commit ad92e199f221499c19f22dce7a16e7d770ad3ae7
Author: Carsten Pfeiffer <carsten.pfeiffer@gebit.de>
Date:   Fri Aug 10 16:06:20 2018 +0200

    Fix crash in pango_fc_font_key_get_variations() when key is null

diff --git a/pango/pangofc-shape.c b/pango/pangofc-shape.c
index a59ca67c..53269d73 100644
--- a/pango/pangofc-shape.c
+++ b/pango/pangofc-shape.c
@@ -380,8 +380,10 @@ _pango_fc_shape (PangoFont           *font,
 		    fc_font->is_hinted ? ft_face->size->metrics.x_ppem : 0,
 		    fc_font->is_hinted ? ft_face->size->metrics.y_ppem : 0);
 
-  variations = pango_fc_font_key_get_variations (key);
-  if (variations)
+  if (key)
+  {
+    variations = pango_fc_font_key_get_variations (key);
+    if (variations)
     {
       guint n_variations;
       hb_variation_t *hb_variations;
@@ -391,6 +393,7 @@ _pango_fc_shape (PangoFont           *font,
 
       g_free (hb_variations);
     }
+  }
 
   hb_buffer = acquire_buffer (&free_buffer);