From d075a487c79f73e94414c143ee356e146f0214a8 Mon Sep 17 00:00:00 2001
From: Caleb Rackliffe <calebrackliffe@gmail.com>
Date: Tue, 3 Jun 2014 01:55:00 -0700
Subject: [PATCH] A ModelDefinitionException is now thrown from the metaclass
 at model definition time if the model contains a column whose name conflicts
 with a built-in attribute or method.

(See https://github.com/cqlengine/cqlengine/issues/193)
---
 cqlengine/models.py                 |  7 +++++--
 cqlengine/tests/model/test_model.py | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/cqlengine/models.py b/cqlengine/models.py
index a0df093c..7791da0e 100644
--- a/cqlengine/models.py
+++ b/cqlengine/models.py
@@ -649,9 +649,12 @@ class ModelMetaClass(type):
 
         has_partition_keys = any(v.partition_key for (k, v) in column_definitions)
 
-        #TODO: check that the defined columns don't conflict with any of the Model API's existing attributes/methods
         #transform column definitions
         for k, v in column_definitions:
+            # don't allow a column with the same name as a built-in attribute or method
+            if k in BaseModel.__dict__:
+                raise ModelDefinitionException("column '{}' conflicts with built-in attribute/method".format(k))
+
             # counter column primary keys are not allowed
             if (v.primary_key or v.partition_key) and isinstance(v, (columns.Counter, columns.BaseContainerColumn)):
                 raise ModelDefinitionException('counter columns and container columns cannot be used as primary keys')
@@ -661,7 +664,7 @@ class ModelMetaClass(type):
             if not has_partition_keys and v.primary_key:
                 v.partition_key = True
                 has_partition_keys = True
-            _transform_column(k,v)
+            _transform_column(k, v)
 
         partition_keys = OrderedDict(k for k in primary_keys.items() if k[1].partition_key)
         clustering_keys = OrderedDict(k for k in primary_keys.items() if not k[1].partition_key)
diff --git a/cqlengine/tests/model/test_model.py b/cqlengine/tests/model/test_model.py
index a0a6929a..1e18359e 100644
--- a/cqlengine/tests/model/test_model.py
+++ b/cqlengine/tests/model/test_model.py
@@ -1,6 +1,6 @@
 from unittest import TestCase
 
-from cqlengine.models import Model
+from cqlengine.models import Model, ModelDefinitionException
 from cqlengine import columns
 
 
@@ -31,3 +31,21 @@ class TestModel(TestCase):
 
         self.assertEqual(m0, m0)
         self.assertNotEqual(m0, m1)
+
+
+class BuiltInAttributeConflictTest(TestCase):
+    """tests Model definitions that conflict with built-in attributes/methods"""
+
+    def test_model_with_attribute_name_conflict(self):
+        """should raise exception when model defines column that conflicts with built-in attribute"""
+        with self.assertRaises(ModelDefinitionException):
+            class IllegalTimestampColumnModel(Model):
+                my_primary_key = columns.Integer(primary_key=True)
+                timestamp = columns.BigInt()
+
+    def test_model_with_method_name_conflict(self):
+        """should raise exception when model defines column that conflicts with built-in method"""
+        with self.assertRaises(ModelDefinitionException):
+            class IllegalFilterColumnModel(Model):
+                my_primary_key = columns.Integer(primary_key=True)
+                filter = columns.Text()
\ No newline at end of file