Improved fix for #18373 -- backward compatibility

Commit 79558c78 cleaned up the (undocumented) interface of Resolver404
exception, which breaks compatibility with code messing with .args[0]
directly. Revert the cleanup part and simply leave the fix itself.

django/core/urlresolvers.py

@@ -69,11 +69,8 @@ class ResolverMatch(object):
 
 
 class Resolver404(Http404):
+    pass
 
-    def __init__(self, path, tried=None):
-        super(Resolver404, self).__init__()
-        self.path = path
-        self.tried = tried
 
 
 class NoReverseMatch(Exception):
@@ -326,7 +323,7 @@ class RegexURLResolver(LocaleRegexProvider):
                 try:
                     sub_match = pattern.resolve(new_path)
                 except Resolver404 as e:
-                    sub_tried = e.tried
+                    sub_tried = e.args[0].get('tried')
                     if sub_tried is not None:
                         tried.extend([pattern] + t for t in sub_tried)
                     else:
@@ -337,8 +334,8 @@ class RegexURLResolver(LocaleRegexProvider):
                         sub_match_dict.update(sub_match.kwargs)
                         return ResolverMatch(sub_match.func, sub_match.args, sub_match_dict, sub_match.url_name, self.app_name or sub_match.app_name, [self.namespace] + sub_match.namespaces)
                     tried.append([pattern])
-            raise Resolver404(new_path, tried=tried)
-        raise Resolver404(path)
+            raise Resolver404({'tried': tried, 'path': new_path})
+        raise Resolver404({'path': path})
 
     @property
     def urlconf_module(self):

django/views/debug.py

@@ -475,11 +475,14 @@ class ExceptionReporter(object):
 def technical_404_response(request, exception):
     "Create a technical 404 error response. The exception should be the Http404."
     try:
-        tried = exception.tried
-        error_url = exception.path
-    except AttributeError:
+        error_url = exception.args[0]['path']
+    except (IndexError, TypeError, KeyError):
+        error_url = request.path_info[1:] # Trim leading slash
+
+    try:
+        tried = exception.args[0]['tried']
+    except (IndexError, TypeError, KeyError):
         tried = []
-        error_url = request.path_info[1:]  # Trim leading slash
     else:
         if (not tried                           # empty URLconf
             or (request.path == '/'