diff options
Diffstat (limited to 'lib/sqlalchemy/sql/visitors.py')
| -rw-r--r-- | lib/sqlalchemy/sql/visitors.py | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py index 9bc5d2479..1a0629a17 100644 --- a/lib/sqlalchemy/sql/visitors.py +++ b/lib/sqlalchemy/sql/visitors.py @@ -47,10 +47,19 @@ class ClauseVisitor(object): traversal.insert(0, t) for c in t.get_children(**self.__traverse_options__): stack.append(c) - + def traverse(self, obj, stop_on=None, clone=False): + if clone: - obj = obj._clone() + cloned = {} + def do_clone(obj): + # the full traversal will only make a clone of a particular element + # once. + if obj not in cloned: + cloned[obj] = obj._clone() + return cloned[obj] + + obj = do_clone(obj) stack = [obj] traversal = [] @@ -59,7 +68,7 @@ class ClauseVisitor(object): if stop_on is None or t not in stop_on: traversal.insert(0, t) if clone: - t._copy_internals() + t._copy_internals(clone=do_clone) for c in t.get_children(**self.__traverse_options__): stack.append(c) for target in traversal: |