qapi: Check for member name conflicts with a base class

Our type inheritance for both 'struct' and for flat 'union' merges
key/value pairs from the base class with those from the type in
question.  Although the C code currently boxes things so that there
is a distinction between which member is referred to, the QMP wire
format does not allow passing a key more than once in a single
object.  Besides, if we ever change the generated C code to not be
quite so boxy, we'd want to avoid duplicate member names there,
too.

Fix a testsuite entry added in an earlier patch, as well as adding
a couple more tests to ensure we have appropriate coverage.  Ensure
that collisions are detected, regardless of whether there is a
difference in opinion on whether the member name is optional.

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, 6 insertions, 0 deletions

diff --git a/tests/qapi-schema/struct-base-clash.json b/tests/qapi-schema/struct-base-clash.json
new file mode 100644
index 0000000000..f2afc9b6f6
--- /dev/null
+++ b/tests/qapi-schema/struct-base-clash.json
@@ -0,0 +1,6 @@
+# we check for no duplicate keys with base
+{ 'struct': 'Base',
+  'data': { 'name': 'str' } }
+{ 'struct': 'Sub',
+  'base': 'Base',
+  'data': { 'name': 'str' } }