dont crack up on entirely unsupported types

diff --git a/lib/sqlalchemy/sql/util.py b/lib/sqlalchemy/sql/util.py
index 06cd78db1dd824860dca5476513faa0d2f2daa8a..0fe9c0c1e926b969df98090682090cecb3fe6a22 100644 (file)
--- a/lib/sqlalchemy/sql/util.py
+++ b/lib/sqlalchemy/sql/util.py
@@ -105,6 +105,9 @@ def determine_date_affinity(expr):
             determine_date_affinity(expr.left), \
             determine_date_affinity(expr.right)
         
+        if left_affin is None or right_affin is None:
+            return None
+            
         if operators.is_commutative(expr.operator):
             key = tuple(sorted([left_affin, right_affin], key=lambda cls:cls.__name__))
         else:

diff --git a/test/dialect/test_postgres.py b/test/dialect/test_postgres.py
index 096a4b8e095a7011f112c9052af2e708641966be..c67ae176cb3079f5b49eb1cea0c9a8f9b3c66aa7 100644 (file)
--- a/test/dialect/test_postgres.py
+++ b/test/dialect/test_postgres.py
@@ -125,6 +125,9 @@ class CompileTest(TestBase, AssertsCompiledSQL):
                 (literal(datetime.timedelta(seconds=10)) - literal(datetime.timedelta(seconds=10)),
                     "(%(param_1)s - %(param_2)s) :: interval"
                 ),
+                (t.c.col3 + "some string", # dont crack up on entirely unsupported types
+                    "t.col3 + %(col3_1)s"
+                )
             ]:
                 self.assert_compile(
                     select([extract(field, expr)]).select_from(t),