Ticket #14786: 14786_fix_with_tests.diff

django/db/models/fields/__init__.py

@@ -304 +304 @@
         "Returns field's value prepared for database lookup."
         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/tests.py

@@ -8 +8 @@
 from django.db.models.fields.files import FieldFile
 from django.utils import unittest
 
-from models import Foo, Bar, Whiz, BigD, BigS, Image, BigInt, Post, NullBooleanModel, BooleanModel, Document
+from models import (Foo, Bar, Whiz, BigD, BigS, Image, BigInt, Post,
+                    NullBooleanModel, BooleanModel, Document, Base64TextField)
 
 # If PIL available, do these tests.
 if Image:
@@ -348 +349 @@
         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 prepped twice.
+        """
+        # 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
+        self.assertEqual(
+            Base64TextField().get_db_prep_lookup('exact',
+                                                 'test',
+                                                 connection=connection,
+                                                 prepared=False),
+            ['dGVzdA==\n'])
+

tests/regressiontests/model_fields/models.py

@@ -158 +158 @@
                                   width_field='headshot_width')
 
 ###############################################################################
+# Custom field
+
+class Base64TextField(models.TextField):
+    def get_prep_value(self, value):
+        if value is None:
+            return value
+        return super(Base64TextField, self).get_prep_value(value).encode('base64')
+
+
+###############################################################################