Refs #2443 -- Allowed creation of objects with NULL DurationFields

django/db/models/fields/__init__.py

@@ -1651,6 +1651,8 @@ class DurationField(Field):
     def get_db_prep_value(self, value, connection, prepared=False):
         if connection.features.has_native_duration_field:
             return value
+        if value is None:
+            return None
         return value.total_seconds() * 1000000
 
     def get_db_converters(self, connection):

tests/model_fields/models.py

@@ -129,6 +129,10 @@ class DurationModel(models.Model):
     field = models.DurationField()
 
 
+class NullDurationModel(models.Model):
+    field = models.DurationField(null=True)
+
+
 class PrimaryKeyCharModel(models.Model):
     string = models.CharField(max_length=10, primary_key=True)
 

tests/model_fields/test_durationfield.py

@@ -5,7 +5,7 @@ from django.core import exceptions, serializers
 from django.db import models
 from django.test import TestCase
 
-from .models import DurationModel
+from .models import DurationModel, NullDurationModel
 
 
 class TestSaveLoad(TestCase):
@@ -16,6 +16,11 @@ class TestSaveLoad(TestCase):
         loaded = DurationModel.objects.get()
         self.assertEqual(loaded.field, duration)
 
+    def test_create_empty(self):
+        NullDurationModel.objects.create()
+        loaded = NullDurationModel.objects.get()
+        self.assertEqual(loaded.field, None)
+
 
 class TestQuerying(TestCase):