From 421981e7d26bd5a5558d1bfdc8079749b15bb7bf Mon Sep 17 00:00:00 2001
From: Daniel Nephin <dnephin@docker.com>
Date: Mon, 8 Feb 2016 12:18:48 -0500
Subject: [PATCH] Use 12 characters for the short id to match docker and fix
 backwards compatibility.

Signed-off-by: Daniel Nephin <dnephin@docker.com>
---
 compose/container.py         |  2 +-
 tests/unit/container_test.py | 22 +++++++++++++++-------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/compose/container.py b/compose/container.py
index 2565c8ffc..3a1ce0b9f 100644
--- a/compose/container.py
+++ b/compose/container.py
@@ -60,7 +60,7 @@ class Container(object):
 
     @property
     def short_id(self):
-        return self.id[:10]
+        return self.id[:12]
 
     @property
     def name(self):
diff --git a/tests/unit/container_test.py b/tests/unit/container_test.py
index 886911504..189b0c992 100644
--- a/tests/unit/container_test.py
+++ b/tests/unit/container_test.py
@@ -12,8 +12,9 @@ from compose.container import get_container_name
 class ContainerTest(unittest.TestCase):
 
     def setUp(self):
+        self.container_id = "abcabcabcbabc12345"
         self.container_dict = {
-            "Id": "abc",
+            "Id": self.container_id,
             "Image": "busybox:latest",
             "Command": "top",
             "Created": 1387384730,
@@ -41,19 +42,22 @@ class ContainerTest(unittest.TestCase):
         self.assertEqual(
             container.dictionary,
             {
-                "Id": "abc",
+                "Id": self.container_id,
                 "Image": "busybox:latest",
                 "Name": "/composetest_db_1",
             })
 
     def test_from_ps_prefixed(self):
-        self.container_dict['Names'] = ['/swarm-host-1' + n for n in self.container_dict['Names']]
+        self.container_dict['Names'] = [
+            '/swarm-host-1' + n for n in self.container_dict['Names']
+        ]
 
-        container = Container.from_ps(None,
-                                      self.container_dict,
-                                      has_been_inspected=True)
+        container = Container.from_ps(
+            None,
+            self.container_dict,
+            has_been_inspected=True)
         self.assertEqual(container.dictionary, {
-            "Id": "abc",
+            "Id": self.container_id,
             "Image": "busybox:latest",
             "Name": "/composetest_db_1",
         })
@@ -142,6 +146,10 @@ class ContainerTest(unittest.TestCase):
         self.assertEqual(container.get('HostConfig.VolumesFrom'), ["volume_id"])
         self.assertEqual(container.get('Foo.Bar.DoesNotExist'), None)
 
+    def test_short_id(self):
+        container = Container(None, self.container_dict, has_been_inspected=True)
+        assert container.short_id == self.container_id[:12]
+
 
 class GetContainerNameTestCase(unittest.TestCase):