qapi: Tweak error messages for unknown / conflicting 'if' keys

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210831123809.1107782-13-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

scripts/qapi/expr.py

@@ -286,13 +286,12 @@ def _check_if(cond: Union[str, object]) -> None:
             raise QAPISemError(
                 info,
                 "'if' condition of %s must be a string or an object" % source)
+        check_keys(cond, info, "'if' condition of %s" % source, [],
+                   ["all", "any", "not"])
         if len(cond) != 1:
             raise QAPISemError(
                 info,
-                "'if' condition dict of %s must have one key: "
-                "'all', 'any' or 'not'" % source)
-        check_keys(cond, info, "'if' condition", [],
-                   ["all", "any", "not"])
+                "'if' condition of %s has conflicting keys" % source)
 
         oper, operands = next(iter(cond.items()))
         if not operands:

tests/qapi-schema/bad-if-key.err

@@ -1,3 +1,3 @@
 bad-if-key.json: In struct 'TestIfStruct':
-bad-if-key.json:2: 'if' condition has unknown key 'value'
+bad-if-key.json:2: 'if' condition of struct has unknown key 'value'
 Valid keys are 'all', 'any', 'not'.

tests/qapi-schema/bad-if-keys.err

@@ -1,2 +1,2 @@
 bad-if-keys.json: In struct 'TestIfStruct':
-bad-if-keys.json:2: 'if' condition dict of struct must have one key: 'all', 'any' or 'not'
+bad-if-keys.json:2: 'if' condition of struct has conflicting keys

tests/qapi-schema/enum-if-invalid.err

@@ -1,3 +1,3 @@
 enum-if-invalid.json: In enum 'TestIfEnum':
-enum-if-invalid.json:2: 'if' condition has unknown key 'val'
+enum-if-invalid.json:2: 'if' condition of 'data' member 'bar' has unknown key 'val'
 Valid keys are 'all', 'any', 'not'.