From 22d91f60bea78cbe232a1ac86ba747930ecf7d1a Mon Sep 17 00:00:00 2001
From: realityone <realityone@me.com>
Date: Fri, 14 Oct 2016 18:20:55 +0800
Subject: [PATCH] fix serialize restart spec with null string

Signed-off-by: realityone <realityone@me.com>
---
 compose/config/types.py                   | 2 ++
 tests/acceptance/cli_test.py              | 4 ++++
 tests/fixtures/restart/docker-compose.yml | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/compose/config/types.py b/compose/config/types.py
index 9664b580..c450a0f9 100644
--- a/compose/config/types.py
+++ b/compose/config/types.py
@@ -93,6 +93,8 @@ def parse_restart_spec(restart_config):
 
 
 def serialize_restart_spec(restart_spec):
+    if not restart_spec:
+        return ''
     parts = [restart_spec['Name']]
     if restart_spec['MaximumRetryCount']:
         parts.append(six.text_type(restart_spec['MaximumRetryCount']))
diff --git a/tests/acceptance/cli_test.py b/tests/acceptance/cli_test.py
index 0c7c17bd..e2c02798 100644
--- a/tests/acceptance/cli_test.py
+++ b/tests/acceptance/cli_test.py
@@ -236,6 +236,10 @@ class CLITestCase(DockerClientTestCase):
                     'image': 'busybox',
                     'restart': 'on-failure:5',
                 },
+                'restart-null': {
+                    'image': 'busybox',
+                    'restart': ''
+                },
             },
             'networks': {},
             'volumes': {},
diff --git a/tests/fixtures/restart/docker-compose.yml b/tests/fixtures/restart/docker-compose.yml
index 2d10aa39..ecfdfbf5 100644
--- a/tests/fixtures/restart/docker-compose.yml
+++ b/tests/fixtures/restart/docker-compose.yml
@@ -12,3 +12,6 @@ services:
   on-failure-5:
     image: busybox
     restart: "on-failure:5"
+  restart-null:
+    image: busybox
+    restart: ""