From 175659628d2150556ee33e19dec088816802ddbe Mon Sep 17 00:00:00 2001
From: Catstyle <Catstyle.Lee@gmail.com>
Date: Fri, 10 Apr 2015 11:31:31 +0800
Subject: [PATCH] fix mark_as_changed: handle higher/lower level changed fields
 correctly to avoid conflict update error

---
 AUTHORS                      |  1 +
 docs/changelog.rst           |  1 +
 mongoengine/base/document.py | 14 +++++++++-
 tests/document/delta.py      | 50 ++++++++++++++++++++++++++++++++++++
 4 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 0fd40b51..af87d503 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -220,3 +220,4 @@ that much better:
  * J. Fernando Sánchez (https://github.com/balkian)
  * Michael Chase (https://github.com/rxsegrxup)
  * Eremeev Danil (https://github.com/elephanter)
+ * Catstyle Lee (https://github.com/Catstyle)
diff --git a/docs/changelog.rst b/docs/changelog.rst
index ba952d8e..188247e6 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -5,6 +5,7 @@ Changelog
 
 Changes in 0.9.X - DEV
 ======================
+- Fixed mark_as_changed to handle higher/lower level fields changed. #927
 - ListField of embedded docs doesn't set the _instance attribute when iterating over it #914
 - Support += and *= for ListField #595
 - Use sets for populating dbrefs to dereference
diff --git a/mongoengine/base/document.py b/mongoengine/base/document.py
index b2310439..33a6d826 100644
--- a/mongoengine/base/document.py
+++ b/mongoengine/base/document.py
@@ -483,7 +483,19 @@ class BaseDocument(object):
             key = self._db_field_map.get(key, key)
 
         if key not in self._changed_fields:
-            self._changed_fields.append(key)
+            levels, idx = key.split('.'), 1
+            while idx <= len(levels):
+                if '.'.join(levels[:idx]) in self._changed_fields:
+                    break
+                idx += 1
+            else:
+                self._changed_fields.append(key)
+                # remove lower level changed fields
+                level = '.'.join(levels[:idx]) + '.'
+                remove = self._changed_fields.remove
+                for field in self._changed_fields:
+                    if field.startswith(level):
+                        remove(field)
 
     def _clear_changed_fields(self):
         """Using get_changed_fields iterate and remove any fields that are
diff --git a/tests/document/delta.py b/tests/document/delta.py
index 58df2c82..7ec6ee56 100644
--- a/tests/document/delta.py
+++ b/tests/document/delta.py
@@ -735,6 +735,56 @@ class DeltaTest(unittest.TestCase):
         mydoc._clear_changed_fields()
         self.assertEqual([], mydoc._get_changed_fields())
 
+    def test_lower_level_mark_as_changed(self):
+        class EmbeddedDoc(EmbeddedDocument):
+            name = StringField()
+
+        class MyDoc(Document):
+            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
+
+        MyDoc.drop_collection()
+
+        MyDoc().save()
+
+        mydoc = MyDoc.objects.first()
+        mydoc.subs['a'] = EmbeddedDoc()
+        self.assertEqual(["subs.a"], mydoc._get_changed_fields())
+
+        subdoc = mydoc.subs['a']
+        subdoc.name = 'bar'
+
+        self.assertEqual(["name"], subdoc._get_changed_fields())
+        self.assertEqual(["subs.a"], mydoc._get_changed_fields())
+        mydoc.save()
+
+        mydoc._clear_changed_fields()
+        self.assertEqual([], mydoc._get_changed_fields())
+
+    def test_upper_level_mark_as_changed(self):
+        class EmbeddedDoc(EmbeddedDocument):
+            name = StringField()
+
+        class MyDoc(Document):
+            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
+
+        MyDoc.drop_collection()
+
+        MyDoc(subs={'a': EmbeddedDoc(name='foo')}).save()
+
+        mydoc = MyDoc.objects.first()
+        subdoc = mydoc.subs['a']
+        subdoc.name = 'bar'
+
+        self.assertEqual(["name"], subdoc._get_changed_fields())
+        self.assertEqual(["subs.a.name"], mydoc._get_changed_fields())
+
+        mydoc.subs['a'] = EmbeddedDoc()
+        self.assertEqual(["subs.a"], mydoc._get_changed_fields())
+        mydoc.save()
+
+        mydoc._clear_changed_fields()
+        self.assertEqual([], mydoc._get_changed_fields())
+
     def test_referenced_object_changed_attributes(self):
         """Ensures that when you save a new reference to a field, the referenced object isn't altered"""