Fixing django-cms#1649 - NoReverseMatch raised if apphook doesn't exist

Some apps, like cmsplugin-zinnia and cmsplugin_news will raise NoReverseMatch when trying to generate their menus before an apphook is installed. In sampleapp this is solved by adding a try-except like the one in this commit. Placing the try-except in django-cms instead of inside every app would simplify the process of writing plugins and avoid some confusing 500-errors for new users trying to install plugins.

menus/menu_pool.py

@@ -3,6 +3,7 @@
 from django.conf import settings
 from django.contrib.sites.models import Site
 from django.core.cache import cache
+from django.core.urlresolvers import NoReverseMatch
 from django.utils.translation import get_language
 from menus.exceptions import NamespaceAllreadyRegistered
 from menus.models import CacheKey
@@ -131,7 +132,12 @@ def _build_nodes(self, request, site_id):
 
         final_nodes = []
         for menu_class_name in self.menus:
-            nodes = self.menus[menu_class_name].get_nodes(request)
+            try:
+                nodes = self.menus[menu_class_name].get_nodes(request)
+            except NoReverseMatch:
+                # Apps might raise NoReverseMatch if an apphook does not yet
+                # exist, skip them instead of crashing
+                pass
             # nodes is a list of navigation nodes (page tree in cms + others)
             final_nodes += _build_nodes_inner_for_one_menu(nodes, menu_class_name)
         cache.set(key, final_nodes, settings.CMS_CACHE_DURATIONS['menus'])