Re: [Pyobjc-dev] Indexed Accessor use gives "Bus Error"

[Ronald O. <ron...@ma...>]

On 8-dec-04, at 20:58, Neil Martinsen-Burrell wrote:

> On Dec 8, 2004, at 12:49, Bob Ippolito wrote:
>
>> On Dec 8, 2004, at 12:23 PM, Neil Martinsen-Burrell wrote:
>>
>>> I am having a problem implementing KVO-compliant indexed-accessor 
>>> methods using PyObjC.  The problem is a "Bus Error" when the program 
>>> is run.  The following seems to be a minimal reproduction of the 
>>> problem.  This is on 10.3.6 with the default Python installation and 
>>> PyObjC 1.1.  The nib simply contains an NSTableView with two columns 
>>> (with keys current and name) bound to an NSArrayController that is 
>>> bound to an instance of the following class (with contentArray = 
>>> TestList.list).  The crash report generated follows the program 
>>> listing.  Are index accessors not fully supported in PyObjC?  Am I 
>>> mis-declaring the accessors?  Thanks for any help you can give.
>>
>> countOfList should also be an objc.accessor (I think this is the 
>> reason for your crash)
>
> Indeed, this solves the bus error problem.  All of the accessors 
> needed to be explicitly declared as such.  If the accessors that are 
> supposed to return (void) are not objc.accessor's, then they raise an 
> error because they return the wrong type.  But accessors such as 
> countOfList that return data do not raise errors if they are not 
> objc.accessor's, they just cause the Bus Error.  Is this the desired 
> behavior?

It's the way it is :-(. As Bob mentioned random crashes are a 
side-effect of passing objects of the wrong type to ObjC code that 
isn't very careful in checking method signatures.

Ronald