- Fixed issue where inadvertent use of the Python ``__contains__``

override with a column expression (e.g. by using ``'x' in col``)
would cause an endless loop in the case of an ARRAY type, as Python
defers this to ``__getitem__`` access which never raises for this
type.  Overall, all use of ``__contains__`` now raises
NotImplementedError.
fixes #3642

2 files changed, 5 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/default_comparator.py b/lib/sqlalchemy/sql/default_comparator.py
index 6c8e69dee..1bb1c344c 100644
--- a/lib/sqlalchemy/sql/default_comparator.py
+++ b/lib/sqlalchemy/sql/default_comparator.py
@@ -274,6 +274,7 @@ operator_lookup = {
     "getitem": (_getitem_impl,),
     "lshift": (_unsupported_impl,),
     "rshift": (_unsupported_impl,),
+    "contains": (_unsupported_impl,),
 }
 
 
diff --git a/lib/sqlalchemy/sql/operators.py b/lib/sqlalchemy/sql/operators.py
index ba1d0f65e..80f08a97c 100644
--- a/lib/sqlalchemy/sql/operators.py
+++ b/lib/sqlalchemy/sql/operators.py
@@ -14,7 +14,7 @@ from .. import util
 
 from operator import (
     and_, or_, inv, add, mul, sub, mod, truediv, lt, le, ne, gt, ge, eq, neg,
-    getitem, lshift, rshift
+    getitem, lshift, rshift, contains
 )
 
 if util.py2k:
@@ -335,6 +335,9 @@ class ColumnOperators(Operators):
         """
         return self.operate(neg)
 
+    def __contains__(self, other):
+        return self.operate(contains, other)
+
     def __getitem__(self, index):
         """Implement the [] operator.