John Snow <js...@redhat.com> writes: > Declare, but don't initialize the "members" field with type > List[QAPISchemaObjectTypeMember]. > > This simplifies the typing from what would otherwise be > Optional[List[T]] to merely List[T]. This removes the need to add > assertions to several callsites that this value is not None - which it > never will be after the delayed initialization in check() anyway. > > The type declaration without initialization trick will cause accidental > uses of this field prior to full initialization to raise an > AttributeError. > > (Note that it is valid to have an empty members list, see the internal > q_empty object as an example. For this reason, we cannot use the empty > list as a replacement test for full initialization and instead rely on > the _checked/_check_complete fields.) > > Signed-off-by: John Snow <js...@redhat.com> > --- > scripts/qapi/schema.py | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py > index 50ebc4f12de..fb30314741a 100644 > --- a/scripts/qapi/schema.py > +++ b/scripts/qapi/schema.py > @@ -20,7 +20,7 @@ > from collections import OrderedDict > import os > import re > -from typing import List, Optional > +from typing import List, Optional, cast > > from .common import ( > POINTER_SUFFIX, > @@ -449,7 +449,7 @@ def __init__(self, name, info, doc, ifcond, features, > self.base = None > self.local_members = local_members > self.variants = variants > - self.members = None > + self.members: List[QAPISchemaObjectTypeMember] > self._check_complete = False > > def check(self, schema): > @@ -482,7 +482,11 @@ def check(self, schema): > for m in self.local_members: > m.check(schema) > m.check_clash(self.info, seen) > - members = seen.values() > + > + # check_clash works in terms of the supertype, but local_members > + # is asserted to be List[QAPISchemaObjectTypeMember].
Do you mean "but self.members is declared as List[QAPISchemaObjectTypeMember]"? > + # Cast down to the subtype. > + members = cast(List[QAPISchemaObjectTypeMember], list(seen.values())) Let's break the line after the comma. > > if self.variants: > self.variants.check(schema, seen) > @@ -515,11 +519,9 @@ def is_implicit(self): > return self.name.startswith('q_') > > def is_empty(self): > - assert self.members is not None > return not self.members and not self.variants > > def has_conditional_members(self): > - assert self.members is not None > return any(m.ifcond.is_present() for m in self.members) > > def c_name(self):