Re: [Qemu-devel] [PATCH v5 08/28] qapi: Better error messages for bad unions

[Eric Blake <eblake@redhat.com>]

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On 03/24/2015 02:03 PM, Eric Blake wrote:
> Previous commits demonstrated that the generator had several
> flaws with less-than-perfect unions:
> - make the use of a base without discriminator a hard error,
> since the previous patch removed all remaining uses of it
> - a simple union that listed the same branch twice (or two variant
> names that map to the same C enumerator, including the implicit
> MAX sentinel) ended up generating invalid C code
> - checking 'if discriminator' prior to 'if discriminator == {}'

Another commit typo; should read:
 checking 'if not discriminator' prior to 'if discriminator == {}'

> leads to dead code in python, and ended up processing anonymous
> unions as if they were simple unions
> - an anonymous union that listed two branches with the same qtype
> ended up generating invalid C code
> - the generator crashed on anonymous union attempts to use an
> array type
> - the generator was silently ignoring a base type for anonymous
> unions
> - the generator allowed unknown types or nested anonymous unions
> as a branch in an anonymous union
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---


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


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