[pango/pango-1-44: 11/31] layout: Fix a crash

[Matthias Clasen <matthiasc src gnome org>]

commit 800426849efd8a3d1e9d6d26fec3adaa67a50958
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jun 9 11:23:44 2020 -0400

    layout: Fix a crash
    
    pango_layout_get_effective_attributes can return
    NULL. But not all callers were handling that.
    
    (cherry-picked from commit 1f06c915)

 pango/pango-layout.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)
---
diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index 16783941..84dfb39f 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -3031,17 +3031,22 @@ ensure_tab_width (PangoLayout *layout)
       PangoAttribute *attr;
       PangoAttrList *layout_attrs;
       PangoAttrList *tmp_attrs;
-      PangoAttrIterator *iter;
       PangoFontDescription *font_desc = pango_font_description_copy_static 
(pango_context_get_font_description (layout->context));
-      PangoLanguage *language;
+      PangoLanguage *language = NULL;
       PangoShapeFlags shape_flags = PANGO_SHAPE_NONE;
 
       if (pango_context_get_round_glyph_positions (layout->context))
         shape_flags |= PANGO_SHAPE_ROUND_POSITIONS;
 
       layout_attrs = pango_layout_get_effective_attributes (layout);
-      iter = pango_attr_list_get_iterator (layout_attrs);
-      pango_attr_iterator_get_font (iter, font_desc, &language, NULL);
+      if (layout_attrs)
+        {
+          PangoAttrIterator *iter;
+
+          iter = pango_attr_list_get_iterator (layout_attrs);
+          pango_attr_iterator_get_font (iter, font_desc, &language, NULL);
+          pango_attr_iterator_destroy (iter);
+        }
 
       tmp_attrs = pango_attr_list_new ();
 
@@ -3057,7 +3062,6 @@ ensure_tab_width (PangoLayout *layout)
 
       items = pango_itemize (layout->context, " ", 0, 1, tmp_attrs, NULL);
 
-      pango_attr_iterator_destroy (iter);
       if (layout_attrs != layout->attrs)
         {
          pango_attr_list_unref (layout_attrs);