> To clarify, are you saying that the warning may lead to false positives when > used in subclasses ?
Seems I was wrong. Just checked the behaviour with backing storage - it also leads to a circular container problem. Also, you can find attachment with a ‘proper’ implementation, which also covers subclassing. P.S. I didn’t measure performance, but I think this implementation might have negative impact on the speed. -- AlexDenisov Software Engineer, http://lowlevelbits.org
proper_fix_for_circular_containers.patch
Description: Binary data
> On 30 Jul 2015, at 18:18, Argyrios Kyrtzidis <kyrtzi...@apple.com> wrote:
>
>
>> On Jul 30, 2015, at 1:05 AM, AlexDenisov <1101.deb...@gmail.com> wrote:
>>
>> The patch is a simplest fix for crash when CheckObjCCircularContainer
>> applies to a message to a ’super’, e.g.:
>>
>> @implementation Foo : NSMutableArray
>> - foo {
>> [super addObject:nil];
>> }
>> @end
>>
>>
>> This is, probably, not a proper fix for the problem,
>> but initial patch wasn’t intended to apply checks to any kind
>> of subclassing, because it, imho, over-complicates implementation:
>
> To clarify, are you saying that the warning may lead to false positives when
> used in subclasses ?
> If that’s the case could we just disable it inside collection subclasses, at
> least until the false positives can be addressed ?
>
>>
>> This particular problem touches subclassing from a class-cluster,
>> which means that the concrete subclass will have some backing storage, e.g.:
>>
>> @implementation FootableArray : NSMutableArray
>> {
>> NSMutableArray *_backingStorage;
>> }
>>
>> - addObject:(id)object {
>> [_backingStorage addObject:object];
>> }
>>
>> @end
>>
>> In this case even adding `self` to `self` would not lead to a circular
>> container:
>>
>> - foo {
>> [self addObject:self]; // puts `self` into the `_backingStorage`
>> }
>>
>> I would apply this patch as is and postpone a ‘proper and bullet-proof
>> implementation’
>> when I, or somebody who is also interested, will have more time.
>>
>> If there are any questions/suggestions/objections - let’s discuss them.
>> --
>> AlexDenisov
>> Software Engineer, http://lowlevelbits.org
>>
>>
>> <fix_circular_container_crash.patch>
>
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