[gtk+/gtk-3-20] icon theme: Add a warning

[Matthias Clasen <matthiasc src gnome org>]

commit 7d2f54f0f3a3d06be919a75bb6f7f03a929555a7
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu May 19 09:03:20 2016 -0400

    icon theme: Add a warning
    
    Warn about the situation when we've found a resource or file path,
    but gdk-pixbuf fails to give us a pixbuf. This generally means that
    either pixbuf loaders are not found or the shared-mime database
    is missing.

 gtk/gtkicontheme.c |   25 ++++++++++++++++++++++++-
 1 files changed, 24 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkicontheme.c b/gtk/gtkicontheme.c
index 4cb4893..8ebf652 100644
--- a/gtk/gtkicontheme.c
+++ b/gtk/gtkicontheme.c
@@ -3951,7 +3951,30 @@ icon_info_ensure_scale_and_pixbuf (GtkIconInfo *icon_info)
     }
 
   if (!source_pixbuf)
-    return FALSE;
+    {
+      static gboolean warn_about_load_failure = TRUE;
+
+      if (warn_about_load_failure)
+        {
+          gchar *path;
+
+          if (icon_info->is_resource)
+            path = g_strdup (icon_info->filename);
+          else if (G_IS_FILE (icon_info->loadable))
+            path = g_file_get_path (G_FILE (icon_info->loadable));
+          else
+            path = g_strdup ("icon theme");
+
+          g_warning ("Could not load a pixbuf from %s.\n"
+                     "This may indicate that pixbuf loaders or the mime database could not be found.",
+                     path);
+          g_free (path);
+
+          warn_about_load_failure = FALSE;
+        }
+
+      return FALSE;
+    }
 
   /* Do scale calculations that depend on the image size
    */