.

wcfs/internal/xbtree.py

@@ -410,11 +410,11 @@ def Restructure(ztree, newStructure):
                 # non-empty BTree".
                 zstate = unset = object()
                 if len(node.keyv) == 0:
+                    child = node.children[0]
                     if len(rlevelv) == 2: # only 2 levels
                         assert len(rlevelv[0]) == 1     # top-one has empty tree
                         assert rlevelv[0][0].node is node
-                        child = node.children[0]        # bottom-on has 1 bucket
-                        assert isinstance(child, Bucket)
+                        assert isinstance(child, Bucket)# bottom-on has 1 bucket
                         assert len(rlevelv[1]) == 1
                         assert rlevelv[1][0].node is child
 
@@ -422,10 +422,20 @@ def Restructure(ztree, newStructure):
                         if len(child.keyv) == 0:
                             zstate = None
 
-                        # tree with single bucket withou oid -> tree with embedded bucket
+                        # tree with single bucket without oid -> tree with embedded bucket
                         elif child.Z._p_oid is None:
                             zstate = ((child.Z.__getstate__(),),)
 
+                    # more than 2 levels. For .../T/B B._p_oid must be set - else
+                    # T.__getstate__ will embed B instead of preserving what we
+                    # pass into T.__setstate__
+                    else:
+                        if isinstance(child, Bucket) and child.Z._p_oid is None:
+                            if ztree._p_jar is None:
+                                raise ValueError("Cannot generate .../T/B topology not under ZODB connection")
+                            ztree._p_jar.add(child.Z)
+                            assert child.Z._p_oid is not None
+
                 if zstate is unset:
                     # normal tree node
                     zstate = ()