Issue with STI and namespaced Rails models

[wtn]

I tried creating a model called Catalog::Entry using closure_tree 6.0.0 and rails 4.2.6. Running rails generate closure_tree:migration Catalog::Entry or loading the app causes an exception. Here's the backtrace.

$ rails g closure_tree:migration Catalog::Entry
/project/lib/ruby/gems/2.2.0/gems/closure_tree-6.0.0/lib/closure_tree/active_record_support.rb:18:in `remove_prefix_and_suffix': undefined method `start_with?' for nil:NilClass (NoMethodError)
    from /project/lib/ruby/gems/2.2.0/gems/closure_tree-6.0.0/lib/closure_tree/support.rb:59:in `hierarchy_table_name'
    from /project/lib/ruby/gems/2.2.0/gems/closure_tree-6.0.0/lib/closure_tree/support.rb:50:in `hierarchy_class_for_model'
    from /project/lib/ruby/gems/2.2.0/gems/closure_tree-6.0.0/lib/closure_tree/has_closure_tree.rb:21:in `has_closure_tree'
    from /project/rails_app/app/models/catalog/entry.rb:3:in `<class:Entry>'
    from /project/rails_app/app/models/catalog/entry.rb:1:in `<top (required)>'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:457:in `load'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:457:in `block in load_file'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:647:in `new_constants_in'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:456:in `load_file'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:354:in `require_or_load'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:494:in `load_missing_constant'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:184:in `const_missing'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/inflector/methods.rb:263:in `const_get'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/inflector/methods.rb:263:in `block in constantize'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/inflector/methods.rb:259:in `each'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/inflector/methods.rb:259:in `inject'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/inflector/methods.rb:259:in `constantize'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/core_ext/string/inflections.rb:66:in `constantize'
    from /project/lib/ruby/gems/2.2.0/gems/closure_tree-6.0.0/lib/generators/closure_tree/migration_generator.rb:33:in `target_class'
    from /project/lib/ruby/gems/2.2.0/gems/closure_tree-6.0.0/lib/generators/closure_tree/migration_generator.rb:37:in `ct'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `block in invoke_all'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `each'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `map'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `invoke_all'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/group.rb:232:in `dispatch'
    from /project/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/generators.rb:157:in `invoke'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands/generate.rb:13:in `<top (required)>'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /project/lib/ruby/gems/2.2.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:130:in `generate_or_destroy'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:50:in `generate'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /project/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

[wtn]

I was able to work around the issue by declaring the class abstract after invoking has_closure_tree.

has_closure_tree
self.abstract_class = true # no exception

Maybe something for the documentation?

[seuros]

Thanks for sharing the solution!