[PULL 12/13] qapi: Tweak error messages for missing / conflicting meta-type

[Markus Armbruster]

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210831123809.1107782-12-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 scripts/qapi/expr.py               | 23 +++++++++--------------
 tests/qapi-schema/double-type.err  |  4 +---
 tests/qapi-schema/missing-type.err |  2 +-
 3 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 9e2aa1d43a..ae4437ba08 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -630,20 +630,15 @@ def check_exprs(exprs: List[_JSONObject]) -> 
List[_JSONObject]:
         if 'include' in expr:
             continue
 
-        if 'enum' in expr:
-            meta = 'enum'
-        elif 'union' in expr:
-            meta = 'union'
-        elif 'alternate' in expr:
-            meta = 'alternate'
-        elif 'struct' in expr:
-            meta = 'struct'
-        elif 'command' in expr:
-            meta = 'command'
-        elif 'event' in expr:
-            meta = 'event'
-        else:
-            raise QAPISemError(info, "expression is missing metatype")
+        metas = expr.keys() & {'enum', 'struct', 'union', 'alternate',
+                               'command', 'event'}
+        if len(metas) != 1:
+            raise QAPISemError(
+                info,
+                "expression must have exactly one key"
+                " 'enum', 'struct', 'union', 'alternate',"
+                " 'command', 'event'")
+        meta = metas.pop()
 
         check_name_is_str(expr[meta], info, "'%s'" % meta)
         name = cast(str, expr[meta])
diff --git a/tests/qapi-schema/double-type.err 
b/tests/qapi-schema/double-type.err
index 576e716197..6a1e8a5990 100644
--- a/tests/qapi-schema/double-type.err
+++ b/tests/qapi-schema/double-type.err
@@ -1,3 +1 @@
-double-type.json: In struct 'Bar':
-double-type.json:2: struct has unknown key 'command'
-Valid keys are 'base', 'data', 'features', 'if', 'struct'.
+double-type.json:2: expression must have exactly one key 'enum', 'struct', 
'union', 'alternate', 'command', 'event'
diff --git a/tests/qapi-schema/missing-type.err 
b/tests/qapi-schema/missing-type.err
index 5755386a18..cb39569e49 100644
--- a/tests/qapi-schema/missing-type.err
+++ b/tests/qapi-schema/missing-type.err
@@ -1 +1 @@
-missing-type.json:2: expression is missing metatype
+missing-type.json:2: expression must have exactly one key 'enum', 'struct', 
'union', 'alternate', 'command', 'event'
-- 
2.31.1