bug#30874: 27.0.50; Emacs crashes

[Robert Pluim]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Robert Pluim <rpluim@gmail.com>
>> Cc: 30874@debbugs.gnu.org,  jsynacek@redhat.com
>> Date: Sat, 31 Mar 2018 15:55:13 +0200
>> 
>> Iʼm testing the following, which fixes the 20890 crash for me when
>> using Cairo.
>> 
>> diff --git i/src/ftfont.c w/src/ftfont.c
>> index c2e093e633..89c07e1f21 100644
>> --- i/src/ftfont.c
>> +++ w/src/ftfont.c
>> @@ -1242,6 +1242,11 @@ ftfont_close (struct font *font)
>>    struct ftfont_info *ftfont_info = (struct ftfont_info *) font;
>>    Lisp_Object val, cache;
>>  
>> +#ifdef USE_CAIRO
>> +  /* Bug#20890 workaround.  */
>> +  if (gc_in_progress)
>> +    return;
>> +#endif
>>    val = Fcons (font->props[FONT_FILE_INDEX], make_number 
>> (ftfont_info->index));
>>    cache = ftfont_lookup_cache (val, FTFONT_CACHE_FOR_FACE);
>>    eassert (CONSP (cache));
>
> This LGTM, thanks.
>

Iʼll follow up in bug 20890.

>
> It can stay in ftfont.c, but please make the second hunk
> unconditional, so that the variable is known and available in all the
> builds, just say in the doc string that this variable has effect only
> on the xftfont backend.  I have bad experience with variables that are
> only defined in some configurations: it means both trouble for users
> who use more than one configuration and more maintenance headaches.
> Come to think of it, maybe it's best to move DEFVAR_BOOL to font.c,
> for that very reason.

OK, adjusted accordingly.

Robert