Re: Curious about copyWithZone message from NSArrayController in "GC required" project

FROM : Bill Bumgarner
DATE : Sun Jan 13 23:54:56 2008

On Jan 13, 2008, at 2:48 PM, Luke Evans wrote:
>> >First and foremost, -copyWithZone: has absolutely nothing to do 
>> with the differences between GC and non-GC.  As its name implies, 
>> it is all about copying an object, something that must be done in 
>> either GC or non-GC.
>>

> Makes sense.  I was wondering though if the fact I had a property 
> declared on A to get the array of B's made a difference.  Reading 
> the docs on properties highlights some differences between GC and 
> non-GC, though from what you are saying, this should not effect a 
> copy.


Only if you declared the property to use 'copy' on set.  Then, as 
expected, it would attempt to copy the object.

>> >So -- first question -- what is triggering the -copyWithZone: 
>> being sent to an instance of B in the first place?

>
> Perhaps I need to take a look to see _exactly_ who is sending the 
> copyWithZone message to B, but the only time I've had this manifest 
> is when I've A's property that returns the array of B's bound as the 
> content of the NSArrayController - which generates some UI for the 
> list of B's.  I've used put B's on all manner of collections 
> (arrays, sets) directly, with no hint of anybody calling 
> "copyWithZone".


You mentioned that you had implemented a -copyWithZone: on B?  Can 
you set a breakpoint on that and see what backtrace barfs up as a 
result?