qapi: type 'info' as Optional[QAPISourceInfo]

For everything typed so far, type this parameter as
Optional[QAPISourceInfo].

In the most generic case, QAPISchemaEntity's info field may be None to
represent types that come from built-in definitions. Although some
Entity types may not currently have any built-in definitions, it is not
easily possible to constrain the type except on an ad-hoc basis using
assertions.

It's easier and simpler, then, to just say it's always an Optional type.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20210201193747.2169670-16-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/commands.py

@@ -296,7 +296,7 @@ def visit_end(self) -> None:
 
     def visit_command(self,
                       name: str,
-                      info: QAPISourceInfo,
+                      info: Optional[QAPISourceInfo],
                       ifcond: List[str],
                       features: List[QAPISchemaFeature],
                       arg_type: Optional[QAPISchemaObjectType],

scripts/qapi/events.py

@@ -213,7 +213,7 @@ def visit_end(self) -> None:
 
     def visit_event(self,
                     name: str,
-                    info: QAPISourceInfo,
+                    info: Optional[QAPISourceInfo],
                     ifcond: List[str],
                     features: List[QAPISchemaFeature],
                     arg_type: Optional[QAPISchemaObjectType],

scripts/qapi/gen.py

@@ -325,7 +325,7 @@ def visit_module(self, name: str) -> None:
             self._add_module(name, self._user_blurb)
             self._begin_user_module(name)
 
-    def visit_include(self, name: str, info: QAPISourceInfo) -> None:
+    def visit_include(self, name: str, info: Optional[QAPISourceInfo]) -> None:
         relname = os.path.relpath(self._module_filename(self._what, name),
                                   os.path.dirname(self._genh.fname))
         self._genh.preamble_add(mcgen('''

scripts/qapi/types.py

@@ -350,7 +350,7 @@ def visit_object_type(self,
 
     def visit_alternate_type(self,
                              name: str,
-                             info: QAPISourceInfo,
+                             info: Optional[QAPISourceInfo],
                              ifcond: List[str],
                              features: List[QAPISchemaFeature],
                              variants: QAPISchemaVariants) -> None:

scripts/qapi/visit.py

@@ -336,7 +336,7 @@ def _begin_user_module(self, name: str) -> None:
 
     def visit_enum_type(self,
                         name: str,
-                        info: QAPISourceInfo,
+                        info: Optional[QAPISourceInfo],
                         ifcond: List[str],
                         features: List[QAPISchemaFeature],
                         members: List[QAPISchemaEnumMember],
@@ -378,7 +378,7 @@ def visit_object_type(self,
 
     def visit_alternate_type(self,
                              name: str,
-                             info: QAPISourceInfo,
+                             info: Optional[QAPISourceInfo],
                              ifcond: List[str],
                              features: List[QAPISchemaFeature],
                              variants: QAPISchemaVariants) -> None: