tree c921a94149a400671a45fb6c203f9010197383e7
parent 2418d1c43add3e8e7089a092574da703c15ac14c
author John Snow <jsnow@redhat.com> 1710516162 +0100
committer Markus Armbruster <armbru@redhat.com> 1713945834 +0200

qapi/schema: declare type for QAPISchemaObjectTypeMember.type

A QAPISchemaObjectTypeMember's type gets resolved only during .check().
We have QAPISchemaObjectTypeMember.__init__() initialize self.type =
None, and .check() assign the actual type.  Using .type before .check()
is wrong, and hopefully crashes due to the value being None.  Works.

However, it makes for awkward typing.  With .type:
Optional[QAPISchemaType], mypy is of course unable to see that it's None
before .check(), and a QAPISchemaType after.  To help it over the hump,
we'd have to assert self.type is not None before all the (valid) uses.
The assertion catches invalid uses, but only at run time; mypy can't
flag them.

Instead, declare .type in .__init__() as QAPISchemaType *without*
initializing it.  Using .type before .check() now certainly crashes,
which is an improvement.  Mypy still can't flag invalid uses, but that's
okay.

Addresses typing errors such as these:

qapi/schema.py:657: error: "None" has no attribute "alternate_qtype"  [attr-defined]
qapi/schema.py:662: error: "None" has no attribute "describe"  [attr-defined]

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: <20240315152301.3621858-7-armbru@redhat.com>