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Re: [Qemu-devel] [PATCH v8 16/18] qapi: Move duplicate enum value checks
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v8 16/18] qapi: Move duplicate enum value checks to schema check() |
Date: |
Tue, 13 Oct 2015 13:37:56 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 10/13/2015 12:35 PM, Markus Armbruster wrote:
> Eric Blake <address@hidden> writes:
>
>> Similar to the previous commit, move the detection of a collision
>> in enum values from parse time to QAPISchemaEnumType.check().
>> This happens to also detect collisions in union branch names,
>> so for a decent error message, we have to determine if the enum
>> is implicit (and if so where the real collision lies).
>>
>> Testing this showed that the test union-bad-branch and
>> union-clash-branches were basically testing the same thing;
>> with the minor difference that the former clashes only in the
>> enum, while the latter also clashes in the C union member
>> names that would be generated. So delete the weaker test.
>>
>> No change to generated code.
>>
>> Signed-off-by: Eric Blake <address@hidden>
>>
>> +++ b/scripts/qapi.py
>> @@ -527,7 +527,6 @@ def check_union(expr, expr_info):
>> base = expr.get('base')
>> discriminator = expr.get('discriminator')
>> members = expr['data']
>> - values = {'MAX': '(automatic)', 'KIND': '(automatic)'}
>
> Stupid / tired question: I can see 'MAX' in the new code further down,
> but I can't see 'KIND'. Why? Was it perhaps covered by the previous
> patch?
MAX is covered by enum collisions. 'kind' is covered by the previous
patch's non-variant vs. branch-name collisions.
Hmm, maybe when respinning this I can simplify 15/18 to drop KIND from
this spot (because KIND is not part of the enum).
>>
>> def check(self, schema):
>> - assert len(set(self.values)) == len(self.values)
>> + # Check for collisions on the generated C enum values
>> + seen = {c_enum_const(self.name, 'MAX'): '(automatic MAX)'}
>> + for value in self.values:
>> + c_value = c_enum_const(self.name, value)
>> + if c_value in seen:
>> + # If the enum is implicit, report the error on behalf of
>> + # the union or alternate that triggered the enum
>> + if self.is_implicit():
>> + owner = schema.lookup_type(self.name[:-4])
>> + assert owner
>> + if isinstance(owner, QAPISchemaAlternateType):
>> + description = "Alternate '%s' branch" % owner.name
>> + else:
>> + description = "Union '%s' branch" % owner.name
>> + else:
>> + description = "Enum '%s' value" % self.name
>
> Computing a reasonable description distracts from the checking job.
> Suggest to outline this into a private method.
Good idea.
>> +++ b/tests/qapi-schema/alternate-clash.err
>> @@ -1 +1 @@
>> -tests/qapi-schema/alternate-clash.json:7: Alternate 'Alt1' member 'a_b'
>> clashes with 'a-b'
>> +tests/qapi-schema/alternate-clash.json:7: Alternate 'Alt1' branch 'a_b'
>> clashes with 'a-b'
>
> Our terminology isn't consistent: we use both "branch" and "case". Not
> this patch's problem to fix.
>
>> diff --git a/tests/qapi-schema/enum-clash-member.err
>> b/tests/qapi-schema/enum-clash-member.err
>> index 48bd136..84030c5 100644
>> --- a/tests/qapi-schema/enum-clash-member.err
>> +++ b/tests/qapi-schema/enum-clash-member.err
>> @@ -1 +1 @@
>> -tests/qapi-schema/enum-clash-member.json:2: Enum 'MyEnum' member 'ONE'
>> clashes with 'one'
>> +tests/qapi-schema/enum-clash-member.json:2: Enum 'MyEnum' value 'ONE'
>> clashes with 'one'
>
> I actually prefer calling ONE a member of MyEnum, because that leaves
> value for its actual value.
>
> For what it's worth, the C standard also talks about "members of an
> enumeration".
Easy enough to fix.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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[Qemu-devel] [PATCH v8 18/18] qapi: Detect base class loops, Eric Blake, 2015/10/13
[Qemu-devel] [PATCH v8 16/18] qapi: Move duplicate enum value checks to schema check(), Eric Blake, 2015/10/13
[Qemu-devel] [PATCH v8 06.5/18] qapi: Drop redundant args-member-array test, Eric Blake, 2015/10/13
[Qemu-devel] [PATCH v8 06/18] qapi: Drop redundant flat-union-reverse-define test, Eric Blake, 2015/10/15
[Qemu-devel] [PATCH v8 02/18] qapi: Prepare for errors during check(), Eric Blake, 2015/10/15
[Qemu-devel] [PATCH v8 13/18] qapi: Track owner of each object member, Eric Blake, 2015/10/15
[Qemu-devel] [PATCH v8 17/18] qapi: Add test for alternate branch 'kind' clash, Eric Blake, 2015/10/15