Fix crash when unlinking orphaned clones. Patch from Adonis Papaderos.

Fixed bugs:
  - https://launchpad.net/bugs/675309

(bzr r9922)

2 files changed, 6 insertions, 1 deletions

diff --git a/src/selection-chemistry.cpp b/src/selection-chemistry.cpp
index 61db7f961..6786479d6 100644
--- a/src/selection-chemistry.cpp
+++ b/src/selection-chemistry.cpp
@@ -2150,6 +2150,11 @@ sp_selection_unlink(SPDesktop *desktop)
         SPItem *unlink;
         if (SP_IS_USE(item)) {
             unlink = sp_use_unlink(SP_USE(item));
+            // Unable to unlink use (external or invalid href?)
+            if (!unlink) {
+                new_select = g_slist_prepend(new_select, item);
+                continue;
+            }
         } else /*if (SP_IS_TREF(use))*/ {
             unlink = SP_ITEM(sp_tref_convert_to_tspan(item));
         }
diff --git a/src/sp-use.cpp b/src/sp-use.cpp
index 9cd38e4b3..ecb7eb788 100644
--- a/src/sp-use.cpp
+++ b/src/sp-use.cpp
@@ -678,7 +678,7 @@ sp_use_unlink(SPUse *use)
 
     // Track the ultimate source of a chain of uses.
     SPItem *orig = sp_use_root(use);
-    g_return_val_if_fail(orig, NULL);
+    if (!orig) return NULL ;
 
     // Calculate the accumulated transform, starting from the original.
     Geom::Matrix t = sp_use_get_root_transform(use);