On 10/13/2015 12:43 PM, Markus Armbruster wrote:
> Eric Blake <ebl...@redhat.com> writes:
>
>> Rename alternate-clash to alternate-clash-members, and add a
>> new test alternate-clash-type. While similar to the earlier
>> addition of union-clash-type, we have one major difference: a
>> future patch will be simplifying alternates to not need an
>> implict AlternateKind enum, but we still need to detect the
>> collision with the resulting C 'qtype_code type;' tag.
>
> You're alluding to a future change of the generated code from
>
> struct BlockdevRef {
> BlockdevRefKind kind;
> union { /* union tag is @kind */
> void *data;
> BlockdevOptions *definition;
> char *reference;
> };
> };
>
> to
>
> struct BlockdevRef {
> qtype_code type;
> union { /* union tag is @type */
> void *data;
> BlockdevOptions *definition; /* QTYPE_QDICT */
> char *reference; /* QTYPE_QSTRING */
> };
> };
>
> right?Yes. > > I don't think that affects collision checking at all. Both before and > after, we have a tag member, and we need to check for collisions with > its name. I guess I wrote that at one point where I was using alternate.variants.tag_member = None for alternates; but in the meantime, I've reworked things to just use a special subclass of QAPISchemaObjectTypeMember instead, at which point normal collision checking still works. So yeah, I can probably simplify or drop wording here. >> +++ b/tests/qapi-schema/alternate-clash-type.json >> @@ -0,0 +1,10 @@ >> +# Alternate branch 'type' >> +# Reject this, because we would have a clash in generated C, between the >> +# alternate's implicit tag member 'kind' and the branch name 'kind' >> +# within the alternate. >> +# TODO: Even if alternates are simplified in the future to use a simpler >> +# 'qtype_code type' tag, rather than a full QAPISchemaObjectTypeMember, >> +# we must still flag the collision, or else munge the generated C branch >> +# names to allow compilation. > > I don't think there's a TODO here. Again, probably leftover text from my first implementation. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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