qapi/schema: add _check_complete flag

Instead of using the None value for the members field, use a dedicated
flag to detect recursive misconfigurations.

This is intended to assist with subsequent patches that seek to remove
the "None" value from the members field (which can never hold that value
after the final call to check()) in order to simplify the static typing
of that field; avoiding the need of assertions littered at many
callsites to eliminate the possibility of the None value.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240315152301.3621858-16-armbru@redhat.com>

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 173e27d9e21d3ba56ae4e8d869d834f85b1b1cf1..2c3de72ae6b072a526498b289420a1c72adcf838 100644 (file)
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -450,12 +450,13 @@ class QAPISchemaObjectType(QAPISchemaType):
         self.local_members = local_members
         self.variants = variants
         self.members = None
+        self._check_complete = False
 
     def check(self, schema):
         # This calls another type T's .check() exactly when the C
         # struct emitted by gen_object() contains that T's C struct
         # (pointers don't count).
-        if self.members is not None:
+        if self._check_complete:
             # A previous .check() completed: nothing to do
             return
         if self._checked:
@@ -464,7 +465,7 @@ class QAPISchemaObjectType(QAPISchemaType):
                                "object %s contains itself" % self.name)
 
         super().check(schema)
-        assert self._checked and self.members is None
+        assert self._checked and not self._check_complete
 
         seen = OrderedDict()
         if self._base_name:
@@ -487,7 +488,8 @@ class QAPISchemaObjectType(QAPISchemaType):
             self.variants.check(schema, seen)
             self.variants.check_clash(self.info, seen)
 
-        self.members = members  # mark completed
+        self.members = members
+        self._check_complete = True  # mark completed
 
     # Check that the members of this type do not cause duplicate JSON members,
     # and update seen to track the members seen so far. Report any errors