bug#35204: 27.0.50; Crash on Cygwin

["Basil L. Contovounesios" <contovob@tcd.ie>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Ken Brown <kbrown@cornell.edu>
>> CC: "35204@debbugs.gnu.org" <35204@debbugs.gnu.org>
>> Date: Fri, 12 Apr 2019 14:54:21 +0000
>> 
>> I can replicate the crash on my system, but reverting only a tiny part of the 
>> commits in question seems to fix it, in the sense that I can successfully 
>> evaluate x-display-monitor-attributes-list:
>> 
>> diff --git a/src/xfns.c b/src/xfns.c
>> index 13f66f0718..3e4d037716 100644
>> --- a/src/xfns.c
>> +++ b/src/xfns.c
>> @@ -5030,7 +5030,7 @@ Internal use only, use `display-monitor-attributes-list' 
>> instead.  */)
>>         mi->mm_height = height_mm;
>> 
>>   #if GTK_CHECK_VERSION (3, 22, 0)
>> -      mi->name = xstrdup (gdk_monitor_get_model (monitor));
>> +      mi->name = g_strdup (gdk_monitor_get_model (monitor));
>>   #elif GTK_CHECK_VERSION (2, 14, 0)
>>         mi->name = gdk_screen_get_monitor_plug_name (gscreen, i);
>>   #endif
>> 
>> I don't know enough about GTK to know why this fixes it or why no one else has 
>> reported the problem.  It's hard to see why this would be specific to Cygwin.
>
> We release storage of mi->name (in free_monitors) by calling xfree, so
> I'm surprised g_strdup is right here, as that is documented to need
> g_free instead.  I wonder what am I missing.

I think the missing clue is in bug#35259: gdk_monitor_get_model may
return NULL, which g_strdup gladly accepts, but xstrdup does not.

https://debbugs.gnu.org/35259

-- 
Basil