From d5ea68dd2e815681b32721afe3c2855a1c17f9aa Mon Sep 17 00:00:00 2001
From: Federico Capoano <nemesis@ninux.org>
Date: Tue, 3 Nov 2015 14:51:18 +0100
Subject: [PATCH] Allowed empty bridges #22

---
 netjsonconfig/backends/openwrt/renderers.py | 10 +++++++--
 netjsonconfig/schema.py                     |  9 +++-----
 tests/openwrt/test_network.py               | 23 +++++++++++++++++++++
 3 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/netjsonconfig/backends/openwrt/renderers.py b/netjsonconfig/backends/openwrt/renderers.py
index 02180f539..4f11059d2 100644
--- a/netjsonconfig/backends/openwrt/renderers.py
+++ b/netjsonconfig/backends/openwrt/renderers.py
@@ -79,8 +79,14 @@ def _get_interfaces(self):
                 })
                 # bridging
                 if is_bridge:
-                    uci_interface['ifname'] = bridge_members
                     uci_interface['type'] = 'bridge'
+                    # put bridge members in ifname attribute
+                    if bridge_members:
+                        uci_interface['ifname'] = bridge_members
+                    # if no members, this is an empty bridge
+                    else:
+                        uci_interface['bridge_empty'] = True
+                        del uci_interface['ifname']
                     # ensure type "bridge" is only given to one logical interface
                     is_bridge = False
                 # bridge has already been defined
@@ -91,7 +97,7 @@ def _get_interfaces(self):
                     # to these physical names
                     uci_interface['ifname'] = 'br-{0}'.format(interface['name'])
                 # delete bridge_members attribtue
-                if uci_interface.get('bridge_members'):
+                if uci_interface.get('bridge_members') is not None:
                     del uci_interface['bridge_members']
                 # add address if any (with correct option name)
                 if address_key and address_value:
diff --git a/netjsonconfig/schema.py b/netjsonconfig/schema.py
index 39be57119..2d9373c57 100644
--- a/netjsonconfig/schema.py
+++ b/netjsonconfig/schema.py
@@ -224,12 +224,9 @@
                         "bridge_members": {
                             "type": "array",
                             "title": "Bridge Members",
-                            "minItems": 1,
-                            "items": [
-                                {
-                                    "type": "string"
-                                }
-                            ]
+                            "items": {
+                                "type": "string"
+                            }
                         }
                     }
                 }
diff --git a/tests/openwrt/test_network.py b/tests/openwrt/test_network.py
index 44c06eb15..9ef2151e9 100644
--- a/tests/openwrt/test_network.py
+++ b/tests/openwrt/test_network.py
@@ -418,6 +418,26 @@ def test_eth_bridge(self):
 """)
         self.assertEqual(o.render(), expected)
 
+    def test_empty_bridge(self):
+        o = OpenWrt({
+            "interfaces": [
+                {
+                    "network": "lan",
+                    "name": "br-lan",
+                    "type": "bridge",
+                    "bridge_members": []
+                }
+            ]
+        })
+        expected = self._tabs("""package network
+
+config interface 'lan'
+    option bridge_empty '1'
+    option proto 'none'
+    option type 'bridge'
+""")
+        self.assertEqual(o.render(), expected)
+
     def test_dns(self):
         o = OpenWrt({
             "interfaces": [
@@ -604,6 +624,9 @@ def test_bridge_members_schema(self):
                 }
             ]
         })
+        with self.assertRaises(ValidationError):
+            o.validate()
+        o.config['interfaces'][0]['bridge_members'] = [3]
         with self.assertRaises(ValidationError):
             o.validate()
         # ensure fix works