cssvalue: Handle named colors not resolving

If a named color references a nonexistant named color, we didn't catch
that error and ended up crashing on a NULL-dereference.
This crashed Boxes, because its CSS referenced values from the theme
that didn't exist in any theme.

diff --git a/gtk/gtkcsscolorvalue.c b/gtk/gtkcsscolorvalue.c
index 9ff0a052107e20c605cd48ce675e2967564a0698..64933bde585a7086ec19f70794e8327e65d1d036 100644 (file)
--- a/gtk/gtkcsscolorvalue.c
+++ b/gtk/gtkcsscolorvalue.c
@@ -166,6 +166,8 @@ _gtk_css_color_value_resolve (GtkCssValue             *color,
          return NULL;
 
         value = _gtk_css_color_value_resolve (named, provider, current, current_deps, dependencies);
+       if (value == NULL)
+         return NULL;
       }
 
       break;