suppress warning when closing second document

diff --git a/src/document-subset.cpp b/src/document-subset.cpp
index 5fcf1641cf80d26052816317ed244686e845bcd6..04b3d9b0629cdc22965e88bb1cc0ef185b121b1e 100644 (file)
--- a/src/document-subset.cpp
+++ b/src/document-subset.cpp
@@ -140,7 +140,8 @@ struct DocumentSubset::Relations : public GC::Managed<GC::ATOMIC>,
         for ( Map::iterator iter=records.begin()
             ; iter != records.end() ; ++iter )
         {
-            sp_object_unref((*iter).first);
+            if ((*iter).first)
+                sp_object_unref((*iter).first);
         }
     }