bug#23462: 25.0.93; Crash on OS X when suspending main frame

[Ivan Cibrario Bertolotti]

Hi Anders,

> On 10 May 2016, at 20:56, Anders Lindgren <andlind@gmail.com> wrote:
> 
> Hi Ivan and Alan!
> 
> I'm not sure that is the correct place for the patch.
> 
> Could you enable NSTRACE (by uncommenting the line defining NSTRACE_ENABLED 
> in nsterm.h) and see which function calls `drawRect` (if possible). If that 
> is in a function that is part of Emacs, it's better to check that the frame 
> is visible higher up in the call chain.
> 
> You will have to start Emacs from a terminal window in order to see the trace 
> output. You can do this by running "./nextstep/Emacs.app/Content/MacOS/Emacs”.

here is the relevant part of the trace output:

nsterm.m  : 1595: [ 6322]  x_iconify_frame
nsterm.m  : 6770: [ 6323]  | [EmacsView windowWillMiniaturize:]
nsterm.m  : 6735: [ 6324]  | [EmacsView windowDidResignKey:]
nsterm.m  : 1504: [ 6325]  | | ns_frame_rehighlight
nsterm.m  : 7121: [ 6326]  | [EmacsView windowDidMiniaturize:]
nsterm.m  : 7591: [ 6327]  | [EmacsView drawRect:(X:578 Y:4)/(W:15 H:472)]

If I understand it correctly, the top-level function involved (within nsterm.m) 
is x_iconify_frame.  The only explicit call pertinent to the issue that I see 
within it is:

[[view window] miniaturize: NSApp];

at nsterm.m:1615.  I think that the others, from windowWillMiniaturize to 
drawRect, are callbacks.  The reason why a miniaturize request triggers a 
drawRect escapes me at this time, but I’m definitely not an expert on this GUI.

Thank you and please let me know if I can be of further assistance.

Best regards,
Ivan