qemu/tests/qapi-schema/union-max.json

# we reject 'max' branch in a union, for collision with C enum
{ 'union': 'Union',
  'data': { 'max': 'int' } }
qapi: Tighten checking of unions Previous commits demonstrated that the generator had several flaws with less-than-perfect unions: - 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 - 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> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> 2015-05-04 18:05:08 +03:00			`# we reject 'max' branch in a union, for collision with C enum`
qapi: Add some union tests Demonstrate that the qapi generator doesn't deal well with unions that aren't up to par. Later patches will update the expected reseults as the generator is made stricter. A few tests work as planned, but most show poor or missing error messages. Of particular note, qapi-code-gen.txt documents 'base' only for flat unions, but the tests here demonstrate that we currently allow a 'base' to a simple union, although it is exercised only in the testsuite. Later patches will remove this undocumented feature, to give us more flexibility in adding other future extensions to union types. For example, one possible extension is the idea of a type-safe simple enum, where added fields tie the discriminator to a user-defined enum type rather than creating an implicit enum from the names in 'data'. But adding such safety on top of a simple enum with a base type could look ambiguous with a flat enum; besides, the documentation also mentions how any simple union can be represented by an equivalent flat union. So it will be simpler to just outlaw support for something we aren't using. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> 2015-05-04 18:05:05 +03:00			`{ 'union': 'Union',`
			`'data': { 'max': 'int' } }`