From 7cb46d0761e6b058d55f8ad93f584fa6bb6ade15 Mon Sep 17 00:00:00 2001
From: Ross Lawley <ross.lawley@gmail.com>
Date: Wed, 10 Jul 2013 09:11:50 +0000
Subject: [PATCH] Fixed ListField setslice and delslice dirty tracking (#390)

---
 AUTHORS                            |  3 ++-
 docs/changelog.rst                 |  1 +
 mongoengine/base/datastructures.py |  8 ++++++++
 tests/fields/fields.py             | 26 ++++++++++++++++++++++++++
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index a50eb570..e88de8c6 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -170,4 +170,5 @@ that much better:
  * Nigel McNie (https://github.com/nigelmcnie)
  * ygbourhis (https://github.com/ygbourhis)
  * Bob Dickinson (https://github.com/BobDickinson)
- * Michael Bartnett (https://github.com/michaelbartnett)
\ No newline at end of file
+ * Michael Bartnett (https://github.com/michaelbartnett)
+ * Alon Horev (https://github.com/alonho)
\ No newline at end of file
diff --git a/docs/changelog.rst b/docs/changelog.rst
index f433f21e..27d51a43 100644
--- a/docs/changelog.rst
+++ b/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)
diff --git a/mongoengine/base/datastructures.py b/mongoengine/base/datastructures.py
index adcd8d04..4652fb56 100644
--- a/mongoengine/base/datastructures.py
+++ b/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
diff --git a/tests/fields/fields.py b/tests/fields/fields.py
index 3e48a214..8f024991 100644
--- a/tests/fields/fields.py
+++ b/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."""