From d980d170a6a58df573c0b78211fd35a9d33286a2 Mon Sep 17 00:00:00 2001
From: Collins Abitekaniza <abtcolns@gmail.com>
Date: Sat, 8 Dec 2018 13:48:05 +0300
Subject: [PATCH 1/2] error on duplicate mount points

Signed-off-by: Collins Abitekaniza <abtcolns@gmail.com>
---
 compose/config/config.py | 12 ++++++++++++
 compose/service.py       |  1 +
 2 files changed, 13 insertions(+)

diff --git a/compose/config/config.py b/compose/config/config.py
index 0298b4e2d..59c76680b 100644
--- a/compose/config/config.py
+++ b/compose/config/config.py
@@ -8,6 +8,7 @@ import os
 import string
 import sys
 from collections import namedtuple
+from operator import itemgetter, attrgetter
 
 import six
 import yaml
@@ -835,6 +836,17 @@ def finalize_service_volumes(service_dict, environment):
                 finalized_volumes.append(MountSpec.parse(v, normalize, win_host))
             else:
                 finalized_volumes.append(VolumeSpec.parse(v, normalize, win_host))
+
+        duplicate_mounts = []
+        mounts = [v.as_volume_spec() if isinstance(v, MountSpec) else v for v in finalized_volumes]
+        for mount in mounts:
+            if list(map(attrgetter('internal'), mounts)).count(mount.internal) > 1:
+                duplicate_mounts.append(mount.repr())
+
+        if duplicate_mounts:
+            raise ConfigurationError("Duplicate mount points: volumes [%s]" % (
+                ', '.join(duplicate_mounts)))
+        
         service_dict['volumes'] = finalized_volumes
 
     return service_dict
diff --git a/compose/service.py b/compose/service.py
index f6dfa7c72..964ab0193 100644
--- a/compose/service.py
+++ b/compose/service.py
@@ -9,6 +9,7 @@ import sys
 from collections import namedtuple
 from collections import OrderedDict
 from operator import attrgetter
+from operator import itemgetter
 
 import enum
 import six

From 47ff8d710c62a2c58e359ac41a90d7b6c411de90 Mon Sep 17 00:00:00 2001
From: Collins Abitekaniza <abtcolns@gmail.com>
Date: Sun, 9 Dec 2018 00:43:06 +0300
Subject: [PATCH 2/2] test create from config with duplicate mount points

Signed-off-by: Collins Abitekaniza <abtcolns@gmail.com>
---
 compose/config/config.py         |  6 +++---
 compose/service.py               |  1 -
 tests/unit/config/config_test.py | 35 ++++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/compose/config/config.py b/compose/config/config.py
index 59c76680b..d9ee158d5 100644
--- a/compose/config/config.py
+++ b/compose/config/config.py
@@ -8,7 +8,7 @@ import os
 import string
 import sys
 from collections import namedtuple
-from operator import itemgetter, attrgetter
+from operator import attrgetter
 
 import six
 import yaml
@@ -844,9 +844,9 @@ def finalize_service_volumes(service_dict, environment):
                 duplicate_mounts.append(mount.repr())
 
         if duplicate_mounts:
-            raise ConfigurationError("Duplicate mount points: volumes [%s]" % (
+            raise ConfigurationError("Duplicate mount points: [%s]" % (
                 ', '.join(duplicate_mounts)))
-        
+
         service_dict['volumes'] = finalized_volumes
 
     return service_dict
diff --git a/compose/service.py b/compose/service.py
index 964ab0193..f6dfa7c72 100644
--- a/compose/service.py
+++ b/compose/service.py
@@ -9,7 +9,6 @@ import sys
 from collections import namedtuple
 from collections import OrderedDict
 from operator import attrgetter
-from operator import itemgetter
 
 import enum
 import six
diff --git a/tests/unit/config/config_test.py b/tests/unit/config/config_test.py
index 787d8ff4a..f95c46d89 100644
--- a/tests/unit/config/config_test.py
+++ b/tests/unit/config/config_test.py
@@ -3071,6 +3071,41 @@ class ConfigTest(unittest.TestCase):
         )
         config.load(config_details)
 
+    def test_config_duplicate_mount_points(self):
+        config1 = build_config_details(
+            {
+                'version': '3.5',
+                'services': {
+                    'web': {
+                        'image': 'busybox',
+                        'volumes': ['/tmp/foo:/tmp/foo', '/tmp/foo:/tmp/foo:rw']
+                    }
+                }
+            }
+        )
+
+        config2 = build_config_details(
+            {
+                'version': '3.5',
+                'services': {
+                    'web': {
+                        'image': 'busybox',
+                        'volumes': ['/x:/y', '/z:/y']
+                    }
+                }
+            }
+        )
+
+        with self.assertRaises(ConfigurationError) as e:
+            config.load(config1)
+        self.assertEquals(str(e.exception), 'Duplicate mount points: [%s]' % (
+            ', '.join(['/tmp/foo:/tmp/foo:rw']*2)))
+
+        with self.assertRaises(ConfigurationError) as e:
+            config.load(config2)
+        self.assertEquals(str(e.exception), 'Duplicate mount points: [%s]' % (
+            ', '.join(['/x:/y:rw', '/z:/y:rw'])))
+
 
 class NetworkModeTest(unittest.TestCase):