Merge pull request #153 from rubendura/master

Enables support for primary keys that are not AutoFields.

.gitignore

@@ -10,3 +10,5 @@ atlassian-*
 .ropeproject
 .codeintel
 __pycache__
+.venv/
+build

adminsortable/models.py

@@ -1,5 +1,6 @@
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
+from django.utils import version
 
 from adminsortable.fields import SortableForeignKey
 
@@ -87,7 +88,11 @@ class SortableMixin(models.Model):
             'typecast to an integer.'
 
     def save(self, *args, **kwargs):
-        if not self.pk:
+        major, minor, _, _, _ = version.get_complete_version()
+        needs_default = (self._state.adding
+                         if major == 1 and minor >= 8
+                         else not self.pk)
+        if needs_default:
             try:
                 current_max = self.__class__.objects.aggregate(
                     models.Max(self.order_field_name))[self.order_field_name + '__max'] or 0

sample_project/app/tests.py

@@ -4,6 +4,7 @@ except ImportError:
     import http.client as httplib
 
 import json
+import uuid
 
 from django.contrib.auth.models import User
 from django.db import models
@@ -27,6 +28,14 @@ class TestSortableModel(SortableMixin):
         return self.title
 
 
+class TestNonAutoFieldModel(SortableMixin):
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    order = models.PositiveIntegerField(editable=False, db_index=True)
+
+    class Meta:
+        ordering = ['order']
+
+
 class SortableTestCase(TestCase):
     def setUp(self):
         self.client = Client()
@@ -325,3 +334,7 @@ class SortableTestCase(TestCase):
         ]
         self.assertEqual(notes, expected_notes)
 
+    def test_save_non_auto_field_model(self):
+        model = TestNonAutoFieldModel()
+        model.save()
+