[Debian GNUstep maintainers] Bug#1087735: gworkspace.app: NSImage(instance) does not recognize subviews

[Fred Kiefer]

Thank you Yavor for this patch. It looks correct to me and should resolve this specific issue. As for the code in the whole Address framework it will need a lot more of cleanup. Just skimming over it I noticed dozens of issues. i am quite surprised that this code does anything useful at all. If this library is in actual use, Riccardo and I should sit down together and try to clean it up. Otherwise it will come back and haunt us :-)
Great to see how you all worked together to understand and resolve this specific problem.

Cheers,
Fred


> Am 20.11.2024 um 02:23 schrieb Yavor Doganov <yavor at gnu.org>:
> 
> Control: reassign -1 libaddressview0 0.4.8-5
> Control: retitle -1 [i386] VCFViewer inspector aborts GWorkspace, making it unusable
> Control: affects -1 gworkspace.app
> Control: tags -1 + patch
> 
> Paul Seelig wrote:
>> Looks like finally found the root cause for making GWorkspace
>> malfunction on i386!
> 
> Indeed!
> 
>> There is a package named 'addresses-goodies-for-gnustep' containing
>> "VCFViewer - A GWorkspace inspector for viewing .vcf files".  I had this
>> package installed and apparently this pulls in libAddressView. In amd64
>> this doesn't provoke GWorkspace any different, but in i386 it obviously
>> does.
> 
> This is basically rarely tested code.  The upstream build system does
> not build anything in the Goodies directory by default and we (we ==
> Debian GNUstep team) enabled the VCFViewer inspector recently (in
> 0.4.8-5, uploaded 27th of September to unstable).  Excellent catch,
> once again I'd like to express my gratitude for your bug report.
> 
>> Once i deinstalled 'addresses-goodies-for-gnustep' on i386, GWorkspace
>> worked fine as expected.
> 
> Armed with this information, I was able to reproduce on my i386
> machine.  But I get SIGSEGV and not your uncaught exception(s).  The
> backtrace is:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0xb727a373 in objc_msg_lookup () from /lib/i386-linux-gnu/libobjc.so.4
> (gdb) bt
> #0  0xb727a373 in objc_msg_lookup () at /lib/i386-linux-gnu/libobjc.so.4
> #1  0xafb11ef6 in -[ADPersonView calcSize]
>    (self=0xafb3f4f2 <-[VCFViewer initWithFrame:inspector:]+738>, _cmd=0x5f4020) at ADPersonView.m:325
> #2  0x005ec280 in  ()
> 
> This shows a corrupt stack as in your case, but it's different
> (perhaps because this is a a pure bookworm system +
> GNUstep/GWworkspace built from tarballs +
> src:addresses-for-gnustep/0.4.8-5 with all patches applied built and
> installed in the USER domain along with the rest of GNUstep core).
> 
> The code that corrupts the stack and confuses GDB is line 317 in
> Framework/AddressView/ADPersonView.m:
> 
>     sizeNeeded = [[self superview] frame].size;
> 
> [self superview] returns nil for me (checked at runtime with GDB)
> which leads to a garbage value and the subsequent crash.  The trouble
> is that I don't understand why it happens, and why this occurs on i386
> (and probably other 32-bit arches).  Fred is probably the only person
> in the world who can explain this...  NSView is a fairly complex
> class, and its internals have always been mystery to me.
> 
> Please test the attached patch (it solves the problem for me):
> 
> $ apt-get source addresses-for-gnustep && cd addresses-for-gnustep-*
> (Make sure it's 0.4.8-5; the trixie/sid version)
> $ cp /path/to/1087735.patch debian/patches
> $ echo 1087735.patch >> debian/patches/series
> # apt-get build-dep addresses-for-gnustep
> $ dpkg-buildpackage -us -uc
> # dpkg -i ../libaddressview0_0.4.8-5_i386.deb
> 
> Then start GWorkspace to test.
> 
>> Unless i am not utterly mistaken, then the debugging should probably
>> rather continue with 'addresses-for-gnustep'.
> 
> That's right, I have reassigned the bug.  Many thanks for your
> assistance, we are definitely getting closer to nailing this down.
-------------- next part --------------
--- addresses-for-gnustep-0.4.8.orig/Frameworks/AddressView/ADPersonView.m
+++ addresses-for-gnustep-0.4.8/Frameworks/AddressView/ADPersonView.m
@@ -312,7 +312,7 @@ static NSString *__defaultCountryCode =
   NSSize sizeNeeded;
   NSSize nvSize, nvMaxSize, nvMinSize;

-  if(_fillsSuperview)
+  if(_fillsSuperview && [self superview])
     {
       sizeNeeded = [[self superview] frame].size;
       if (sizeNeeded.width > 10)
-------------- next part --------------