qapi: Better error messages for bad enums

The previous commit demonstrated that the generator had several
flaws with less-than-perfect enums:
- an enum that listed the same string twice (or two variant
strings that map to the same C enumerator) ended up generating
an invalid C enum
- because the generator adds a _MAX terminator to each enum,
the use of an enum member 'max' can also cause this clash
- if an enum omits 'data', the generator left a python stack
trace rather than a graceful message
- an enum that used a non-array 'data' was silently accepted by
the parser
- an enum that used non-string members in the 'data' member
was silently accepted by the parser

Add check_enum to cover these situations, and update testcases
to match.  While valid .json files won't trigger any of these
cases, we might as well be nicer to developers that make a typo
while trying to add new QAPI code.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/qapi-schema/enum-missing-data.json b/tests/qapi-schema/enum-missing-data.json
index 01f3f32e70..558fd35e93 100644
--- a/tests/qapi-schema/enum-missing-data.json
+++ b/tests/qapi-schema/enum-missing-data.json
@@ -1,2 +1,2 @@
-# FIXME: we should require that all QAPI enums have a data array
+# we require that all QAPI enums have a data array
 { 'enum': 'MyEnum' }