Re: _e_info in NSException.h

[Sebastian Reitenbach]

Hi Richard,
Richard Frith-Macdonald <richard@tiptree.demon.co.uk> wrote: 
> 
> On 14 Jan 2008, at 07:35, Sebastian Reitenbach wrote:
> 
> > Hi,
> >
> > Richard Frith-Macdonald <richard@tiptree.demon.co.uk> wrote:
> >>
> >> On 13 Jan 2008, at 21:20, Sebastian Reitenbach wrote:
> >>
> >>> Hi,
> >>>
> >>> after I got sope and sogo working with gnustep-make 2 and gnustep- 
> >>> base
> >>> 1.14.1, I tried to compile against gnustep-base1.15.2.
> >>>
> >>> sope compilation ended in an error:
> >>> Structure has no member named: _e_info
> >>> there is a line:
> >>> ASSIGN(self->_e_info, _userInfo);
> >>>
> >>> after a bit digging I figured out that it was removed not long ago
> >>> from
> >>> NSException.h:
> >>>
> >>> http://svn.gna.org/viewcvs/gnustep?rev=25681&view=rev
> >>> after adding again:
> >>> NSDictionary *_e_info;
> >>>
> >>> sope compiled again.
> >>>
> >>> I wonder why was it removed? or is it an error to set it, in the  
> >>> first
> >>> place?
> >>
> >> It's an error to try to set it in the first place  ... the leading
> >> underscore in the name if the instance variable tells you that this
> >> is a private instance variable intended for internal use only.  In
> >> 1.15.2 it has been replaced by _reserved (which is used only when
> >> necessary to store additional information .... user info and/or
> >> stacktrace ... in an exception).
> > ah, thanks, understood.
> >
> >> NSException has no external instance variables ... I guess if the
> >> sope code wants to store extra information in an exception it should
> >> create a new exception based on the values returned by the methods of
> >> the original one.
> >>
> >
> > In sope I find this:
> >
> > #if GNUSTEP_BASE_LIBRARY
> > /* FIXME: TODO: move someplace better (hh: NGExtensions...) */
> > @implementation NSException(setUserInfo)
> >
> > - (id)setUserInfo:(NSDictionary *)_userInfo {
> >   ASSIGN(self->_e_info, _userInfo);
> >   return self;
> > }
> >
> > @end /* NSException(setUserInfo) */
> > #endif
> >
> > and then later in the file, setUserInfo is used.
> > I took a quick look and found setUserInfo available in  
> > libFoundation, and
> > there is no #if COCOOA, so I assume it is there available too, (I  
> > have no
> > MAC to make sure).
> 
> I checked the MacOS foundation headers ... no such method.
> I then write a small test program:
> 
>       NSException *e;
>       
>       e = [NSException exceptionWithName: @"aaa" reason: @"bbb" userInfo:  
> nil];
>       [e setUserInfo: [NSDictionary dictionary]];
> 
> Running this produced
> 
> 2008-01-14 08:08:05.166 TestTool[2478] *** Uncaught exception:  
> <NSInvalidArgumentException> *** -[NSException setUserInfo:]:  
> selector not recognized [self = 0x303000]
> 
> So the method definitely does not exist in Cocoa.
thanks for testing this.

> 
> > In my eyes it would make most sense to add
> > setUserInfo to NSException in gnustep-base, and then remove all the  
> > #if
> > GNUSTEP_BASE_LIBRARY stuff from sope, or at least replace it for  
> > now with
> > sth. that checks for the GNUSTEP_BASE version.
> >
> > Would that make sense, or is a too bad idea?
> 
> Given that the method does not exist except in libFoundation, it  
> seems to me that the correct thing to do is to go through the sope  
> code and remove all uses of it.  Actually if the code does not  
> contain an implementation for Cocoa, maybe sope does not actually use  
> it and all you need to do is remove the code which attempts to  
> implement it for GNUstep.

Yes, then obviously a bit more work, but seems reasonable. I need to discuss 
this on the sope developer list.

thanks a lot
Sebastian