Re: [PATCH v5 19/36] qapi/events.py: add type hint annotations

[Markus Armbruster <armbru@redhat.com>]

John Snow <jsnow@redhat.com> writes:

> Annotations do not change runtime behavior.
> This commit *only* adds annotations.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
> Reviewed-by: Cleber Rosa <crosa@redhat.com>
> ---
>  scripts/qapi/events.py | 46 ++++++++++++++++++++++++++++++++----------
>  scripts/qapi/mypy.ini  |  5 -----
>  2 files changed, 35 insertions(+), 16 deletions(-)
>
> diff --git a/scripts/qapi/events.py b/scripts/qapi/events.py
> index f840a62ed92..57e0939e963 100644
> --- a/scripts/qapi/events.py
> +++ b/scripts/qapi/events.py
> @@ -12,19 +12,31 @@
>  See the COPYING file in the top-level directory.
>  """
>  
> +from typing import List
> +
>  from .common import c_enum_const, c_name, mcgen
>  from .gen import QAPISchemaModularCVisitor, build_params, ifcontext
> -from .schema import QAPISchemaEnumMember
> +from .schema import (
> +    QAPISchema,
> +    QAPISchemaEnumMember,
> +    QAPISchemaFeature,
> +    QAPISchemaObjectType,
> +)
> +from .source import QAPISourceInfo
>  from .types import gen_enum, gen_enum_lookup
>  
>  
> -def build_event_send_proto(name, arg_type, boxed):
> +def build_event_send_proto(name: str,
> +                           arg_type: QAPISchemaObjectType,
> +                           boxed: bool) -> str:
>      return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
>          'c_name': c_name(name.lower()),
>          'param': build_params(arg_type, boxed)}
>  
>  
> -def gen_event_send_decl(name, arg_type, boxed):
> +def gen_event_send_decl(name: str,
> +                        arg_type: QAPISchemaObjectType,
> +                        boxed: bool) -> str:
>      return mcgen('''
>  
>  %(proto)s;
> @@ -33,7 +45,7 @@ def gen_event_send_decl(name, arg_type, boxed):
>  
>  
>  # Declare and initialize an object 'qapi' using parameters from build_params()
> -def gen_param_var(typ):
> +def gen_param_var(typ: QAPISchemaObjectType) -> str:
>      assert not typ.variants
>      ret = mcgen('''
>      %(c_name)s param = {
> @@ -61,7 +73,11 @@ def gen_param_var(typ):
>      return ret
>  
>  
> -def gen_event_send(name, arg_type, boxed, event_enum_name, event_emit):
> +def gen_event_send(name: str,
> +                   arg_type: QAPISchemaObjectType,
> +                   boxed: bool,
> +                   event_enum_name: str,
> +                   event_emit: str) -> str:
>      # FIXME: Our declaration of local variables (and of 'errp' in the
>      # parameter list) can collide with exploded members of the event's
>      # data type passed in as parameters.  If this collision ever hits in
> @@ -137,15 +153,15 @@ def gen_event_send(name, arg_type, boxed, event_enum_name, event_emit):
>  
>  class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
>  
> -    def __init__(self, prefix):
> +    def __init__(self, prefix: str):
>          super().__init__(
>              prefix, 'qapi-events',
>              ' * Schema-defined QAPI/QMP events', None, __doc__)
>          self._event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
> -        self._event_enum_members = []
> +        self._event_enum_members: List[QAPISchemaEnumMember] = []
>          self._event_emit_name = c_name(prefix + 'qapi_event_emit')
>  
> -    def _begin_user_module(self, name):
> +    def _begin_user_module(self, name: str) -> None:
>          events = self._module_basename('qapi-events', name)
>          types = self._module_basename('qapi-types', name)
>          visit = self._module_basename('qapi-visit', name)
> @@ -168,7 +184,7 @@ def _begin_user_module(self, name):
>  ''',
>                               types=types))
>  
> -    def visit_end(self):
> +    def visit_end(self) -> None:

Ignorant question: what's the difference between -> None (like here) and
nothing (like __init__() above?

>          self._add_system_module('emit', ' * QAPI Events emission')
>          self._genc.preamble_add(mcgen('''
>  #include "qemu/osdep.h"
[...]