[glib] gio: Check for NUll when getting extensions

[Philip Withnall <pwithnall src gnome org>]

commit 1a845115a24bea553885acb69b731dbc32d3369b
Author: Jan Tojnar <jtojnar gmail com>
Date:   Fri Feb 24 16:46:55 2017 +0100

    gio: Check for NUll when getting extensions
    
    When unregistered extension point (i.e. NULL pointer) is passed
    to `g_io_extension_point_get_extensions`, it causes a segfault.
    
    This commit adds an assertion, to prevent this.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=779183

 gio/giomodule.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gio/giomodule.c b/gio/giomodule.c
index 29a9f09..6bb8203 100644
--- a/gio/giomodule.c
+++ b/gio/giomodule.c
@@ -1280,6 +1280,8 @@ lazy_load_modules (GIOExtensionPoint *extension_point)
 GList *
 g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point)
 {
+  g_return_val_if_fail (extension_point != NULL, NULL);
+
   lazy_load_modules (extension_point);
   return extension_point->extensions;
 }