CODEWITHSUNDEEP
ruby-on-railsrubyactiverecord
harika
harika

Reputation: 113

ActiveRecord::ActiveRecordError (cannot touch on a new record object) rails 4

I recently upgraded a rails 3 application to rails 4. When I am trying to create a new Test, below code from before_save fails to execute. The same code works fine with rails 3.

class Test < ActiveRecord::Base
  has_many  :assignments, :dependent => :destroy

  before_save do
    if code_changed? 
      self.assignments.each{|a| a.touch}
    end
  end
end

class Assignment < ActiveRecord::Base
  belongs_to :test, :touch => true
end

I see the below error when I create a new test.

ActiveRecord::ActiveRecordError (cannot touch on a new record object):
app/models/test.rb:6:in `block (2 levels) in <class:Test>'
app/models/test.rb:6:in `block in <class:Test>'
app/controllers/tests_controller.rb:423:in `create'

Any suggestions to resolve this issue ??

Upvotes: 2

Views: 1838

Answers (2)

Leo Van Deuren
Leo Van Deuren

Reputation: 435

It is because your function that is before save needs to be private. And you can restructure it like this for readability.

class Test < ActiveRecord::Base
  has_many  :assignments, :dependent => :destroy
  before_save :before_save_function
        
  private

  def before_save_function
    if code_changed? 
      self.assignments.each{|a| a.touch}
    end
  end
end

Cheers! Hope it Helps.

Upvotes: 0

Naren Sisodiya
Naren Sisodiya

Reputation: 7288

The error is raised because there is a new assignment object and not saved in the database. The touch can not be called on new record.

Just check for new_record? before calling touch. 

before_save do
 if code_changed? 
     self.assignments.each{|a| a.touch unless a.new_record?}
  end
end

Upvotes: 3

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