[chef] chef resources inherit not_if and only_if from previous copies

[Jeremy Deininger < >]

Greetings fellow chefs,

I believe I've found a bug in the way that resources are copied from one to the next during a recipe run.  This bug only manifests itself when you are re-using a resource with the same name.  My opinion is that only_if and not_if should be used to control the flow of actions that you use on the current_resource, not inherited from previous resources.  The primary example I use is the service "mysql" resource.  Since this service is likely to be called multiple times in a recipe with different actions it can be confusing when it inherits a conditional from a prior action ..  I've filed a bug here: http://tickets.opscode.com/browse/CHEF-894 and I'm pasting an example below that's taken from the Rightscale public cookbooks for db_mysql.

Do the maintainers approve this change?  Any alternatives or suggestions?  Right now I have to be really careful with my not/only_ifs and override the un-wanted copies to get the behavior I need..  

=== SNIP from http://github.com/rightscale/cookbooks_public/blob/master/cookbooks/db_mysql/recipes/install_mysql.rb#L125 ===>

service "mysql" do

  only_if do
    right_platform = node[:platform] == "ubuntu" && 
                    (node[:platform_version] == "8.04" || 
                     node[:platform_version] == "8.10")
 
    right_platform && node[:db_mysql][:kill_bug_mysqld_safe]
  end
 

  action :stop
end

 
ruby_block "fix buggy mysqld_safe" do

  only_if do
    right_platform = node[:platform] == "ubuntu" && 
                    (node[:platform_version] == "8.04" || 
                     node[:platform_version] == "8.10")
 
    right_platform && node[:db_mysql][:kill_bug_mysqld_safe]
  end
  block do

    ...
    node[:db_mysql][:kill_bug_mysqld_safe] = false
  end
end

service "mysql" do

  # override this back to the default for future copies of the resource
  only_if do true end
  not_if do ::File.symlink?(node[:db_mysql][:datadir]) end
  action :stop
end

... more recipe code ...

service "mysql" do
  # override this back to the default for future copies of the resource

  not_if do false end
  Chef::Log.info "Attempting to start mysql service"
  action :start
end