Re: [PATCH 03/22] qapi: Convert simple union KeyValue to flat one

[Eric Blake]

On Mon, Sep 13, 2021 at 02:39:13PM +0200, Markus Armbruster wrote:
> Simple unions predate flat unions.  Having both complicates the QAPI
> schema language and the QAPI generator.  We haven't been using simple
> unions in new code for a long time, because they are less flexible and
> somewhat awkward on the wire.
> 
> To prepare for their removal, convert simple union KeyValue to an
> equivalent flat one.  Adds some boilerplate to the schema, which is a
> bit ugly, but a lot easier to maintain than the simple union feature.
> 
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  qapi/ui.json | 30 ++++++++++++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/qapi/ui.json b/qapi/ui.json
> index b2cf7a6759..a6b0dce876 100644
> --- a/qapi/ui.json
> +++ b/qapi/ui.json
> @@ -824,6 +824,30 @@
>              'ac_home', 'ac_back', 'ac_forward', 'ac_refresh', 'ac_bookmarks',
>              'lang1', 'lang2' ] }
>  
> +##
> +# @KeyValueKind:
> +#
> +# Since: 6.1

6.2 now?  Or should this be...

> +
>  ##
>  # @KeyValue:
>  #
> @@ -832,9 +856,11 @@
>  # Since: 1.3

...1.3, since the type has been around by that name already (albeit
implicitly) since that older release?

>  ##
>  { 'union': 'KeyValue',
> +  'base': { 'type': 'KeyValueKind' },
> +  'discriminator': 'type',
>    'data': {
> -    'number': 'int',
> -    'qcode': 'QKeyCode' } }
> +    'number': 'IntWrapper',
> +    'qcode': 'QKeyCodeWrapper' } }
>

I'll trust your decision on the documentation issue; the conversion
itself is sane, so I'm fine with:

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

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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