tests/qapi-schema: New flat union array branch test case

The new test demonstrates another generator crash.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

tests/Makefile

@@ -237,7 +237,8 @@ check-qapi-schema-y := $(addprefix tests/qapi-schema/, \
 	flat-union-invalid-branch-key.json flat-union-reverse-define.json \
 	flat-union-string-discriminator.json union-base-no-discriminator.json \
 	flat-union-bad-discriminator.json flat-union-bad-base.json \
-	flat-union-base-star.json flat-union-int-branch.json \
+	flat-union-base-star.json \
+	flat-union-array-branch.json flat-union-int-branch.json \
 	flat-union-base-union.json flat-union-branch-clash.json \
 	alternate-nested.json alternate-unknown.json alternate-clash.json \
 	alternate-good.json alternate-base.json alternate-array.json \

tests/qapi-schema/flat-union-array-branch.err

+Traceback (most recent call last):
+  File "tests/qapi-schema/test-qapi.py", line 19, in <module>
+    exprs = parse_schema(sys.argv[1])
+  File "scripts/qapi.py", line 760, in parse_schema
+    return check_exprs(schema.exprs)
+  File "scripts/qapi.py", line 743, in check_exprs
+    check_union(expr, info)
+  File "scripts/qapi.py", line 586, in check_union
+    assert branch_struct
+AssertionError

tests/qapi-schema/flat-union-array-branch.exit

+1

tests/qapi-schema/flat-union-array-branch.json

+# we require flat union branches to be a struct
+{ 'enum': 'TestEnum',
+  'data': [ 'value1', 'value2' ] }
+{ 'struct': 'Base',
+  'data': { 'enum1': 'TestEnum' } }
+{ 'struct': 'TestTypeB',
+  'data': { 'integer': 'int' } }
+{ 'union': 'TestUnion',
+  'base': 'Base',
+  'discriminator': 'enum1',
+  'data': { 'value1': ['TestTypeB'],
+            'value2': 'TestTypeB' } }