[PATCH v3 09/20] qapi/schema: assert resolve_type has 'info' and 'what' args on error

[John Snow <jsnow@redhat.com>]

resolve_type() is generally used to resolve configuration-provided type
names into type objects, and generally requires valid 'info' and 'what'
parameters.

In some cases, such as with QAPISchemaArrayType.check(), resolve_type
may be used to resolve built-in types and as such will not have an
'info' argument, but also must not fail in this scenario.

Use an assertion to sate mypy that we will indeed have 'info' and 'what'
parameters for the error pathway in resolve_type.

Note: there are only three callsites to resolve_type at present where
"info" is perceived to be possibly None:

    1) QAPISchemaArrayType.check()
    2) QAPISchemaObjectTypeMember.check()
    3) QAPISchemaEvent.check()

    Of those three, only the first actually ever passes None; the other two
    are limited by their base class initializers which accept info=None, but
    neither subclass actually use a None value in practice, currently.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 scripts/qapi/schema.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index e617abb03af..573be7275a6 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -1004,6 +1004,7 @@ def lookup_type(self, name):
     def resolve_type(self, name, info, what):
         typ = self.lookup_type(name)
         if not typ:
+            assert info and what  # built-in types must not fail lookup
             if callable(what):
                 what = what(info)
             raise QAPISemError(
-- 
2.43.0