Fixed ListField setslice and delslice dirty tracking (#390)

AUTHORS

@@ -171,3 +171,4 @@ that much better:
  * ygbourhis (https://github.com/ygbourhis)
  * Bob Dickinson (https://github.com/BobDickinson)
  * Michael Bartnett (https://github.com/michaelbartnett)
+ * Alon Horev (https://github.com/alonho)

docs/changelog.rst

@@ -4,6 +4,7 @@ Changelog
 
 Changes in 0.8.3
 ================
+- Fixed ListField setslice and delslice dirty tracking (#390)
 - Added Django 1.5 PY3 support (#392)
 - Added match ($elemMatch) support for EmbeddedDocuments (#379)
 - Fixed weakref being valid after reload (#374)

mongoengine/base/datastructures.py

@@ -108,6 +108,14 @@ class BaseList(list):
         self._mark_as_changed()
         return super(BaseList, self).__delitem__(*args, **kwargs)
 
+    def __setslice__(self, *args, **kwargs):
+        self._mark_as_changed()
+        return super(BaseList, self).__setslice__(*args, **kwargs)
+
+    def __delslice__(self, *args, **kwargs):
+        self._mark_as_changed()
+        return super(BaseList, self).__delslice__(*args, **kwargs)
+
     def __getstate__(self):
         self.instance = None
         self._dereferenced = False

tests/fields/fields.py

@@ -1018,6 +1018,32 @@ class FieldTest(unittest.TestCase):
         e.mapping = {}
         self.assertEqual([], e._changed_fields)
 
+    def test_slice_marks_field_as_changed(self):
+
+        class Simple(Document):
+            widgets = ListField()
+
+        simple = Simple(widgets=[1, 2, 3, 4]).save()
+        simple.widgets[:3] = []
+        self.assertEqual(['widgets'], simple._changed_fields)
+        simple.save()
+
+        simple = simple.reload()
+        self.assertEqual(simple.widgets, [4])
+
+    def test_del_slice_marks_field_as_changed(self):
+
+        class Simple(Document):
+            widgets = ListField()
+
+        simple = Simple(widgets=[1, 2, 3, 4]).save()
+        del simple.widgets[:3]
+        self.assertEqual(['widgets'], simple._changed_fields)
+        simple.save()
+
+        simple = simple.reload()
+        self.assertEqual(simple.widgets, [4])
+
     def test_list_field_complex(self):
         """Ensure that the list fields can handle the complex types."""