Re: ProjectCenter segfault

[Stefan Urbanek]

On 2003-07-11 01:50:49 +0200 Alexander Malmberg <alexander@malmberg.org> wrote:

> Benhur Stein wrote:
> > I'm getting those too. I think they are related to the last changes in base
> > to better support DO. It seems that message forwarding is not always working
> > well.
> [snip]
>
> I've noticed what might be a related problem in some apps. It seems that
> combining forwarding with -performSelector: no longer works unless the
> performed method has a return type (id). There seem to be issues with
> using untyped selectors (although there is an id return from
> -performSelector:, the forwarding code can't know this). Haven't looked
> closely at it yet, though.

If you want to forward, you hav eto know types. You should get types from 
object which are you forwarding to, however -base used to use random types from 
objc runtime.


> It's also pickier now than before. Forwarding won't work at all unless
> you implement -methodSignatureForSelector:.

Sure you have to. Even in apple docs you have higlighted text in a box saying:

Note: To respond to methods that your object does not itself recognize, you 
must override methodSignatureForSelector: in addition to forwardInvocation:. 
The mechanism for forwarding messages uses information obtained from 
methodSignatureForSelector: to create the NSInvocation object to be forwarded. 
Your overriding method must provide an appropriate method signature for the 
given selector, either by preformulating one or by asking another object for 
one.

And it is logical. I think that the latest change, and usage of selector from 
object to which invocation is being sent, revealed other bugs in GS (think of 
it as Good).

Stefan