Fix bug #1965 of $position and $push operators do not work with list in an EmbeddedDocument. Set key value to joined parts excluding the index at the end. Added test case

Author: tjhall13

AUTHORS

@@ -247,3 +247,4 @@ that much better:
  * Erdenezul Batmunkh (https://github.com/erdenezul)
  * Andy Yankovsky (https://github.com/werat)
  * Bastien Gérard (https://github.com/bagerard)
+ * Trevor Hall (https://github.com/tjhall13)

mongoengine/queryset/transform.py

@@ -345,7 +345,7 @@ def update(_doc_cls=None, **update):
             value = {key: {'$each': value}}
         elif op in ('push', 'pushAll'):
             if parts[-1].isdigit():
-                key = parts[0]
+                key = '.'.join(parts[0:-1])
                 position = int(parts[-1])
                 # $position expects an iterable. If pushing a single value,
                 # wrap it in a list.

tests/document/instance.py

@@ -842,10 +842,16 @@ def test_modify_update(self):
 
     @requires_mongodb_gte_26
     def test_modify_with_positional_push(self):
+        class Content(EmbeddedDocument):
+            keywords = ListField(StringField())
+
         class BlogPost(Document):
             tags = ListField(StringField())
+            content = EmbeddedDocumentField(Content)
+
+        post = BlogPost.objects.create(
+            tags=['python'], content=Content(keywords=['ipsum']))
 
-        post = BlogPost.objects.create(tags=['python'])
         self.assertEqual(post.tags, ['python'])
         post.modify(push__tags__0=['code', 'mongo'])
         self.assertEqual(post.tags, ['code', 'mongo', 'python'])
@@ -856,6 +862,16 @@ class BlogPost(Document):
             ['code', 'mongo', 'python']
         )
 
+        self.assertEqual(post.content.keywords, ['ipsum'])
+        post.modify(push__content__keywords__0=['lorem'])
+        self.assertEqual(post.content.keywords, ['lorem', 'ipsum'])
+
+        # Assert same order of the list items is maintained in the db
+        self.assertEqual(
+            BlogPost._get_collection().find_one({'_id': post.pk})['content']['keywords'],
+            ['lorem', 'ipsum']
+        )
+
     def test_save(self):
         """Ensure that a document may be saved in the database."""