Re: Disappointed by GNUstep

[Wolfgang Lux]

Hi Sergei,

> On 2022-02-06 22:50:07 +0400 Fred Kiefer <fredkiefer@gmx.de> wrote:
> 
> > Your change looks great to me, as always. Let's just hope it does
> > not 
> > break 
> > anything for the other two issues that caused the different changes
> > on that 
> > code. 
> 
> That one issue in December was due to deallocation of
> NSPopUpButtonCell
> causing to call -[synchronizeTitleAndSelectedItem] followed with 
> updating
> of the _menuItem, its _menu  and all dependants (validators) where
> the segfault occurs because one of the validators has been
> deallocated 
> already.
> 
> #0  0x00007ffff6ee9415 in objc_msg_lookup () from 
> /usr/lib/x86_64-linux-gnu/libobjc.so.4
> #1  0x00007ffff7845af0 in -[NSApplication targetForAction:to:from:] 
> (self=0x5555559683a0, _cmd=0x7ffff7c72330
> <_OBJC_SELECTOR_TABLE+2384>,
>      theAction=0x555555ad8570, theTarget=0x555555e464b0, 
> sender=0x555555d1feb0) at NSApplication.m:2294
> #2  0x00007ffff7949ca8 in -[NSMenu _autoenableItem:] 
> (self=0x555555d1fa40, _cmd=0x7ffff7c723f0
> <_OBJC_SELECTOR_TABLE+2576>,
>      item=0x555555d1feb0) at NSMenu.m:1184
> #3  0x00007ffff794a078 in -[NSMenu update] (self=0x555555d1fa40, 
> _cmd=0x7ffff7c721a0 <_OBJC_SELECTOR_TABLE+1984>) at NSMenu.m:1260
> #4  0x00007ffff7948f56 in -[NSMenu itemChanged:]
> (self=0x555555d1fa40, 
> _cmd=0x7ffff7c79650 <_OBJC_SELECTOR_TABLE+496>,
>      anObject=0x555555d1fdd0) at NSMenu.m:878
> #5  0x00007ffff7957bdd in -[NSMenuItem setImage:] 
> (self=0x555555d1fdd0, _cmd=0x7ffff7c98cf0
> <_OBJC_SELECTOR_TABLE+1168>, 
> image=0x0)
>      at NSMenuItem.m:375
> #6  0x00007ffff797c589 in -[NSPopUpButtonCell setMenuItem:] 
> (self=0x555555d1fc60, _cmd=0x7ffff7c98da0
> <_OBJC_SELECTOR_TABLE+1344>, 
> item=0x0)
>      at NSPopUpButtonCell.m:652
> #7  0x00007ffff797cf77 in -[NSPopUpButtonCell 
> synchronizeTitleAndSelectedItem] (self=0x555555d1fc60,
>      _cmd=0x7ffff7c98ac0 <_OBJC_SELECTOR_TABLE+608>) at 
> NSPopUpButtonCell.m:854
> #8  0x00007ffff797b631 in -[NSPopUpButtonCell setMenu:] 
> (self=0x555555d1fc60, _cmd=0x7ffff7c98940 <_OBJC_SELECTOR_TABLE+224>,
> menu=0x0)
>      at NSPopUpButtonCell.m:218
> #9  0x00007ffff797b284 in -[NSPopUpButtonCell dealloc] 
> (self=0x555555d1fc60, _cmd=0x7ffff7534970 <_OBJC_SELECTOR_TABLE+48>)
>      at NSPopUpButtonCell.m:153
> 
> May be doing that is excessive in the context  of deallocation?
> 
> The attached patch changes the -[dealloc] to do the code chunk 
> equivalent to -[setMenu:nil]
> avoiding that -[NSPopUpButtonCell synchronizeTitleAndSelectedItem]
> and 
> following.
> 

didn't have time to look at your second message earlier.
I like the idea of avoiding the call to setMenu: altogether. That said,
there is a little problem with your patch: It lets the menu leak. There
should be a DESTROY(_menu) or RELEASE(_menu) statement after removing
the observer. And I would remove the setMenuView: call. The
NSPopUpButtonCell implementation of this method just changes the value
of a non-retained field and if any subclass of NSPopUpButtonCell has an
override for setMenu: it would be better to avoid calling it at this
point because deallocation has already been performed for such a
subclass.

Wolfgang