.

wcfs/internal/xbtree.py

@@ -311,7 +311,9 @@ def Restructure(ztree, newStructure):
         if len(RZv) == len(RNv):
             # assert the result is 1-1 mapping
             for j in range(len(RNv)):
-                assert RNv[j].node.Z is RZv[j].node
+                if RNv[j].node.Z is not RZv[j].node:
+                    panic("BUG: Restructure %s -> %s: assign: not 1-1 mapping:\n RZv: %s\nRNv: %s" %
+                            (TopoEncode(StructureOf(ztree)), TopoEncode(newStructure), RZv, RNv))
 
         # XXX assert assignments are in key↑ order ?