[gnome-builder] xml pack: fix possible use of a NULL pointer

[Sébastien Lafargue <slafargue src gnome org>]

commit 7a44366cec91fbd0e856f1eaa818eacb15b8fd2a
Author: Sebastien Lafargue <slafargue gnome org>
Date:   Mon Aug 14 23:17:52 2017 +0200

    xml pack: fix possible use of a NULL pointer

 plugins/xml-pack/ide-xml-position.c |   31 +++++++++++++++++--------------
 1 files changed, 17 insertions(+), 14 deletions(-)
---
diff --git a/plugins/xml-pack/ide-xml-position.c b/plugins/xml-pack/ide-xml-position.c
index d4cf854..e206c31 100644
--- a/plugins/xml-pack/ide-xml-position.c
+++ b/plugins/xml-pack/ide-xml-position.c
@@ -273,23 +273,26 @@ ide_xml_position_print (IdeXmlPosition *self)
   if (self->child_pos != -1)
     {
       printf (" (between %s and %s)", p_sibling_str, n_sibling_str);
-      n_children = ide_xml_symbol_node_get_n_direct_children (self->node);
-      if (self->child_pos == 0)
+      if (self->node != NULL)
         {
-          if (n_children == 1)
-            printf (" pos: |0\n");
-          else
-            printf (" pos: |0..%d\n", n_children - 1);
-        }
-      else if (self->child_pos == n_children)
-        {
-          if (n_children == 1)
-            printf (" pos: 0|\n");
+          n_children = ide_xml_symbol_node_get_n_direct_children (self->node);
+          if (self->child_pos == 0)
+            {
+              if (n_children == 1)
+                printf (" pos: |0\n");
+              else
+                printf (" pos: |0..%d\n", n_children - 1);
+            }
+          else if (self->child_pos == n_children)
+            {
+              if (n_children == 1)
+                printf (" pos: 0|\n");
+              else
+                printf (" pos: 0..%d|\n", n_children - 1);
+            }
           else
-            printf (" pos: 0..%d|\n", n_children - 1);
+            printf (" pos: %d|%d\n", self->child_pos - 1, self->child_pos);
         }
-      else
-        printf (" pos: %d|%d\n", self->child_pos - 1, self->child_pos);
     }
   else if (self->child_node != NULL)
     printf (" child node:%s\n", ide_xml_symbol_node_get_element_name (self->child_node));