Add with_for_update() support in session.refresh()

Session.refresh() is still hardcoded to legacy lockmode,
come up with a new API so that the newer argument style
works with it.

Added new argument :paramref:`.with_for_update` to the
:meth:`.Session.refresh` method.  When the :meth:`.Query.with_lockmode`
method were deprecated in favor of :meth:`.Query.with_for_update`,
the :meth:`.Session.refresh` method was never updated to reflect
the new option.

Change-Id: Ia02a653746b7024699b515451525a88d7a17d63a
Fixes: #3991

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index a6ed6b0ce..a1e3abcb4 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -1841,6 +1841,19 @@ class ForUpdateArg(ClauseElement):
         else:
             return True
 
+    def __eq__(self, other):
+        return (
+            isinstance(other, ForUpdateArg) and
+            other.nowait == self.nowait and
+            other.read == self.read and
+            other.skip_locked == self.skip_locked and
+            other.key_share == self.key_share and
+            other.of is self.of
+        )
+
+    def __hash__(self):
+        return id(self)
+
     def _copy_internals(self, clone=_clone, **kw):
         if self.of is not None:
             self.of = [clone(col, **kw) for col in self.of]