Re: [PATCH 08/12] qapi/schema: make QAPISourceInfo mandatory

[Markus Armbruster]

John Snow <jsnow@redhat.com> writes:

> --
>
> events.py had an info to route, was it by choice that it wasn't before?

See below.

I figure this is intentionally below the -- line, but ...

> Signed-off-by: John Snow <jsnow@redhat.com>

... this should be above it.

> ---
>  scripts/qapi/events.py |  2 +-
>  scripts/qapi/schema.py | 23 +++++++++++++----------
>  scripts/qapi/types.py  |  9 +++++----
>  scripts/qapi/visit.py  |  6 +++---
>  4 files changed, 22 insertions(+), 18 deletions(-)
>
> diff --git a/scripts/qapi/events.py b/scripts/qapi/events.py
> index 9851653b9d11..9ba4f109028d 100644
> --- a/scripts/qapi/events.py
> +++ b/scripts/qapi/events.py
> @@ -225,7 +225,7 @@ def visit_event(self,
>                                            self._event_emit_name))
>          # Note: we generate the enum member regardless of @ifcond, to
>          # keep the enumeration usable in target-independent code.
> -        self._event_enum_members.append(QAPISchemaEnumMember(name, None))
> +        self._event_enum_members.append(QAPISchemaEnumMember(name, info))

We pass None because errors should never happen, and None makes that
quite clear.

We don't actually have a built-in QAPISchemaEnumType for the event enum.
We merely generate a C enum QAPIEvent along with macro QAPIEvent_str(),
by passing self._event_emit_name, self._event_enum_members straight to
gen_enum() and gen_enum_lookup().

If we did build a QAPISchemaEnumType, and used it to diagnose clashes,
then clashes would be reported like

    mumble.json: In event 'A-B':
    mumble.json: 2: value 'A-B' collides with value 'A_B'

leaving you guessing what "value" means, and where 'A_B' may be.

Bug: we don't diagnose certain event name clashes.  I'll fix it.

>  
>  
>  def gen_events(schema: QAPISchema,
> diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
> index 720449feee4d..d5f19732b516 100644
> --- a/scripts/qapi/schema.py
> +++ b/scripts/qapi/schema.py
> @@ -23,6 +23,7 @@
>  from .error import QAPIError, QAPISemError
>  from .expr import check_exprs
>  from .parser import QAPISchemaParser
> +from .source import QAPISourceInfo
>  
>  
>  class QAPISchemaEntity:
> @@ -36,10 +37,10 @@ def __init__(self, name, info, doc, ifcond=None, 
> features=None):
>          self.name = name
>          self._module = None
>          # For explicitly defined entities, info points to the (explicit)
> -        # definition.  For builtins (and their arrays), info is None.
> -        # For implicitly defined entities, info points to a place that
> -        # triggered the implicit definition (there may be more than one
> -        # such place).
> +        # definition.  For builtins (and their arrays), info is a null-object
> +        # sentinel that evaluates to False. For implicitly defined entities,
> +        # info points to a place that triggered the implicit definition
> +        # (there may be more than one such place).

s/builtins/built-in types/

The meaning of "a null object sentinel" is less than clear.  Perhaps "a
special object".

>          self.info = info
>          self.doc = doc
>          self._ifcond = ifcond or []
> @@ -209,7 +210,7 @@ class QAPISchemaBuiltinType(QAPISchemaType):
>      meta = 'built-in'
>  
>      def __init__(self, name, json_type, c_type):
> -        super().__init__(name, None, None)
> +        super().__init__(name, QAPISourceInfo.builtin(), None)
>          assert not c_type or isinstance(c_type, str)
>          assert json_type in ('string', 'number', 'int', 'boolean', 'null',
>                               'value')
> @@ -871,7 +872,7 @@ def resolve_type(self, name, info, what):
>          return typ
>  
>      def _module_name(self, fname):
> -        if fname is None:
> +        if not fname:
>              return None
>          return os.path.relpath(fname, self._schema_dir)
>  

Sure this hunk belongs to this patch?

> @@ -897,9 +898,11 @@ def _def_builtin_type(self, name, json_type, c_type):
>          # be nice, but we can't as long as their generated code
>          # (qapi-builtin-types.[ch]) may be shared by some other
>          # schema.
> -        self._make_array_type(name, None)
> +        self._make_array_type(name, QAPISourceInfo.builtin())
>  
>      def _def_predefineds(self):
> +        info = QAPISourceInfo.builtin()
> +

Everything else gets its very own copy of the "no source info" object,
except for the stuff defined here, which gets to share one.  Isn't that
odd?

>          for t in [('str',    'string',  'char' + POINTER_SUFFIX),
>                    ('number', 'number',  'double'),
>                    ('int',    'int',     'int64_t'),
> @@ -917,15 +920,15 @@ def _def_predefineds(self):
>                    ('null',   'null',    'QNull' + POINTER_SUFFIX)]:
>              self._def_builtin_type(*t)
>          self.the_empty_object_type = QAPISchemaObjectType(
> -            'q_empty', None, None, None, None, None, [], None)
> +            'q_empty', info, None, None, None, None, [], None)
>          self._def_entity(self.the_empty_object_type)
>  
>          qtypes = ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist',
>                    'qbool']
>          qtype_values = self._make_enum_members(
> -            [{'name': n} for n in qtypes], None)
> +            [{'name': n} for n in qtypes], info)
>  
> -        self._def_entity(QAPISchemaEnumType('QType', None, None, None, None,
> +        self._def_entity(QAPISchemaEnumType('QType', info, None, None, None,
>                                              qtype_values, 'QTYPE'))
>  
>      def _make_features(self, features, info):
> diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
> index 2b4916cdaa1b..a3a16284006b 100644
> --- a/scripts/qapi/types.py
> +++ b/scripts/qapi/types.py
> @@ -71,7 +71,8 @@ def gen_enum(name: str,
>               members: List[QAPISchemaEnumMember],
>               prefix: Optional[str] = None) -> str:
>      # append automatically generated _MAX value
> -    enum_members = members + [QAPISchemaEnumMember('_MAX', None)]
> +    enum_members = members + [
> +        QAPISchemaEnumMember('_MAX', QAPISourceInfo.builtin())]
>  
>      ret = mcgen('''
>  
> @@ -306,7 +307,7 @@ def _gen_type_cleanup(self, name: str) -> None:
>  
>      def visit_enum_type(self,
>                          name: str,
> -                        info: Optional[QAPISourceInfo],
> +                        info: QAPISourceInfo,
>                          ifcond: List[str],
>                          features: List[QAPISchemaFeature],
>                          members: List[QAPISchemaEnumMember],
> @@ -317,7 +318,7 @@ def visit_enum_type(self,
>  
>      def visit_array_type(self,
>                           name: str,
> -                         info: Optional[QAPISourceInfo],
> +                         info: QAPISourceInfo,
>                           ifcond: List[str],
>                           element_type: QAPISchemaType) -> None:
>          with ifcontext(ifcond, self._genh, self._genc):
> @@ -327,7 +328,7 @@ def visit_array_type(self,
>  
>      def visit_object_type(self,
>                            name: str,
> -                          info: Optional[QAPISourceInfo],
> +                          info: QAPISourceInfo,
>                            ifcond: List[str],
>                            features: List[QAPISchemaFeature],
>                            base: Optional[QAPISchemaObjectType],
> diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
> index 339f1521524c..3f49c307c566 100644
> --- a/scripts/qapi/visit.py
> +++ b/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],
> @@ -347,7 +347,7 @@ def visit_enum_type(self,
>  
>      def visit_array_type(self,
>                           name: str,
> -                         info: Optional[QAPISourceInfo],
> +                         info: QAPISourceInfo,
>                           ifcond: List[str],
>                           element_type: QAPISchemaType) -> None:
>          with ifcontext(ifcond, self._genh, self._genc):
> @@ -356,7 +356,7 @@ def visit_array_type(self,
>  
>      def visit_object_type(self,
>                            name: str,
> -                          info: Optional[QAPISourceInfo],
> +                          info: QAPISourceInfo,
>                            ifcond: List[str],
>                            features: List[QAPISchemaFeature],
>                            base: Optional[QAPISchemaObjectType],