:55 UTC 2021


On Sat, Oct 09, 2021 at 02:09:40PM +0200, Markus Armbruster wrote:
> The next commit will add feature flags to enum members.  There's a
> problem, though: query-qmp-schema shows an enum type's members as an
> array of member names (SchemaInfoEnum member @values).  If it showed
> an array of objects with a name member, we could simply add more
> members to these objects.  Since it's just strings, we can't.
> 
> I can see three ways to correct this design mistake:
> 
> 1. Do it the way we should have done it, plus compatibility goo.
...
> 2. Like 1, but omit "boring" elements of @member, and empty @member.

> 3. Versioned query-qmp-schema.

> This commit implements 1.  Libvirt developers prefer it.
> 
> Signed-off-by: Markus Armbruster <armbru at redhat.com>
> ---
>  qapi/introspect.json       | 21 +++++++++++++++++++--
>  scripts/qapi/introspect.py | 18 ++++++++++++++----
>  2 files changed, 33 insertions(+), 6 deletions(-)

Reviewed-by: Eric Blake <eblake at redhat.com>

> 
> diff --git a/qapi/introspect.json b/qapi/introspect.json
> index 39bd303778..f806bd7281 100644
> --- a/qapi/introspect.json
> +++ b/qapi/introspect.json
> @@ -142,14 +142,31 @@
>  #
>  # Additional SchemaInfo members for meta-type 'enum'.
>  #
> -# @values: the enumeration type's values, in no particular order.
> +# @members: the enum type's members, in no particular order
> +#           (since 6.2).
> +#
> +# @values: the enumeration type's member names, in no particular order.
> +#          Redundant with @members.  Just for backward compatibility.
>  #
>  # Values of this type are JSON string on the wire.
>  #
>  # Since: 2.5
>  ##
>  { 'struct': 'SchemaInfoEnum',
> -  'data': { 'values': ['str'] } }
> +  'data': { 'members': [ 'SchemaInfoEnumMember' ],
> +            'values': ['str'] } }

Not deprecated at this time, I agree with your choice to make the
actual deprecation of 'values' to be in a later patch (if at all).

> +
> +##
> +# @SchemaInfoEnumMember:
> +#
> +# An object member.
> +#
> +# @name: the member's name, as defined in the QAPI schema.
> +#
> +# Since: 6.2
> +##
> +{ 'struct': 'SchemaInfoEnumMember',
> +  'data': { 'name': 'str' } }

Reviewed-by: Eric Blake <eblake at redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org




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