- add a type_coerce() step within Enum, Boolean to the CHECK constraint,

so that the custom type isn't exposed to an operation that is against the
"impl" type's constraint, [ticket:2842]
- this change showed up as some recursion overflow in pickling with labels,
add a __reduce__() there....pickling of expressions is less and less something
that's very viable...

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 2688ef103..f70496418 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -1842,6 +1842,9 @@ class Label(ColumnElement):
         self._type = type_
         self._proxies = [element]
 
+    def __reduce__(self):
+        return self.__class__, (self.name, self._element, self._type)
+
     @util.memoized_property
     def _order_by_label_element(self):
         return self