Daniel P. Berrangé <berra...@redhat.com> writes:
> On Thu, Nov 14, 2024 at 01:48:28PM +0100, Markus Armbruster wrote:
>> Daniel P. Berrangé <berra...@redhat.com> writes:
>>
>> > This replaces use of the constants from the QapiSpecialFeatures
>> > enum, with constants from the auto-generate QapiFeatures enum
>> > in qapi-features.h
>> >
>> > The 'deprecated' and 'unstable' features still have a little bit of
>> > special handling, being force defined to be the 1st + 2nd features
>> > in the enum, regardless of whether they're used in the schema. This
>> > retains compatibility with common code that references the features
>> > via the QapiSpecialFeatures constants.
>> >
>> > Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
>> > ---
>> > meson.build | 1 +
>> > scripts/qapi/commands.py | 1 +
>> > scripts/qapi/features.py | 62 ++++++++++++++++++++++++++++++++++++++++
>> > scripts/qapi/gen.py | 4 +--
>> > scripts/qapi/main.py | 2 ++
>> > scripts/qapi/schema.py | 19 +++++++++++-
>> > scripts/qapi/types.py | 6 ++--
>> > scripts/qapi/visit.py | 3 +-
>> > 8 files changed, 92 insertions(+), 6 deletions(-)
>> > create mode 100644 scripts/qapi/features.py
>> >
>> > diff --git a/meson.build b/meson.build
>> > index d26690ce20..b9d58be66f 100644
>> > --- a/meson.build
>> > +++ b/meson.build
>> > @@ -3332,6 +3332,7 @@ qapi_gen_depends = [ meson.current_source_dir() /
>> > 'scripts/qapi/__init__.py',
>> > meson.current_source_dir() /
>> > 'scripts/qapi/schema.py',
>> > meson.current_source_dir() /
>> > 'scripts/qapi/source.py',
>> > meson.current_source_dir() / 'scripts/qapi/types.py',
>> > + meson.current_source_dir() /
>> > 'scripts/qapi/features.py',
>> > meson.current_source_dir() / 'scripts/qapi/visit.py',
>> > meson.current_source_dir() / 'scripts/qapi-gen.py'
>> > ]
>> > diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
>> > index d629d2d97e..bf88bfc442 100644
>> > --- a/scripts/qapi/commands.py
>> > +++ b/scripts/qapi/commands.py
>> > @@ -355,6 +355,7 @@ def visit_begin(self, schema: QAPISchema) -> None:
>> > #include "qemu/osdep.h"
>> > #include "%(prefix)sqapi-commands.h"
>> > #include "%(prefix)sqapi-init-commands.h"
>> > +#include "%(prefix)sqapi-features.h"
>> >
>> > void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
>> > {
>> > diff --git a/scripts/qapi/features.py b/scripts/qapi/features.py
>> > new file mode 100644
>> > index 0000000000..dc10c7cea0
>> > --- /dev/null
>> > +++ b/scripts/qapi/features.py
>> > @@ -0,0 +1,62 @@
>> > +"""
>> > +QAPI types generator
>>
>> QAPI features generator
>>
>> > +
>> > +Copyright 2024 Red Hat
>> > +
>> > +This work is licensed under the terms of the GNU GPL, version 2.
>> > +# See the COPYING file in the top-level directory.
>> > +"""
>> > +
>> > +from typing import List, Optional
>>
>> pylint gripes
>
> Sigh, I really wish we had pylint/mypy/pycodestyle being run as
> part of 'make check' by default. I don't like making the mistake
> of sending patches which fail extra non-default checks maintainers
> need compliance with.
We've made some progress towards running these checkers, but we're not
there, yet.
>> scripts/qapi/features.py:10:0: W0611: Unused List imported from typing
>> (unused-
>> import)
>> scripts/qapi/features.py:10:0: W0611: Unused Optional imported from
>> typing (unused-import)
>>
>> > +
>> > +from .common import c_enum_const, mcgen, c_name
>>
>> scripts/qapi/features.py:12:0: W0611: Unused mcgen imported from common
>> (unused-import)
>>
>> > +from .gen import QAPISchemaMonolithicCVisitor
>> > +from .schema import (
>> > + QAPISchema,
>> > + QAPISchemaFeature,
>> > +)
>> > +from .source import QAPISourceInfo
>>
>> scripts/qapi/features.py:18:0: W0611: Unused QAPISourceInfo imported
>> from source (unused-import)
>>
>> > +
>> > +
>> > +class QAPISchemaGenFeatureVisitor(QAPISchemaMonolithicCVisitor):
>> > +
>> > + def __init__(self, prefix: str):
>> > + super().__init__(
>> > + prefix, 'qapi-features',
>> > + ' * Schema-defined QAPI features',
>> > + __doc__)
>> > +
>> > + self.features = {}
>>
>> mypy gripes
>>
>> scripts/qapi/features.py:29: error: Need type annotation for "features"
>> (hint: "features: Dict[<type>, <type>] = ...") [var-annotated]
>>
>> Elsewhere, we avoid rummaging in QAPISchema's innards by defining
>> suitable visit. If that's too much trouble for you now, I can take this
>> as is an clean up on top.
>>
>> > +
>> > + def visit_begin(self, schema: QAPISchema):
>>
>> mypy gripes
>>
>> scripts/qapi/features.py:31: error: Function is missing a return type
>> annotation [no-untyped-def]
>>
>> > + self.features = schema._feature_dict
>>
>> pylint gripes
>>
>> scripts/qapi/features.py:32:24: W0212: Access to a protected member
>> _feature_dict of a client class (protected-access)
>>
>> > +
>> > + def visit_end(self) -> None:
>> > + features = [
>> > + self.features[f]
>> > + for f in QAPISchemaFeature.SPECIAL_NAMES
>> > + ]
>> > +
>> > + features.extend(
>> > + sorted(
>> > + filter(lambda f: not f.is_special(),
>> > + self.features.values()),
>> > + key=lambda f: f.name)
>> > + )
>>
>> @features is schema._feature_dict.values() sorted by name in a certain
>> way, namely first the .SPECIAL_NAMES in order, then all the others in
>> alphabetical order.
>>
>> Why you do this is not immediately obvious. I guess it's to make the
>> generated enum a compatible extension of enum QapiSpecialFeature. That
>> one exists for use by schema-independent support code such
>> compat_policy_input_ok() and qobject_output_policy_skip().
>
> Yes, I wanted the overlapping enums vaules to match.
Needs a comment.
>> I further guess you sort the non-special features just to make the
>> generated code easier for humans to navigate.
>>
>> Correct?
>
> The remaining sort was just to give a predictable stable output,
> should QAPI usage of features be reordered.
We don't do that for enum QAPIEvent, and it hasn't inconvenienced us as
far as I can tell. No big deal, I just like consistency.
>> > +
>> > + self._genh.add("typedef enum {\n")
>> > + for f in features:
>> > + self._genh.add(f" {c_enum_const('qapi_feature', f.name)}")
>> > + if f.name in QAPISchemaFeature.SPECIAL_NAMES:
>> > + self._genh.add(f" = {c_enum_const('qapi', f.name)},\n" )
>>
>> pycodestyle gripes
>>
>> scripts/qapi/features.py:51:71: E202 whitespace before ')'
>>
>> > + else:
>> > + self._genh.add(",\n")
>> > +
>> > + self._genh.add("} " + c_name('QapiFeature') + ";\n")
>> > +
>>
>> pycodestyle gripes
>>
>> scripts/qapi/features.py:57:1: E302 expected 2 blank lines, found 1
>>
>> This part generates a C enum. It's similar to gen_enum() from types.py,
>> except we work with a list of QAPISchemaFeature here, and a list of
>> QAPISchemaEnumMember there.
>>
>> To reuse gen_enum() here, we'd have to make up a member list, like we do
>> in events.py for enum QAPIEvent.
>
> I'll have a look at that.
Reuse it only if it's easy for you. We can always improve on top.
>> > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
>> > index e97c978d38..5e14b1829b 100644
>> > --- a/scripts/qapi/schema.py
>> > +++ b/scripts/qapi/schema.py
>> > @@ -933,8 +933,11 @@ def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
>> > class QAPISchemaFeature(QAPISchemaMember):
>> > role = 'feature'
>> >
>> > + # Features which are standardized across all schemas
>> > + SPECIAL_NAMES = ['deprecated', 'unstable']
>> > +
>> > def is_special(self) -> bool:
>> > - return self.name in ('deprecated', 'unstable')
>> > + return self.name in QAPISchemaFeature.SPECIAL_NAMES
>> >
>> >
>> > class QAPISchemaObjectTypeMember(QAPISchemaMember):
>> > @@ -1138,6 +1141,11 @@ def __init__(self, fname: str):
>> > self._entity_list: List[QAPISchemaEntity] = []
>> > self._entity_dict: Dict[str, QAPISchemaDefinition] = {}
>> > self._module_dict: Dict[str, QAPISchemaModule] = OrderedDict()
>> > + self._feature_dict: Dict[str, QAPISchemaFeature] = {}
>> > +
>> > + for f in QAPISchemaFeature.SPECIAL_NAMES:
>> > + self._feature_dict[f] = QAPISchemaFeature(f, "special
>> > feature")
>>
>> mypy gripes
>>
>> scripts/qapi/schema.py:1147: error: Argument 2 to "QAPISchemaFeature"
>> has incompatible type "str"; expected "Optional[QAPISourceInfo]" [arg-type]
>>
>> We commonly use None as info value for built-in stuff, and that's why
>> it's Optional[QAPISourceInfo], not just QAPISourceInfo.
>
> Yeah, not sure what I was thinking here, looking again I
> should have passed "None"
>
>> But do we really need to make up some QAPISchemaFeature? Hmm. The
>> appended patch dumbs down ._feature_dict to a set.
See below for a possible reason to keep .feature_dict.
> I was following the same pattern as self._entity_dict and
> self._module_dict, rather than dumbing down to the bare
> minimum needed by my current use case. I don't mind which
> strategy we take.
.entity_dict maps the name to the one entity. Likewise .module_dict.
.feature_dict, however, maps it to the first of possibly many. That's
not wrong, just peculiar and possibly less than obvious to readers who
aren't familiar with how we represent features internally. Worth a
comment?
>> > +
>> > self._schema_dir = os.path.dirname(fname)
>> > self._make_module(QAPISchemaModule.BUILTIN_MODULE_NAME)
>> > self._make_module(fname)
>> > @@ -1258,6 +1266,15 @@ def _make_features(
>> > ) -> List[QAPISchemaFeature]:
>> > if features is None:
>> > return []
>> > +
>> > + for f in features:
>> > + feat = QAPISchemaFeature(f['name'], info)
>> > + if feat.name not in self._feature_dict:
>> > + if len(self._feature_dict) == 64:
>> > + raise Exception("Maximum of 64 schema features is
>> > permitted")
>>
>> The limit is an implementation restriction. Okay, we can lift it when
>> it bites us.
>>
>> However, the reporting is less than nice:
>>
>> $ python scripts/qapi-gen.py -o $$
>> tests/qapi-schema/features-too-many.json
>> Traceback (most recent call last):
>> File "/work/armbru/qemu/scripts/qapi-gen.py", line 19, in <module>
>> sys.exit(main.main())
>> ^^^^^^^^^^^
>> File "/work/armbru/qemu/scripts/qapi/main.py", line 96, in main
>> generate(args.schema,
>> File "/work/armbru/qemu/scripts/qapi/main.py", line 51, in generate
>> schema = QAPISchema(schema_file)
>> ^^^^^^^^^^^^^^^^^^^^^^^
>> File "/work/armbru/qemu/scripts/qapi/schema.py", line 1155, in __init__
>> self._def_exprs(exprs)
>> File "/work/armbru/qemu/scripts/qapi/schema.py", line 1482, in
>> _def_exprs
>> self._def_struct_type(expr)
>> File "/work/armbru/qemu/scripts/qapi/schema.py", line 1377, in
>> _def_struct_type
>> features = self._make_features(expr.get('features'), info)
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> File "/work/armbru/qemu/scripts/qapi/schema.py", line 1274, in
>> _make_features
>> raise Exception("Maximum of 64 schema features is permitted")
>> Exception: Maximum of 64 schema features is permitted
>
> Is there any better way to approach this error reporting ?
Raise QAPISemError in .check().
Hmm, then you need a QAPISourceInfo to pass. .feature_dict will give
you one: the .info of the feature added last.
