qemu/tests/qapi-schema/union-optional-branch.json

# union branches cannot be optional
{ 'union': 'Union', 'data': { '*a': 'int', 'b': 'str' } }
qapi: Require valid names Previous commits demonstrated that the generator overlooked various bad naming situations: - types, commands, and events need a valid name - enum members must be valid names, when combined with prefix - union and alternate branches cannot be marked optional Valid upstream names match [a-zA-Z][a-zA-Z0-9_-]; valid downstream names match __[a-zA-Z][a-zA-Z0-9._-]. Enumerations match the weaker [a-zA-Z0-9._-]+ (in part thanks to QKeyCode picking an enum that starts with a digit, which we can't change now due to backwards compatibility). Rather than call out three separate regex, this patch just uses a broader combination that allows both upstream and downstream names, as well as a small hack that realizes that any enum name is merely a suffix to an already valid name prefix (that is, any enum name is valid if prepending _ fits the normal rules). We could reject new enumeration names beginning with a digit by whitelisting existing exceptions. We could also be stricter about the distinction between upstream names (no leading underscore, no use of dot) and downstream (mandatory leading double underscore), but it is probably not worth the bother. 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 18:05:22 +03:00			`# union branches cannot be optional`
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': { '*a': 'int', 'b': 'str' } }`