John Snow <js...@redhat.com> writes:
> On Tue, Nov 21, 2023, 9:21 AM Markus Armbruster <arm...@redhat.com> wrote:
>
>> John Snow <js...@redhat.com> writes:
>>
>> > This function is a bit hard to type as-is; mypy needs some assertions to
>> > assist with the type narrowing.
>> >
>> > Signed-off-by: John Snow <js...@redhat.com>
>> > ---
>> > scripts/qapi/schema.py | 8 ++++++--
>> > 1 file changed, 6 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
>> > index a1094283828..3308f334872 100644
>> > --- a/scripts/qapi/schema.py
>> > +++ b/scripts/qapi/schema.py
>> > @@ -968,8 +968,12 @@ def lookup_entity(self, name, typ=None):
>> > return None
>> > return ent
>> >
>> > - def lookup_type(self, name):
>> > - return self.lookup_entity(name, QAPISchemaType)
>> > + def lookup_type(self, name: str) -> Optional[QAPISchemaType]:
>>
>> Any particular reason not to delay the type hints until PATCH 16?
>>
>
> I forget. In some cases I did things a little differently so that the type
> checking would pass for each patch in the series, which sometimes required
> some concessions.
>
> Is this one of those cases? Uh, I forget.
>
> If it isn't, its almost certainly the case that I just figured I'd type
> this one function in one place instead of splitting it apart into two
> patches.
>
> I can try to shift the typing later and see what happens if you prefer it
> that way.
Well, you structured the series as "minor code changes to prepare for
type hints", followed by "add type hints". So that's what I expect.
When patches deviate from what I expect, I go "am I missing something?"
Adding type hints along the way could work, too. But let's try to stick
to the plan, and add them all in PATCH 16.
>> > + typ = self.lookup_entity(name, QAPISchemaType)
>> > + if typ is None:
>> > + return None
>> > + assert isinstance(typ, QAPISchemaType)
>> > + return typ
>>
>> Would
>>
>> typ = self.lookup_entity(name, QAPISchemaType)
>> assert isinstance(typ, Optional[QAPISchemaType])
>> return typ
>>
>> work?
>>
>
> I don't *think* so, Optional isn't a runtime construct.
Let me try...
$ python
Python 3.11.5 (main, Aug 28 2023, 00:00:00) [GCC 12.3.1 20230508 (Red Hat
12.3.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from typing import Optional
>>> x=None
>>> isinstance(x, Optional[str])
True
>>>
> We can combine it
> into "assert x is None or isinstance(x, foo)" though - I believe that's
> used elsewhere in the qapi generator.
>> >
>> > def resolve_type(self, name, info, what):
>> > typ = self.lookup_type(name)
>>
>>
