[wip] Handle macros outside Rails' view_context

This presents a more graceful notice, rather than rendering an error.

Signed-off-by: Alex Coles <alex@alexbcoles.com>

lib/open_project/wiki_formatting/macros/timelines_wiki_macro.rb

@@ -40,8 +40,12 @@ module OpenProject
 
           view = options[:view]
 
-          view.render :partial => '/timelines/timeline',
-                      :locals => {:timeline => timeline}
+          if view.respond_to?(:render)
+            view.render :partial => '/timelines/timeline',
+                        :locals => {:timeline => timeline}
+          else
+            raise NotImplementedError, 'Timeline rendering is not supported'
+          end
         end
       end
     end

lib/redmine/wiki_formatting.rb

@@ -104,6 +104,8 @@ module Redmine
               macros_runner.call(macro, args)
             rescue => e
               "<div class=\"flash error\">Error executing the <strong>#{macro}</strong> macro (#{e})</div>"
+            rescue NotImplementedError
+              "<div class=\"macro-unavailable\">Macro <strong>#{macro}</strong> cannot be displayed.</div>"
             end || all
           else
             all