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  1. Mongoid
  2. MONGOID-1879

Fields reset to defaults on save when omitted by .only()

    • Type: Icon: Task Task
    • Resolution: Done
    • 2.4.8
    • Affects Version/s: None
    • Component/s: None
    • Labels:

      If you use Criteria#only to only return some fields from the database and then save a returned document, any fields not loaded will be set to their default values.

      I am using Mongoid 2.4.7, Rails 3.2.2, and Mongodb 2.0.2.

      Here is an example that demonstrates this:

      class Widget
        include Mongoid::Document
        
        field :color, :type => String, :default => "blue"
        field :price, :type => Integer
      end
      
      Widget.delete_all
      Widget.create!(:color => "red", :price => 1)
      Widget.create!(:color => "green", :price => 2)
      
      puts "Initial state, colors are red and green:"
      Widget.all.each {|w| puts w.inspect}
      
      Widget.all.only(:price).each do |w|
        w.price += 10
        w.save!
      end
      
      puts "\nAll colors have changed to blue after update:"
      Widget.all.each {|w| puts w.inspect}
      

      Here is the output of the script:

      Unable to find source-code formatter for language: code. Available languages are: actionscript, ada, applescript, bash, c, c#, c++, cpp, css, erlang, go, groovy, haskell, html, java, javascript, js, json, lua, none, nyan, objc, perl, php, python, r, rainbow, ruby, scala, sh, sql, swift, visualbasic, xml, yaml
      Initial state, colors are red and green:
      #<Widget _id: 4f75d743acb93e02ac000001, price: 1, color: "red", _type: nil>
      #<Widget _id: 4f75d743acb93e02ac000002, price: 2, color: "green", _type: nil>
      
      All colors have changed to blue after update:
      #<Widget _id: 4f75d743acb93e02ac000001, price: 11, color: "blue", _type: nil>
      #<Widget _id: 4f75d743acb93e02ac000002, price: 12, color: "blue", _type: nil>
      

      Appears to be related to MONGOID-1643. Although the exact repro steps described in that issue no longer trigger this problem, calling to_a or iterating over the elements as in the example above still expose the problem.

            Assignee:
            Unassigned Unassigned
            Reporter:
            nkriege nkriege
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              Created:
              Updated:
              Resolved: