Cross-migration dependency

migration-1.rb

class Migration1 < ActiveRecord::Migration
  def change
    add_column :models, :test_1, :integer
    
    Model.update_first
  end
end

migration-2.rb

class Migration1 < ActiveRecord::Migration
  def change
    add_column :models, :test_2, :integer
  end
end

model.rb

# at the time of writing migration 1
class Model < ActiveRecord::Base
  def self.update_first
    Model.first.update_attributes!(test_1: 1)
  end
end


# at the time of writing migration 2
class Model < ActiveRecord::Base
  def self.do_something
    Model.first.update_attributes!(test_1: 1, test_2: 2)
  end
end

# when these two separate changes get merged together
# migration 1 will fail because the code already
# references the attribute test_2