## New NonRecurringFileSystem

# Prevents horrible bug with include tag that can take out your server.
#

module Liquid
  class NonRecurringFileSystem
    attr_accessor :include_stack
    def initialize()
      # Stores a stack of included templates
      # so that we don't double-include and cause an infinite loop.
      @include_stack = []
    end

    def read_template_file(template_name)
      @include_stack << template_name
      # ... Do stuff to get file here and return content
      return content
    end
  end
end

## Patch for include.rb that doesn't allow infinite loops

Index: vendor/plugins/liquid/lib/liquid/tags/include.rb
===================================================================
--- vendor/plugins/liquid/lib/liquid/tags/include.rb	(revision 697)
+++ vendor/plugins/liquid/lib/liquid/tags/include.rb	(working copy)
@@ -24,7 +24,10 @@
     end

     def render(context)
-      source  = Liquid::Template.file_system.read_template_file(context[@template_name])
+      # Make sure not to get into infinite loops of inclusion.
+      return if Liquid::Template.file_system.include_stack.include?(context[@template_name])
+
+      source  = Liquid::Template.file_system.read_template_file(context[@template_name])
       partial = Liquid::Template.parse(source)

       variable = context[@variable_name || @template_name[1..-2]]
@@ -48,6 +51,9 @@

         end
       end
+
+    ensure
+      Liquid::Template.file_system.include_stack.pop
     end
   end