qapi/commands: assert arg_type is not None

When boxed is True, expr.py asserts that we must have
arguments. Ultimately, this should mean that if boxed is True that
arg_type should be defined. Mypy cannot infer this, and does not support
'stateful' type inference, e.g.:

```
if x:
    assert y is not None

...

if x:
    y.etc()
```

does not work, because mypy does not statefully remember the conditional
assertion in the second block. Help mypy out by creating a new local
that it can track more easily.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20210201193747.2169670-2-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
John Snow 2021-02-01 14:37:32 -05:00 committed by Markus Armbruster
parent 6f0e9c26db
commit ec9697ab3f

View File

@ -126,6 +126,9 @@ def gen_marshal(name: str,
boxed: bool,
ret_type: Optional[QAPISchemaType]) -> str:
have_args = boxed or (arg_type and not arg_type.is_empty())
if have_args:
assert arg_type is not None
arg_type_c_name = arg_type.c_name()
ret = mcgen('''
@ -147,7 +150,7 @@ def gen_marshal(name: str,
ret += mcgen('''
%(c_name)s arg = {0};
''',
c_name=arg_type.c_name())
c_name=arg_type_c_name)
ret += mcgen('''
@ -163,7 +166,7 @@ def gen_marshal(name: str,
ok = visit_check_struct(v, errp);
}
''',
c_arg_type=arg_type.c_name())
c_arg_type=arg_type_c_name)
else:
ret += mcgen('''
ok = visit_check_struct(v, errp);
@ -193,7 +196,7 @@ out:
ret += mcgen('''
visit_type_%(c_arg_type)s_members(v, &arg, NULL);
''',
c_arg_type=arg_type.c_name())
c_arg_type=arg_type_c_name)
ret += mcgen('''
visit_end_struct(v, NULL);