Used lazy choices for display list names

Signed-off-by: Alexandre Barbosa <alexandreab@live.com>
Signed-off-by: Lucas Moura <lucas.moura128@gmail.com>
Signed-off-by: Macartur Sousa <macartur.sc@gmail.com>
Signed-off-by: Sergio Oliveira <sergio@tracy.com.br>

colab/accounts/forms.py

@@ -11,6 +11,7 @@
 from django.core.urlresolvers import reverse
 from django.template import loader
 from django.utils.encoding import force_bytes
+from django.utils.functional import lazy
 from django.utils.http import urlsafe_base64_encode
 from django.utils.text import capfirst
 from django.utils.translation import ugettext_lazy as _
@@ -139,16 +140,32 @@ class Meta:
                                       required=False)
 
 
+def get_lists_choices():
+    lists_names = []
+    for mlist in mailman.all_lists():
+        name = mlist.get('listname')
+        desc = mlist.get('description')
+        formatted_desc = u'{} ({})'.format(name, desc)
+        lists_names.append((name, formatted_desc))
+    return lists_names
+
+
+# XXX: This field is no longer required when using django 1.8
+class MultipleChoiceFieldLazy(forms.MultipleChoiceField):
+    def _set_choices(self, value):
+        self._choices = self.widget.choices = value
+
+    def _get_choices(self):
+        return list(self._choices)
+
+    choices = property(_get_choices, _set_choices)
+
+
 class ListsForm(forms.Form):
-    LISTS_NAMES = ((
-        mlist.get('listname'), u'{} ({})'.format(mlist.get('listname'),
-                                                 mlist.get('description'))
-    ) for mlist in mailman.all_lists())
-
-    lists = forms.MultipleChoiceField(label=_(u'Mailing lists'),
-                                      required=False,
-                                      widget=forms.CheckboxSelectMultiple,
-                                      choices=LISTS_NAMES)
+    lists = MultipleChoiceFieldLazy(label=_(u'Mailing lists'),
+                                    required=False,
+                                    widget=forms.CheckboxSelectMultiple,
+                                    choices=lazy(get_lists_choices, list)())
 
 
 class UserCreationForm(UserForm):