Re: [Qemu-devel] [PATCH v6 12/27] qapi: add a dictionnary form with 'name' key for enum members

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Hi
On Wed, Dec 5, 2018 at 10:02 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> In subject, s/dictionnary/dictionary/
>
> Marc-André Lureau <marcandre.lureau@redhat.com> writes:
>
> > Desugar the enum NAME form to { 'name': NAME }. This will allow to add
> > new enum members, such as 'if' in the following patch.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  scripts/qapi/common.py                        | 47 ++++++++++++++++---
> >  tests/Makefile.include                        |  3 +-
> >  tests/qapi-schema/enum-bad-member.err         |  1 +
> >  ...-dict-member.exit => enum-bad-member.exit} |  0
> >  tests/qapi-schema/enum-bad-member.json        |  2 +
> >  ...um-dict-member.out => enum-bad-member.out} |  0
> >  .../qapi-schema/enum-dict-member-unknown.err  |  2 +
> >  .../qapi-schema/enum-dict-member-unknown.exit |  1 +
> >  .../qapi-schema/enum-dict-member-unknown.json |  2 +
> >  .../qapi-schema/enum-dict-member-unknown.out  |  0
> >  tests/qapi-schema/enum-dict-member.err        |  1 -
> >  tests/qapi-schema/enum-dict-member.json       |  2 -
> >  tests/qapi-schema/enum-missing-data.err       |  2 +-
> >  13 files changed, 51 insertions(+), 12 deletions(-)
> >  create mode 100644 tests/qapi-schema/enum-bad-member.err
> >  rename tests/qapi-schema/{enum-dict-member.exit => enum-bad-member.exit} (100%)
> >  create mode 100644 tests/qapi-schema/enum-bad-member.json
> >  rename tests/qapi-schema/{enum-dict-member.out => enum-bad-member.out} (100%)
> >  create mode 100644 tests/qapi-schema/enum-dict-member-unknown.err
> >  create mode 100644 tests/qapi-schema/enum-dict-member-unknown.exit
> >  create mode 100644 tests/qapi-schema/enum-dict-member-unknown.json
> >  create mode 100644 tests/qapi-schema/enum-dict-member-unknown.out
> >  delete mode 100644 tests/qapi-schema/enum-dict-member.err
> >  delete mode 100644 tests/qapi-schema/enum-dict-member.json
> >
> > diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
> > index cf8dab2866..e9fb736d46 100644
> > --- a/scripts/qapi/common.py
> > +++ b/scripts/qapi/common.py
> > @@ -740,6 +740,10 @@ def check_event(expr, info):
> >                 allow_metas=meta)
> >
> >
> > +def enum_get_names(expr):
> > +    return [e['name'] for e in expr['data']]
> > +
> > +
> >  def check_union(expr, info):
> >      name = expr['union']
> >      base = expr.get('base')
> > @@ -799,7 +803,7 @@ def check_union(expr, info):
> >          # If the discriminator names an enum type, then all members
> >          # of 'data' must also be members of the enum type.
> >          if enum_define:
> > -            if key not in enum_define['data']:
> > +            if key not in enum_get_names(enum_define):
> >                  raise QAPISemError(info,
> >                                     "Discriminator value '%s' is not found in "
> >                                     "enum '%s'"
> > @@ -831,10 +835,10 @@ def check_alternate(expr, info):
> >          if qtype == 'QTYPE_QSTRING':
> >              enum_expr = enum_types.get(value)
> >              if enum_expr:
> > -                for v in enum_expr['data']:
> > +                for v in enum_get_names(enum_expr):
> >                      if v in ['on', 'off']:
> >                          conflicting.add('QTYPE_QBOOL')
> > -                    if re.match(r'[-+0-9.]', v): # lazy, could be tightened
> > +                    if re.match(r'[-+0-9.]', v):  # lazy, could be tightened
>
> Unrelated change.
>

ok

> >                          conflicting.add('QTYPE_QNUM')
> >              else:
> >                  conflicting.add('QTYPE_QNUM')
>
> The helper enum_get_names() is used just twice.
>
> The second instance
>
>                 for v in enum_get_names(enum_expr):
>
> could just as well iterate over enum_expr
>
>                 for d in enum_expr['data']:
>                     v = d['name']
>
> The first instance could simply be inlined then.

well, with unnormalized form (your request below), this becomes even
less readable. I'll keep it, even if it's a one-liner, I much prefer
an explicit function name and common code.

>
> > @@ -847,19 +851,34 @@ def check_alternate(expr, info):
> >              types_seen[qt] = key
> >
> >
> > -def check_enum(expr, info):
> > +def normalize_enum(expr, info):
> >      name = expr['enum']
> >      members = expr.get('data')
> > -    prefix = expr.get('prefix')
> >
> >      if not isinstance(members, list):
> >          raise QAPISemError(info,
> >                             "Enum '%s' requires an array for 'data'" % name)
> > +
> > +    # translate short member form to dict form
> > +    for i, member in enumerate(members):
> > +        if not isinstance(member, dict):
> > +            member = {'name': member}
> > +            members[i] = member
>
> Simpler:
>
>        members = [m if isinstance(m, dict) else {'name': m} for m in members]
>

Yes, except that this doesn't change the dict in place. No pb, updated.

> > +
> > +
> > +def check_enum(expr, info):
> > +    name = expr['enum']
> > +    members = expr.get('data')
>
> Preexisting: this should be expr['data'], because we already checked
> required keys.
>

ok

> > +    prefix = expr.get('prefix')
> > +
> >      if prefix is not None and not isinstance(prefix, str):
> >          raise QAPISemError(info,
> >                             "Enum '%s' requires a string for 'prefix'" % name)
> > +
> >      for member in members:
> > -        check_name(info, "Member of enum '%s'" % name, member,
> > +        source = "dictionary member of enum '%s'" % name
> > +        check_known_keys(info, source, member, ['name'], [])
> > +        check_name(info, "Member of enum '%s'" % name, member['name'],
> >                     enum_member=True)
> >
> >
> > @@ -921,6 +940,13 @@ def check_exprs(exprs):
> >      for builtin in builtin_types.keys():
> >          all_names[builtin] = 'built-in'
> >
> > +    # Normalize exprs
> > +    for expr_elem in exprs:
> > +        expr = expr_elem['expr']
> > +        info = expr_elem['info']
> > +        if 'enum' in expr:
> > +            normalize_enum(expr, info)
> > +
>
> As demonstrated by tests/qapi-schema/enum-missing-data.json below, the
> error message for
>
>     {'enum': 'MyEnum'}
>
> changes from
>
>     Key 'data' is missing from enum 'MyEnum'
>
> to
>
>     Enum 'MyEnum' requires an array for 'data'
>
> because you normalize before checking keys.  I don't think that's a good
> idea.

The alternative is to check and normalize after, sure it's a bit more
user-friendly, ok.

>
> >      # Learn the types and check for valid expression keys
> >      for expr_elem in exprs:
> >          expr = expr_elem['expr']
>            info = expr_elem['info']
>            doc = expr_elem.get('doc')
>
>            if 'include' in expr:
>                continue
>
>            if not doc and doc_required:
>                raise QAPISemError(info,
>                                   "Expression missing documentation comment")
>
>            if 'enum' in expr:
>                meta = 'enum'
>                check_keys(expr_elem, 'enum', ['data'], ['if', 'prefix'])
>
> This seems a better place to call normalize_enum(expr, info).
>
>                enum_types[expr[meta]] = expr
>            elif 'union' in expr:
> > @@ -1640,7 +1666,14 @@ class QAPISchema(object):
> >                                              qtype_values, 'QTYPE'))
> >
> >      def _make_enum_members(self, values):
> > -        return [QAPISchemaMember(v) for v in values]
> > +        enum = []
> > +        for v in values:
> > +            if isinstance(v, dict):
> > +                name = v['name']
> > +            else:
> > +                name = v
> > +            enum.append(QAPISchemaMember(name))
> > +        return enum
>
> Despite normalization to the long form, we still deal with both the long
> and the short form here.  Three callers:
>
> * _def_predefineds(): passes the short form.
>
> * _make_implicit_enum_type(): passes the short form until PATCH 19
>   changes it to pass the long form.
>
> * _def_enum_type(): passes the long form.
>
> I believe always passing the long form would be simpler.

ok, I'll add a patch for def_predefineds()

>
> >
> >      def _make_implicit_enum_type(self, name, info, ifcond, values):
> >          # See also QAPISchemaObjectTypeMember._pretty_owner()
> > diff --git a/tests/Makefile.include b/tests/Makefile.include
> > index a49282704e..8e1b122cf2 100644
> > --- a/tests/Makefile.include
> > +++ b/tests/Makefile.include
> > @@ -482,10 +482,11 @@ qapi-schema += double-data.json
> >  qapi-schema += double-type.json
> >  qapi-schema += duplicate-key.json
> >  qapi-schema += empty.json
> > +qapi-schema += enum-bad-member.json
> >  qapi-schema += enum-bad-name.json
> >  qapi-schema += enum-bad-prefix.json
> >  qapi-schema += enum-clash-member.json
> > -qapi-schema += enum-dict-member.json
> > +qapi-schema += enum-dict-member-unknown.json
> >  qapi-schema += enum-int-member.json
> >  qapi-schema += enum-member-case.json
> >  qapi-schema += enum-missing-data.json
> > diff --git a/tests/qapi-schema/enum-bad-member.err b/tests/qapi-schema/enum-bad-member.err
> > new file mode 100644
> > index 0000000000..211db9e6fc
> > --- /dev/null
> > +++ b/tests/qapi-schema/enum-bad-member.err
> > @@ -0,0 +1 @@
> > +tests/qapi-schema/enum-bad-member.json:2: Member of enum 'MyEnum' requires a string name
> > diff --git a/tests/qapi-schema/enum-dict-member.exit b/tests/qapi-schema/enum-bad-member.exit
> > similarity index 100%
> > rename from tests/qapi-schema/enum-dict-member.exit
> > rename to tests/qapi-schema/enum-bad-member.exit
> > diff --git a/tests/qapi-schema/enum-bad-member.json b/tests/qapi-schema/enum-bad-member.json
> > new file mode 100644
> > index 0000000000..98da6828b4
> > --- /dev/null
> > +++ b/tests/qapi-schema/enum-bad-member.json
> > @@ -0,0 +1,2 @@
> > +# we reject any enum member that is not a string
> > +{ 'enum': 'MyEnum', 'data': [ [ ] ] }
> > diff --git a/tests/qapi-schema/enum-dict-member.out b/tests/qapi-schema/enum-bad-member.out
> > similarity index 100%
> > rename from tests/qapi-schema/enum-dict-member.out
> > rename to tests/qapi-schema/enum-bad-member.out
>
> This replaces enum-dict-member.json.  Okay.  Took me a while to see this
> %-/
>
> > diff --git a/tests/qapi-schema/enum-dict-member-unknown.err b/tests/qapi-schema/enum-dict-member-unknown.err
> > new file mode 100644
> > index 0000000000..76bd0471db
> > --- /dev/null
> > +++ b/tests/qapi-schema/enum-dict-member-unknown.err
> > @@ -0,0 +1,2 @@
> > +tests/qapi-schema/enum-dict-member-unknown.json:2: Unknown key 'bad-key' in dictionary member of enum 'MyEnum'
> > +Valid keys are 'name'.
> > diff --git a/tests/qapi-schema/enum-dict-member-unknown.exit b/tests/qapi-schema/enum-dict-member-unknown.exit
> > new file mode 100644
> > index 0000000000..d00491fd7e
> > --- /dev/null
> > +++ b/tests/qapi-schema/enum-dict-member-unknown.exit
> > @@ -0,0 +1 @@
> > +1
> > diff --git a/tests/qapi-schema/enum-dict-member-unknown.json b/tests/qapi-schema/enum-dict-member-unknown.json
> > new file mode 100644
> > index 0000000000..6664c59201
> > --- /dev/null
> > +++ b/tests/qapi-schema/enum-dict-member-unknown.json
> > @@ -0,0 +1,2 @@
> > +# we reject any enum member that is not a string or a dict with 'name'
> > +{ 'enum': 'MyEnum', 'data': [ { 'name': 'foo', 'bad-key': 'str' } ] }
> > diff --git a/tests/qapi-schema/enum-dict-member-unknown.out b/tests/qapi-schema/enum-dict-member-unknown.out
> > new file mode 100644
> > index 0000000000..e69de29bb2
> > diff --git a/tests/qapi-schema/enum-dict-member.err b/tests/qapi-schema/enum-dict-member.err
> > deleted file mode 100644
> > index 8ca146ea59..0000000000
> > --- a/tests/qapi-schema/enum-dict-member.err
> > +++ /dev/null
> > @@ -1 +0,0 @@
> > -tests/qapi-schema/enum-dict-member.json:2: Member of enum 'MyEnum' requires a string name
> > diff --git a/tests/qapi-schema/enum-dict-member.json b/tests/qapi-schema/enum-dict-member.json
> > deleted file mode 100644
> > index 79672e0f09..0000000000
> > --- a/tests/qapi-schema/enum-dict-member.json
> > +++ /dev/null
> > @@ -1,2 +0,0 @@
> > -# we reject any enum member that is not a string
> > -{ 'enum': 'MyEnum', 'data': [ { 'value': 'str' } ] }
> > diff --git a/tests/qapi-schema/enum-missing-data.err b/tests/qapi-schema/enum-missing-data.err
> > index ba4873ae69..b8ccae071b 100644
> > --- a/tests/qapi-schema/enum-missing-data.err
> > +++ b/tests/qapi-schema/enum-missing-data.err
> > @@ -1 +1 @@
> > -tests/qapi-schema/enum-missing-data.json:2: Key 'data' is missing from enum 'MyEnum'
> > +tests/qapi-schema/enum-missing-data.json:2: Enum 'MyEnum' requires an array for 'data'