.

wcfs/internal/xbtree.py

@@ -828,27 +828,20 @@ def _zclassify(znode): # -> _ZNodeType
 # _bcheck performs full consistency checks on ztree provided by ZODB.
 #
 # The checks are what is provided by BTree.check and node._check().
-
-#class _ZChecker(zbcheck.Checker):
-#    def visit_btree(self, obj, *argv):
-#        #super(_ZChecker, self).visit_btree(obj, *argv)     zbcheck.Checker is old-style class
-#        zbcheck.Checker.visit_btree(self, obj, *argv)
-#        obj._check() # also check internal C-level pointers consistency
-#
-#    # no need to amend visit_bucket - there is no Bucket._check
-#    """
-#    def visit_bucket(self, obj, *argv):
-#        #super(_ZChecker, self).visit_bucket(obj, *argv)
-#        zbcheck.Checker.visit_bucket(self, obj, *argv)
-#        obj._check() # ----//-----
-#    """
-
 def _bcheck(ztree):
-    #_ZChecker(ztree).check()
-    # verify internal C-level pointers consistency (valid to call only on root node)
+    # verify internal C-level pointers consistency.
+    #
+    # Only valid to be called on root node and verifies whole tree.
+    # If called on a non-root node will lead to assert "Bucket next pointer is
+    # damaged" since it calls BTree_check_inner(ztree, next_bucket=nil)
+    # assuming ztree is a root tree node, and its rightmost bucket should
+    # indeed have ->next=nil. If ztree is not root, there can be right-adjacent
+    # part of the tree, to which ztree's rightmost bucket must be linking to
+    # via its ->next.
     ztree._check()
-    zbcheck.check(ztree)    # verify nodes values consistency
 
+    # verify nodes values consistency
+    zbcheck.check(ztree)