anchor.diff:              exec="<%= @command %>">
               <method_context working_directory="<%= @directory %>">
                 <method_credential user="<%= @user %>" />
  -              <% if @environment %>
  +              <% unless @environment.empty? %>
                   <method_environment>
                     <% @environment.each do |name,value| %>
                       <%= "<envvar name=\"#{name}\" value=\"#{value}\" />" %>
  
positive.code:             exec=":true">
              <method_context working_directory="<%= @directory %>">
                <method_credential user="<%= @user %>" />
                <% if @environment %>
                  <method_environment>
                    <% @environment.each do |name,value| %>
                      <%= "<envvar name=\"#{name}\" value=\"#{value}\" />" %>
  
negative.code:             exec=":kill">
              <method_context working_directory="<%= @directory %>">
                <method_credential user="<%= @user %>" />
                <% unless @environment.empty? %>
                  <method_environment>
                    <% @environment.each do |name,value| %>
                      <%= "<envvar name=\"#{name}\" value=\"#{value}\" />" %>
  