Foreman with Katello is sometimes returning the error "Invalid single-table inheritance type: Organization is not a subclass of Taxonomy." It now happens almost every other hammer command for me on a dev environment. It has to do with Rails' DescendantTracker losing descendants of Taxonomy. I don't know what it means yet, but probably something with rails autoloading and Katello's taxonomy extensions.

From: /home/vagrant/.rvm/gems/ruby-2.4.1/gems/activerecord-5.1.6/lib/active_record/inheritance.rb @ line 203 ActiveRecord::Inheritance::ClassMethods#find_sti_class:

    187: def find_sti_class(type_name)
    188:   type_name = base_class.type_for_attribute(inheritance_column).cast(type_name)
    189:   subclass = begin
    190:     if store_full_sti_class
    191:       ActiveSupport::Dependencies.constantize(type_name)
    192:     else
    193:       compute_type(type_name)
    194:     end
    195:   rescue NameError
    196:     raise SubclassNotFound,
    197:       "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " \
    198:       "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " \
    199:       "Please rename this column if you didn't intend it to be used for storing the inheritance class " \
    200:       "or overwrite #{name}.inheritance_column to use another column for that information." 
    201:   end
    202:   unless subclass == self || descendants.include?(subclass)
 => 203:     require 'pry-remote'; binding.remote_pry
    204:     raise SubclassNotFound, "Invalid single-table inheritance type: #{subclass.name} is not a subclass of #{name}" 
    205:   end
    206:   subclass
    207: end

[1] pry(Taxonomy)> self
=> Taxonomy(id: integer, name: string, type: string, created_at: datetime, updated_at: datetime, ignore_types: text, description: text, label: string, ancestry: string, title: string, manifest_refreshed_at: datetime)
[2] pry(Taxonomy)> desendants
NameError: undefined local variable or method `desendants' for #<Class:0x0000000a4afce0>
Did you mean?  descendants
from /home/vagrant/.rvm/gems/ruby-2.4.1/gems/activerecord-5.1.6/lib/active_record/dynamic_matchers.rb:22:in `method_missing'
[3] pry(Taxonomy)> descendants
=> []
[4] pry(Taxonomy)> method(:descendants).source_location
=> ["/home/vagrant/.rvm/gems/ruby-2.4.1/gems/activesupport-5.1.6/lib/active_support/descendants_tracker.rb",
 56]
[5] pry(Taxonomy)> ActiveSupport::DescendantsTracker.descendants
ArgumentError: wrong number of arguments (given 0, expected 1)
from /home/vagrant/.rvm/gems/ruby-2.4.1/gems/activesupport-5.1.6/lib/active_support/descendants_tracker.rb:12:in `descendants'
[6] pry(Taxonomy)> ActiveSupport::DescendantsTracker.descendants(self)
=> []
[7] pry(Taxonomy)> Taxonomy.descendants
=> [Location(id: integer, name: string, type: string, created_at: datetime, updated_at: datetime, ignore_types: text, description: text, label: string, ancestry: string, title: string, manifest_refreshed_at: datetime),
 Organization(id: integer, name: string, type: string, created_at: datetime, updated_at: datetime, ignore_types: text, description: text, label: string, ancestry: string, title: string, manifest_refreshed_at: datetime)]