g agile web development with rails 4

I need your help.
My Ruby on Rails tutorial(agile web development with rails 4, block g) gives me an error. I am new to Ruby and have no idea how to fix it.

Source :

class CombineItemsInCart < ActiveRecord::Migration
    def up

      Cart.all.each do |cart|
        # how many goods are in the cart?
        sums = cart.line_items.group(:product_id).sum(:quantity)
        sums.each do |product_id; quantity|
          if quantity > 1
            # remove lines
            cart.line_items.where(:product_id product_id).delete_all

            # replace with a one line
            item = cart.line_items.build(product_id: product_id)
            item.quantity = quantity
            item.save!
          end
       end
    end
  end
end

The error is:

Migrations are pending; run 'rake db:migrate RAILS_ENV=development' to resolve this issue.

But when I tried to run rake db:migrate ,
I receive this error in terminal:

rake db:migrate RAILS_ENV=development

rake aborted! SyntaxError: /home/yury/Desktop/rails/depot_g/db/migrate/20170401195439_combine_items_in_cart.rb:10: syntax error, unexpected tIDENTIFIER, expecting ')' cart.line_items.where(:product_id product_id).delete_all ^ /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in require' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in block in require' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in load_dependency' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in require' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:718:in load_migration' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:714:in migration' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:70 8:in disable_ddl_transaction' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:1012:in use_transaction?' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:1004:in ddl_transaction' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:958:in execute_migration_in_transaction' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:920:in block in migrate' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:916:in each' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:916:in migrate' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:764:in up' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/migration.rb:742:in migrate' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/activerecord-4.0.0/lib/active_record/railties/databases.rake:42:in block (2 levels) in ' /home/yury/.rvm/gems/ruby-2.0.0-p648/gems/rake-12.0.0/exe/rake:27:in <top (required)>' /home/yury/.rvm/gems/ruby-2.0.0-p648/bin/ruby_executable_hooks:15:in <top (required)>' /home/yury/.rvm/gems/ruby-2.0.0-p648/bin/ruby_executable_hooks:15:in eval' /home/yury/.rvm/gems/ruby-2.0.0-p648/bin/ruby_executable_hooks:15:in `' Tasks: TOP => db:migrate (See full trace by running task with --trace)

System: Ubuntu 16.04 64 bit. I checked the code few times and it is the same as in the book.

So could anyone help me and tell what I am doing wrong? And how can I fix it? Thanks!

---

As it says " syntax error, unexpected tIDENTIFIER, expecting ')' " then there's a typo in your code syntax and is in your sums.each block, change

sums.each do |product_id; quantity|

For

sums.each do |product_id, quantity|

And in your if statement from this

cart.line_items.where(:product_id product_id)

To this

cart.line_items.where(product_id: product_id)

Check the original code from the book:

# rails40/depot_g/db/migrate/20121130000005_combine_items_in_cart.rb
def up
  # replace multiple items for a single product in a cart with a single item
  Cart.all.each do |cart|
    # count the number of each product in the cart
    sums = cart.line_items.group(:product_id).sum(:quantity)
    sums.each do |product_id, quantity|
      if quantity > 1
        # remove individual items
        cart.line_items.where(product_id: product_id).delete_all
        # replace with a single item
        item = cart.line_items.build(product_id: product_id)
        item.quantity = quantity
        item.save!
      end
    end
  end
end

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