From 516907540b81c009b74d29b2fa36319b47528b49 Mon Sep 17 00:00:00 2001
From: Marten Kenbeek <marten.knbk@gmail.com>
Date: Sun, 19 Apr 2015 23:40:24 +0200
Subject: [PATCH] [1.8.x] Refs #24591 -- Optimized cloning of ModelState
 objects.

Changed ModelState.clone() to create a deepcopy of self.fields.
---
 django/db/migrations/state.py |  2 +-
 docs/releases/1.8.1.txt       | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/django/db/migrations/state.py b/django/db/migrations/state.py
index 9cf63a2cee..5754bd3a97 100644
--- a/django/db/migrations/state.py
+++ b/django/db/migrations/state.py
@@ -496,7 +496,7 @@ class ModelState(object):
         return self.__class__(
             app_label=self.app_label,
             name=self.name,
-            fields=list(self.construct_fields()),
+            fields=[(name, copy.deepcopy(field)) for name, field in self.fields],
             options=dict(self.options),
             bases=self.bases,
             managers=list(self.construct_managers()),
diff --git a/docs/releases/1.8.1.txt b/docs/releases/1.8.1.txt
index 7f9608d8b7..b226b0928c 100644
--- a/docs/releases/1.8.1.txt
+++ b/docs/releases/1.8.1.txt
@@ -4,7 +4,8 @@ Django 1.8.1 release notes
 
 *Under development*
 
-Django 1.8.1 fixes several bugs in 1.8.
+Django 1.8.1 fixes several bugs in 1.8 and includes some optimizations in the
+migrations framework.
 
 Bugfixes
 ========
@@ -61,3 +62,11 @@ Bugfixes
 
 * Fixed JavaScript path of ``contrib.admin``’s related field widget when using
   alternate static file storages (:ticket:`24655`).
+
+Optimizations
+=============
+
+* Changed ``ModelState`` to deepcopy fields instead of deconstructing and
+  reconstructing (:ticket:`24591`). This speeds up the rendering of model
+  states and reduces memory usage when running :djadmin:`manage.py migrate
+  <migrate>`.