Re: Problem with NSTextView

[Fred Kiefer]

When decoding actions we call, NSSelectorFromString() and this 
internally uses sel_registerName(). According to your mail this is the 
right way to do it even for clang.
You talk about a wrong way to generate selectors, could you explain what 
that would be?

Fred

On 29.01.2012 12:54, David Chisnall wrote:
> The runtime won't generate this warning if the selector has no type
> information (selectors returned by @selector() are untyped, for
> example).  If it comes from nib loading, then it sounds like we're
> creating the selector the wrong way.  We should be calling
> sel_registerName(), which will give an untyped selector.  If the nib
> is storing the type information, then I'd expect it to be an
> IBAction, but the error is appearing because it is NOT an
> IBAction...
>
> David
>
> P.S. These messages are not shown in release builds of the runtime,
> but the extra cost of the double lookup for incorrect type signatures
> is still present.
>
> On 28 Jan 2012, at 21:29, Eric Wasylishen wrote:
>
> > Hi, Based on Sebastain's bactrace, I think it's a spurious warning:
> > the method isn't actually being called with an incorrect signature,
> > the menu update code is just calling class_respondsToSelector() to
> > check if an object responds to the selector "copy:". The selector
> > being passed probably comes from nib loading, so any type info is
> > random.
> >
> > Eric
> >
> > > #0  fprintf (fp=0x2d086310, fmt=0x2ccc6c6f "Calling [%s %c%s]
> > > with incorrect signature.  Method has %s, selector has %s\n") at
> > > /usr/src/lib/libc/stdio/fprintf.c:44 #1  0x0ccdb448 in
> > > objc_selector_type_mismatch (cls=0xcfbd5274, selector=0xcfbd5274,
> > > result=0xcfbd5274) at sendmsg2.c:37 #2  0x0ccdc22c in
> > > objc_get_slot (cls=Unhandled dwarf expression opcode 0x0 ) at
> > > sendmsg2.c:307 #3  0x0ccdc26f in class_respondsToSelector
> > > (cls=dwarf2_read_address: Corrupted DWARF expression. ) at
> > > sendmsg2.c:322 #4  0x0a102e78 in -[NSObject respondsToSelector:]
> > > (self=dwarf2_read_address: Corrupted DWARF expression. ) at
> > > NSObject.m:2096 #5  0x09977ff1 in -[NSApplication(Private)
> > > _targetForAction:keyWindow:mainWindow:] (self=0x8a57a984,
> > > _cmd=0x29805088, aSelector=0x8be49550, keyWindow=0x7fbfe304,
> > > mainWindow=0x7fbfe304) at NSApplication.m:3897 #6  0x0996dae1 in
> > > -[NSApplication targetForAction:] (self=0x8a57a984,
> > > _cmd=0x29804d08, aSelector=0x8be49550) at NSApplication.m:2290 #7
> > > 0x0996d98c in -[NSApplication targetForAction:to:from:]
> > > (self=0x8a57a984, _cmd=0x29837640, theAction=0x8be49550,
> > > theTarget=0x0, sender=0x84fdf904) at NSApplication.m:2275 #8
> > > 0x09b2891c in -[NSMenu update] (self=0x80ffd844, _cmd=0x29837190)
> > > at NSMenu.m:1151 #9  0x09b287f2 in -[NSMenu update]
> > > (self=0x81921144, _cmd=0x29805228) at NSMenu.m:1146 #10
> > > 0x09969901 in -[NSApplication run] (self=0x8a57a984,
> > > _cmd=0x297fe900) at NSApplication.m:1570 #11 0x0992466d in
> > > NSApplicationMain (argc=1, argv=0xcfbd5c14) at Functions.m:91 #12
> > > 0x1c005ec7 in ___start () #13 0x1c005e42 in _start ()
> > >
> > >
> > > Sebastian
> > >
> > > > On 28 Jan 2012, at 13:17, Sebastian Reitenbach wrote:
> > > >
> > > > > Method has v12@0:4@8, selector has @12@0:4@8
> > > >
> > > > This looks potentially dangerous.  The caller is expecting the
> > > > method to return an object, but the method is a standard
> > > > IBAction (i.e. returning void).  If the caller does anything
> > > > with the return value, then it will likely crash...
> > > >
> > > > David