Getting error with ancestry gem

Question

I am trying to add ancestry to an Event_Tags model that I have. Right now that model only has a name. I added 'ancestry' to the gemfile and bundled. Now when I go to run the following command:

rails g migration AddAncestryToEventTags ancestry:string

I get the following error:

/Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/ancestry- 2.0.0/lib/ancestry/has_ancestry.rb:7:in `block in has_ancestry': Unknown option for has_ancestry: :hierarchy_class_name => "TagHierarchy". (Ancestry::AncestryException)

Not sure why why this is coming up. I have been following the Ancestry railscast episode as well as the documentation.

This is also the same error I am getting when simply trying to run the rails console.

Here is the entire message:

/Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/ancestry-2.0.0/lib/ancestry/has_ancestry.rb:7:in `block in has_ancestry': Unknown option for has_ancestry: :hierarchy_class_name => "TagHierarchy". (Ancestry::AncestryException)
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/ancestry-2.0.0/lib/ancestry/has_ancestry.rb:5:in `each'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/ancestry-2.0.0/lib/ancestry/has_ancestry.rb:5:in `has_ancestry'
    from /Users/stevenbrooks1111/Code/freelance/GRN-Auth/config/initializers/tag_patch.rb:3:in `<class:Tag>'
    from /Users/stevenbrooks1111/Code/freelance/GRN-Auth/config/initializers/tag_patch.rb:2:in `<module:ActsAsTaggableOn>'
    from /Users/stevenbrooks1111/Code/freelance/GRN-Auth/config/initializers/tag_patch.rb:1:in `<top (required)>'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:245:in `load'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:245:in `block in load'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:245:in `load'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/engine.rb:588:in `block (2 levels) in <class:Engine>'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/engine.rb:587:in `each'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/engine.rb:587:in `block in <class:Engine>'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `instance_exec'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `run'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/initializable.rb:55:in `block in run_initializers'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `each'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `run_initializers'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/application.rb:136:in `initialize!'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/railtie/configurable.rb:30:in `method_missing'
    from /Users/stevenbrooks1111/Code/freelance/GRN-Auth/config/environment.rb:14:in `<top (required)>'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `block in require'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/application.rb:103:in `require_environment!'
    from /Users/stevenbrooks1111/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.11/lib/rails/commands.rb:40:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

Answer 1

One possible reason, which in my case was true, there are two different engines using ancestry and acts_as_tree. Engine1, requires ancestry in gemspec. Engine2, requires acts_as_tree in gemspec.

If engine1 is placed above engine2 in gemfile, ancestry gem is loaded first. In which case, this code executes and overrides acts_as_tree function. One way to fix this is put Engine2 over Engine1 in gemfile.

I haven't been able to figure out a better way to fix this, please let me know if you become aware of any.