One thing to note: I have tested with Wayland. Please see the attachment
for a backtrace.
0x00007ffff72c67ee in _XGetRequest (dpy=dpy@entry=0x555555577930,
type=type@entry=98 'b', len=len@entry=8)
at ../../src/XlibInt.c:1796
⚠️ warning: 1796 ../../src/XlibInt.c: No such file or directory
(gdb) bt
#0 0x00007ffff72c67ee in _XGetRequest (dpy=dpy@entry=0x555555577930,
type=type@entry=98 'b', len=len@entry=8)
at ../../src/XlibInt.c:1796
#1 0x00007ffff72b8f82 in XQueryExtension
(dpy=dpy@entry=0x555555577930, name=name@entry=0x7ffff66ca250
<XRenderExtensionName> "RENDER",
major_opcode=major_opcode@entry=0x7fffffffd7b4,
first_event=first_event@entry=0x7fffffffd7b8,
first_error=first_error@entry=0x7fffffffd7bc) at ../../src/QuExt.c:49
#2 0x00007ffff72aba14 in XInitExtension
(dpy=dpy@entry=0x555555577930, name=name@entry=0x7ffff66ca250
<XRenderExtensionName> "RENDER") at ../../src/InitExt.c:59
#3 0x00007ffff66c5469 in XRenderExtAddDisplay
(extinfo=0x7ffff66ca270 <XRenderExtensionInfo>, ext_name=0x7ffff66ca250
<XRenderExtensionName> "RENDER", dpy=0x555555577930)
at ../../src/Xrender.c:206
#4 XRenderFindDisplay (dpy=0x555555577930) at ../../src/Xrender.c:292
#5 XRenderFindDisplay (dpy=0x555555577930) at ../../src/Xrender.c:286
#6 0x00007ffff66c57d5 in XRenderQueryExtension
(dpy=dpy@entry=0x555555577930,
event_basep=event_basep@entry=0x7fffffffd8b4,
error_basep=error_basep@entry=0x7fffffffd8b8)
at ../../src/Xrender.c:324
#7 0x00007ffff73ce79a in _XftDisplayInfoGet (dpy=0x555555577930,
createIfNecessary=<optimized out>) at ../../src/xftdpy.c:102
#8 _XftDisplayInfoGet (dpy=0x555555577930, createIfNecessary=<optimized out>)
at ../../src/xftdpy.c:65
#9 0x00007ffff73ced72 in XftDefaultHasRender (dpy=dpy@entry=0x555555577930) at
../../src/xftdpy.c:268
#10 0x00007ffff73cf220 in XftDefaultSubstitute
(dpy=dpy@entry=0x555555577930, screen=screen@entry=1431839360,
pattern=pattern@entry=0x5555557c1590) at ../../src/xftdpy.c:489
#11 0x00007ffff73d1d8d in XftFontMatch
(dpy=0x555555577930, screen=screen@entry=1431839360,
pattern=pattern@entry=0x5555557c1f00, result=result@entry=0x7fffffffd9f4)
at ../../src/xftfont.c:52
#12 0x0000555555558bbe in open_font (waterfall=waterfall@entry=0x55555569d1f0
[Waterfall], size=5) at ./src/waterfall.c:87
#13 0x000055555555973f in waterfall_set_font_family
(waterfall=waterfall@entry=0x55555569d1f0 [Waterfall],
new_family=new_family@entry=0x5555557c1ee0 "DejaVu Sans")
at ./src/waterfall.c:363
#14 0x0000555555558630 in family_changed (combo=<optimized out>,
waterfall=0x55555569d1f0 [Waterfall]) at ./src/main.c:80
#18 0x00007ffff76bf4e3 in <emit signal 'changed' on instance 0x555555700830
[GtkComboBoxText]>
(instance=instance@entry=0x555555700830, signal_id=<optimized out>,
detail=detail@entry=0) at ../../../gobject/gsignal.c:3598
#15 0x00007ffff76a2c71 in _g_closure_invoke_va
(closure=closure@entry=0x5555557af2a0, return_value=return_value@entry=0x0,
instance=instance@entry=0x555555700830, args=args@entry=0x7fffffffdd20,
n_params=n_params@entry=0, param_types=param_types@entry=0x0) at
../../../gobject/gclosure.c:980
#16 0x00007ffff76b9978 in signal_emit_valist_unlocked
(instance=instance@entry=0x555555700830, signal_id=signal_id@entry=224,
detail=detail@entry=0, var_args=var_args@entry=0x7fffffffdd20) at
../../../gobject/gsignal.c:3439
#17 0x00007ffff76bf428 in g_signal_emit_valist (instance=0x555555700830,
signal_id=224, detail=0, var_args=0x7fffffffdd20)
at ../../../gobject/gsignal.c:3278
#19 0x00007ffff7916d3d in gtk_combo_box_set_active_internal
(combo_box=combo_box@entry=0x555555700830 [GtkComboBoxText],
path=path@entry=0x5555557c0330) at ../../../gtk/gtkcombobox.c:3855
#20 0x00007ffff791982c in gtk_combo_box_set_active (combo_box=0x555555700830
[GtkComboBoxText], index_=0)
at ../../../gtk/gtkcombobox.c:3779
#21 gtk_combo_box_set_active (combo_box=combo_box@entry=0x555555700830
[GtkComboBoxText], index_=index_@entry=0)
at ../../../gtk/gtkcombobox.c:3757
#22 0x000055555555799e in construct_font_family_chooser
(waterfall=0x55555569d1f0 [Waterfall]) at ./src/main.c:142
#23 construct_options_bar (waterfall=0x55555569d1f0 [Waterfall]) at
./src/main.c:535
#24 main (argc=<optimized out>, argv=<optimized out>) at ./src/main.c:651
(gdb) bt
#0 0x00007ffff72c67ee in _XGetRequest (dpy=dpy@entry=0x555555577930,
type=type@entry=98 'b', len=len@entry=8) at ../../src/XlibInt.c:1796
#1 0x00007ffff72b8f82 in XQueryExtension
(dpy=dpy@entry=0x555555577930, name=name@entry=0x7ffff66ca250
<XRenderExtensionName> "RENDER",
major_opcode=major_opcode@entry=0x7fffffffd7b4,
first_event=first_event@entry=0x7fffffffd7b8,
first_error=first_error@entry=0x7fffffffd7bc) at ../../src/QuExt.c:49
#2 0x00007ffff72aba14 in XInitExtension (dpy=dpy@entry=0x555555577930,
name=name@entry=0x7ffff66ca250 <XRenderExtensionName> "RENDER") at
../../src/InitExt.c:59
#3 0x00007ffff66c5469 in XRenderExtAddDisplay (extinfo=0x7ffff66ca270
<XRenderExtensionInfo>, ext_name=0x7ffff66ca250 <XRenderExtensionName>
"RENDER", dpy=0x555555577930) at ../../src/Xrender.c:206
#4 XRenderFindDisplay (dpy=0x555555577930) at ../../src/Xrender.c:292
#5 XRenderFindDisplay (dpy=0x555555577930) at ../../src/Xrender.c:286
#6 0x00007ffff66c57d5 in XRenderQueryExtension (dpy=dpy@entry=0x555555577930,
event_basep=event_basep@entry=0x7fffffffd8b4,
error_basep=error_basep@entry=0x7fffffffd8b8) at ../../src/Xrender.c:324
#7 0x00007ffff73ce79a in _XftDisplayInfoGet (dpy=0x555555577930,
createIfNecessary=<optimized out>) at ../../src/xftdpy.c:102
#8 _XftDisplayInfoGet (dpy=0x555555577930, createIfNecessary=<optimized out>)
at ../../src/xftdpy.c:65
#9 0x00007ffff73ced72 in XftDefaultHasRender (dpy=dpy@entry=0x555555577930) at
../../src/xftdpy.c:268
#10 0x00007ffff73cf220 in XftDefaultSubstitute (dpy=dpy@entry=0x555555577930,
screen=screen@entry=1431839360, pattern=pattern@entry=0x5555557c1590) at
../../src/xftdpy.c:489
#11 0x00007ffff73d1d8d in XftFontMatch (dpy=0x555555577930,
screen=screen@entry=1431839360, pattern=pattern@entry=0x5555557c1f00,
result=result@entry=0x7fffffffd9f4) at ../../src/xftfont.c:52
#12 0x0000555555558bbe in open_font (waterfall=waterfall@entry=0x55555569d1f0
[Waterfall], size=5) at ./src/waterfall.c:87
#13 0x000055555555973f in waterfall_set_font_family
(waterfall=waterfall@entry=0x55555569d1f0 [Waterfall],
new_family=new_family@entry=0x5555557c1ee0 "DejaVu Sans") at
./src/waterfall.c:363
#14 0x0000555555558630 in family_changed (combo=<optimized out>,
waterfall=0x55555569d1f0 [Waterfall]) at ./src/main.c:80
#18 0x00007ffff76bf4e3 in <emit signal 'changed' on instance 0x555555700830
[GtkComboBoxText]> (instance=instance@entry=0x555555700830,
signal_id=<optimized out>, detail=detail@entry=0) at
../../../gobject/gsignal.c:3598
#15 0x00007ffff76a2c71 in _g_closure_invoke_va
(closure=closure@entry=0x5555557af2a0, return_value=return_value@entry=0x0,
instance=instance@entry=0x555555700830, args=args@entry=0x7fffffffdd20,
n_params=n_params@entry=0, param_types=param_types@entry=0x0)
at ../../../gobject/gclosure.c:980
#16 0x00007ffff76b9978 in signal_emit_valist_unlocked
(instance=instance@entry=0x555555700830, signal_id=signal_id@entry=224,
detail=detail@entry=0, var_args=var_args@entry=0x7fffffffdd20) at
../../../gobject/gsignal.c:3439
#17 0x00007ffff76bf428 in g_signal_emit_valist (instance=0x555555700830,
signal_id=224, detail=0, var_args=0x7fffffffdd20) at
../../../gobject/gsignal.c:3278
#19 0x00007ffff7916d3d in gtk_combo_box_set_active_internal
(combo_box=combo_box@entry=0x555555700830 [GtkComboBoxText],
path=path@entry=0x5555557c0330) at ../../../gtk/gtkcombobox.c:3855
#20 0x00007ffff791982c in gtk_combo_box_set_active (combo_box=0x555555700830
[GtkComboBoxText], index_=0) at ../../../gtk/gtkcombobox.c:3779
#21 gtk_combo_box_set_active (combo_box=combo_box@entry=0x555555700830
[GtkComboBoxText], index_=index_@entry=0) at ../../../gtk/gtkcombobox.c:3757
#22 0x000055555555799e in construct_font_family_chooser
(waterfall=0x55555569d1f0 [Waterfall]) at ./src/main.c:142
#23 construct_options_bar (waterfall=0x55555569d1f0 [Waterfall]) at
./src/main.c:535
#24 main (argc=<optimized out>, argv=<optimized out>) at ./src/main.c:651
