Accommodate "callable" bound param in evaluator

Fixed bug in "evaluate" strategy of :meth:`.Query.update` and
:meth:`.Query.delete` which would fail to accommodate a bound
parameter with a "callable" value, as which occurs when filtering
by a many-to-one equality expression along a relationship.

Change-Id: I47758d3f5d8b9ea1a07e23166780d5f3c32b17f1
Fixes: #3700

1 files changed, 13 insertions, 1 deletions

diff --git a/test/orm/test_evaluator.py b/test/orm/test_evaluator.py
index bafe17b2c..9aae8dd34 100644
--- a/test/orm/test_evaluator.py
+++ b/test/orm/test_evaluator.py
@@ -1,6 +1,6 @@
 """Evaluating SQL expressions on ORM objects"""
 
-from sqlalchemy import String, Integer
+from sqlalchemy import String, Integer, bindparam
 from sqlalchemy.testing.schema import Table
 from sqlalchemy.testing.schema import Column
 from sqlalchemy.testing import fixtures
@@ -58,6 +58,18 @@ class EvaluateTest(fixtures.MappedTest):
             (User(id=None), None),
         ])
 
+    def test_compare_to_callable_bind(self):
+        User = self.classes.User
+
+        eval_eq(
+            User.name == bindparam('x', callable_=lambda: 'foo'),
+            testcases=[
+                (User(name='foo'), True),
+                (User(name='bar'), False),
+                (User(name=None), None),
+            ]
+        )
+
     def test_compare_to_none(self):
         User = self.classes.User