Re: [Qemu-devel] [PATCH v10 23/30] qapi: Check for qapi collisions of flat union branches

[Eric Blake]

On 11/09/2015 10:16 PM, Eric Blake wrote:

>> We have tests covering attempts to do the former
>> (struct-cycle-direct.json, struct-cycle-indirect.json).  As far as I can
>> see, we don't have tests covering the latter.  Do we catch it?
> 
> Yes, at least by virtue of the ad hoc tests: attempting to reuse a base
> type of the flat union as a variant member will cause the qapi members
> of the base type to appear more than once in the JSON object (that is,
> the checks that reject flat-union-clash-member.json would also reject
> this scenario). To test:
> 
> diff --git i/tests/qapi-schema/qapi-schema-test.json
> w/tests/qapi-schema/qapi-schema-test.json
> index 44638da..16b2ffb 100644
> --- i/tests/qapi-schema/qapi-schema-test.json
> +++ w/tests/qapi-schema/qapi-schema-test.json
> @@ -67,7 +67,7 @@
>    'discriminator': 'enum1',
>    'data': { 'value1' : 'UserDefA',
>              'value2' : 'UserDefB',
> -            'value3' : 'UserDefB' } }
> +            'value3' : 'UserDefUnionBase' } }

Another test I just tried is creating a flat union with:

empty -> base -> union

then use empty as one of the union branches.  In that case, there is no
conflict (although base is included twice, neither inclusion adds
members to the JSON object; and the inclusion is not circular so things
compile just fine).  So probably not worth adding a test for it.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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