From 8c632a2bd8429a7a09b2125c5c2aae07730ded13 Mon Sep 17 00:00:00 2001
From: Atifa Perveen <atifa.perveen@elastica.co>
Date: Wed, 10 Oct 2018 16:09:01 +0500
Subject: [PATCH 1/2] Refs #81768: Added checks to prevent creating additional
 indexes on _id field. Sparse, unique and background options cannot be
 provided with index on primary key. Mongo 3.4 has strict validations on index
 creations and throws exceptions instead of just warnings.

---
 django_mongodb_engine/creation.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/django_mongodb_engine/creation.py b/django_mongodb_engine/creation.py
index bd0667f9..b22f6566 100644
--- a/django_mongodb_engine/creation.py
+++ b/django_mongodb_engine/creation.py
@@ -70,7 +70,8 @@ def _handle_newstyle_indexes(self, ensure_index, meta, indexes):
                 # field doesn't need an index.
                 continue
             column = '_id' if field.primary_key else field.column
-            ensure_index(column, unique=field.unique)
+            if not column == '_id':
+                ensure_index(column, unique=field.unique)
 
         # Django unique_together indexes.
         indexes = list(indexes)
@@ -122,9 +123,10 @@ def _handle_oldstyle_indexes(self, ensure_index, meta):
                 # field doesn't need an index.
                 continue
             column = '_id' if field.primary_key else field.column
-            if field.name in descending_indexes:
-                column = [(column, DESCENDING)]
-            ensure_index(column, unique=field.unique,
+            if not column == '_id':
+                if field.name in descending_indexes:
+                    column = [(column, DESCENDING)]
+                    ensure_index(column, unique=field.unique,
                          sparse=field.name in sparse_indexes)
 
         def create_compound_indexes(indexes, **kwargs):

From 0cf71e13ba2b9b92c04fd0e47d8ce24679d3d5c6 Mon Sep 17 00:00:00 2001
From: Arsalan Khairani <arsalan.khairani@elastica.co>
Date: Fri, 2 Nov 2018 13:25:32 +0500
Subject: [PATCH 2/2] Indentation Fix

---
 django_mongodb_engine/creation.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/django_mongodb_engine/creation.py b/django_mongodb_engine/creation.py
index b22f6566..fb47f0b3 100644
--- a/django_mongodb_engine/creation.py
+++ b/django_mongodb_engine/creation.py
@@ -126,8 +126,7 @@ def _handle_oldstyle_indexes(self, ensure_index, meta):
             if not column == '_id':
                 if field.name in descending_indexes:
                     column = [(column, DESCENDING)]
-                    ensure_index(column, unique=field.unique,
-                         sparse=field.name in sparse_indexes)
+                ensure_index(column, unique=field.unique, sparse=field.name in sparse_indexes)
 
         def create_compound_indexes(indexes, **kwargs):
             # indexes: (field1, field2, ...).