Fix django-netfields usage and version

- there was a typo on the upper-bound in requirements.txt
- Upgrade to 0.4.x has less bugs than 0.3.x (and do not change data structure)
- it seems that django-netfields can no longer work without being added to INSTALLED_APPS
- workaround a bug with that Django/netfields versions combination preventing
  from using Q expressions.

See also ddf8ebe
Ref https://code.ffdn.org/FFDN/coin/pulls/99#issuecomment-401

coin/resources/models.py

@@ -4,7 +4,6 @@ from __future__ import unicode_literals
 from django.db import models
 from django.core.exceptions import ValidationError
 from django.core.validators import MaxValueValidator
-from django.db.models import Q
 from netfields import CidrAddressField, NetManager
 from netaddr import IPSet
 
@@ -85,9 +84,18 @@ class IPSubnet(models.Model):
         if not self.inet in self.ip_pool.inet:
             raise ValidationError("Le sous-réseau doit être inclus dans le bloc d'IP.")
         # Check that we don't conflict with existing subnets.
-        conflicting = self.ip_pool.ipsubnet_set.filter(Q(inet__net_contained_or_equal=self.inet) |
-                                                       Q(inet__net_contains_or_equals=self.inet)).exclude(id=self.id)
-        if conflicting:
+
+        # The optimal request would be the following commented request, but
+        # django-netfields 0.4.x seems buggy with Q-expressions. For now use
+        # two requests, but the optimal solution will have to be retried once
+        # we use django-netfields>=0.7
+
+        #conflicting = self.ip_pool.ipsubnet_set.filter(Q(inet__net_contained_or_equal=self.inet) |
+        #                                               Q(inet__net_contains_or_equals=self.inet)).exclude(id=self.id)
+        conflicting_contained = self.ip_pool.ipsubnet_set.filter(inet__net_contained_or_equal=self.inet).exclude(id=self.id)
+        conflicting_containing = self.ip_pool.ipsubnet_set.filter(inet__net_contains_or_equals=self.inet).exclude(id=self.id)
+        if conflicting_contained or conflicting_containing:
+            conflicting = conflicting_contained if conflicting_contained else conflicting_containing
             raise ValidationError("Le sous-réseau est en conflit avec des sous-réseaux existants: {}.".format(conflicting))
 
     def validate_reverse_dns(self):

coin/settings_base.py

@@ -149,6 +149,7 @@ INSTALLED_APPS = (
     'django.contrib.staticfiles',
     # Uncomment the next line to enable the admin:
     'django.contrib.admin',
+    'netfields',
     # Uncomment the next line to enable admin documentation:
     #'django.contrib.admindocs',
     'polymorphic',

requirements.txt

@@ -9,7 +9,7 @@ html2text
 django-polymorphic==0.7.2
 django-sendfile==0.3.10
 django-localflavor==1.1
-django-netfields>=0.3.1,<4.0
+django-netfields>=0.4,<0.5
 django-ldapdb>=0.4.0,<5.0
 feedparser
 six==1.10.0