Merge pull request #325 from voormedia/pr-304

Rebase of #304 - Handle paper_trail's custom version classes.

lib/rails_erd/domain.rb

@@ -140,8 +140,7 @@ def check_association_validity(association)
       association.check_validity!
 
       if association.options[:polymorphic]
-        entity_name = association.class_name
-        entity_by_name(entity_name) or raise "polymorphic interface #{entity_name} does not exist"
+        check_polymorphic_association_validity(association)
       else
         entity_name = association.klass.name # Raises NameError if the associated class cannot be found.
         entity_by_name(entity_name) or raise "model #{entity_name} exists, but is not included in domain"
@@ -150,6 +149,17 @@ def check_association_validity(association)
       warn "Ignoring invalid association #{association_description(association)} (#{e.message})"
     end
 
+    def check_polymorphic_association_validity(association)
+      entity_name = association.class_name
+      entity = entity_by_name(entity_name)
+
+      if entity || (entity && entity.generalized?)
+        return entity
+      else
+        raise("polymorphic interface #{entity_name} does not exist")
+      end
+    end
+
     def association_description(association)
       "#{association.name.inspect} on #{association.active_record}"
     end

rails-erd.gemspec

@@ -18,6 +18,8 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency "ruby-graphviz", "~> 1.2"
   s.add_runtime_dependency "choice", "~> 0.2.0"
 
+  s.add_development_dependency "pry"
+
   s.files         = `git ls-files -- {bin,lib,test}/* CHANGES.rdoc LICENSE Rakefile README.md`.split("\n")
   s.test_files    = `git ls-files -- test/*`.split("\n")
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }

test/test_helper.rb

@@ -1,5 +1,6 @@
 require "rubygems"
 require "bundler/setup"
+require 'pry'
 
 require "active_record"