no migration will be added if model and column is exists

Gemfile

@@ -3,4 +3,4 @@ source "https://rubygems.org"
 gemspec
 
 gem 'sqlite3',                          :platforms => :ruby
-gem 'rails', '5.1.4'
+gem 'rails', '5.1.4'

aasm.gemspec

@@ -23,10 +23,11 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec', ">= 3"
   s.add_development_dependency 'generator_spec'
   s.add_development_dependency 'appraisal'
-
+  
   # debugging
   # s.add_development_dependency 'debugger'
   s.add_development_dependency 'pry'
+  s.add_development_dependency 'pry-nav'
 
   s.files         = `git ls-files`.split("\n")
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")

lib/generators/aasm/orm_helpers.rb

@@ -22,6 +22,12 @@ RUBY
 
       private
 
+      def column_exists?
+        table_name.singularize.humanize.constantize.column_names.include?(column_name.to_s)
+      rescue NameError
+        false
+      end
+
       def model_exists?
         File.exists?(File.join(destination_root, model_path))
       end

lib/generators/active_record/aasm_generator.rb

@@ -11,7 +11,9 @@ module ActiveRecord
       source_root File.expand_path("../templates", __FILE__)
 
       def copy_aasm_migration
-        if model_exists?
+        if column_exists?
+          puts "Both model and column exists"
+        elsif model_exists?
           migration_template "migration_existing.rb", "db/migrate/add_#{column_name}_to_#{table_name}.rb"
         else
           migration_template "migration.rb", "db/migrate/aasm_create_#{table_name}.rb"

spec/database.rb

@@ -20,6 +20,10 @@ ActiveRecord::Migration.suppress_messages do
     t.string "right"
   end
 
+  ActiveRecord::Migration.create_table "jobs", :force => true do |t|
+    t.string "state"
+  end
+
   %w(validators multiple_validators workers invalid_persistors multiple_invalid_persistors silent_persistors multiple_silent_persistors).each do |table_name|
     ActiveRecord::Migration.create_table table_name, :force => true do |t|
       t.string "name"

spec/generators/active_record_generator_spec.rb

@@ -43,5 +43,11 @@ if defined?(ActiveRecord)
       assert_migration "db/migrate/add_state_to_jobs.rb"
     end
 
+    it "dont add column if column is already exists" do
+      require 'models/active_record/job.rb'
+      load_schema
+      run_generator %w(job state)
+      assert_no_migration "db/migrate/add_state_to_jobs.rb"
+    end
   end
 end

spec/models/active_record/job.rb

@@ -0,0 +1,3 @@
+class Job < ActiveRecord::Base
+  include AASM
+end

spec/spec_helper.rb

@@ -13,6 +13,7 @@ SEQUEL_DB = defined?(JRUBY_VERSION) ? 'jdbc:sqlite::memory:' : 'sqlite:/'
 
 def load_schema
   require 'logger'
+  require 'yaml'
   config = YAML::load(IO.read(File.dirname(__FILE__) + '/database.yml'))
   ActiveRecord::Base.logger = Logger.new(File.dirname(__FILE__) + "/debug.log")
   ActiveRecord::Base.establish_connection(config['sqlite3'])