Re: another exception triggered by OGo in gnustep-base

[Fred Kiefer]

On 29.07.2011 19:25, Sebastian Reitenbach wrote:
> On Friday, July 29, 2011 15:26 CEST, "Sebastian
> Reitenbach"<sebastia@l00-bugdead-prods.de>  wrote:
>
> > On Friday, July 29, 2011 15:00 CEST, David
> > Chisnall<theraven@sucs.org>  wrote:
> >
> > > On 29 Jul 2011, at 13:51, Sebastian Reitenbach wrote:
> > >
> > > > I found this documentation here:
> > > > http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSData_Class/Reference/Reference.html
> > > >
> > > > Initializes a newly allocated data object by adding to it length >>>> 
bytes of data from the buffer bytes.
> > > > but it doesn't state that a subclass should implement it???
> > > >
> > > > SkyDecodeWrapperData is a subclass of NSData, so I should
> > > > implement that method there?
> > >
> > > I think this is a GNUstep bug.  The default implementation o
> > > initWithBytesNoCopy:length:freeWhenDone: should probably be
> > > releasing self and returning a new instance of the class that
> > > does support this initialiser (as happens in the placeholder data
> > > class).
>
> While fiddling around there, I found that NSDataMalloc implements
> initWithBytesNoCopy:length:freeWhenDone:, and I looked at it how it
> is done there, and implemented it similarly in OGos
> SkyDecodeWrapperData, which now works like a charm ;)

I think both OGo and libFoundation where wrong here. The method 
-initWithBytesNoCopy:length:freeWhenDone: is the designated initializer 
of the class NSData, although this isn't stated in the Apple 
documentation, but the initializer with the most arguments takes over 
this role and all other initializers should call this method.

libFoundation tried to implement that method with other initializers, 
which is just wrong. And OGO forgot to implement that method in their 
own subclass. Anyway, from your back trace it looks like the class 
[SkyDecodeWrapperData -initWithData:encoding:] calls [NSData -init], 
perhaps as a super call, this also looks wrong to me. although it 
normally wont do much harm.