Ticket #14786: ticket14786.diff

django/db/models/fields/__init__.py

@@ -326 +326 @@
         """
         if not prepared:
             value = self.get_prep_lookup(lookup_type, value)
+            prepared = True
         if hasattr(value, 'get_compiler'):
             value = value.get_compiler(connection=connection)
         if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):

tests/regressiontests/model_fields/models.py

@@ -163 +163 @@
         headshot = TestImageField(blank=True, null=True,
                                   storage=temp_storage, upload_to='tests',
                                   height_field='headshot_height',
-                                  width_field='headshot_width')
-
-###############################################################################
+                                  width_field='headshot_width')
+ No newline at end of file

tests/regressiontests/model_fields/tests.py

@@ -365 +365 @@
         field = d._meta.get_field('myfile')
         field.save_form_data(d, 'else.txt')
         self.assertEqual(d.myfile, 'else.txt')
+
+
+class CustomFieldTests(unittest.TestCase):
+
+    def test_14786(self):
+        """
+        Test that field values are not prepared twice.
+        """
+        prepare_count = [0]
+        class NoopField(models.TextField):
+            def get_prep_value(self, value):
+                prepare_count[0] += 1
+                return super(NoopField, self).get_prep_value(value).encode('base64')
+
+        # Regression test for #14786. When get_db_prep_lookup is called with
+        # prepared = False, the value is passed through get_prep_value twice.
+        from django.db import connection
+        field = NoopField()
+        field.get_db_prep_lookup('exact', 'TEST', connection=connection, prepared=False)
+        self.assertEqual(prepare_count[0], 1)