- Fixed potential issue where a custom subclass

of :class:`.FunctionElement` or other column element that incorrectly
states 'None' or any other invalid object as the ``.type``
attribute will report this exception instead of recursion overflow.
fixes #3485

1 files changed, 14 insertions, 2 deletions

diff --git a/test/sql/test_functions.py b/test/sql/test_functions.py
index ec8d9b5c0..ccc9b2dcd 100644
--- a/test/sql/test_functions.py
+++ b/test/sql/test_functions.py
@@ -9,12 +9,12 @@ from sqlalchemy.sql.compiler import BIND_TEMPLATES
 from sqlalchemy.testing.engines import all_dialects
 from sqlalchemy import types as sqltypes
 from sqlalchemy.sql import functions
-from sqlalchemy.sql.functions import GenericFunction
+from sqlalchemy.sql.functions import GenericFunction, FunctionElement
 import decimal
 from sqlalchemy import testing
 from sqlalchemy.testing import fixtures, AssertsCompiledSQL, engines
 from sqlalchemy.dialects import sqlite, postgresql, mysql, oracle
-
+from sqlalchemy.testing import assert_raises_message
 
 table1 = table('mytable',
                column('myid', Integer),
@@ -477,6 +477,18 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
             "AS anon_1 FROM mytable"
         )
 
+    def test_incorrect_none_type(self):
+        class MissingType(FunctionElement):
+            name = 'mt'
+            type = None
+
+        assert_raises_message(
+            TypeError,
+            "Object None associated with '.type' attribute is "
+            "not a TypeEngine class or object",
+            MissingType().compile
+        )
+
 
 class ExecuteTest(fixtures.TestBase):