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#2753 ✓resolved
Cody Fauser

#to_json behavior still different between Rails and Rails 2-3-stable

Reported by Cody Fauser | June 3rd, 2009 @ 04:17 PM | in 2.3.3

Ticket #2690 helped the problems with to_json serialization in the Rails 2.3 branch, but the behavior of to_json is still different between Rails and Rails 2.3-stable. The following example illustrates the problem:

class A
  def initialize
    @a, @b = 1, 2
  def to_json(options = {})

class B
  def initialize
    @a =

In Rails the output is the following:

b =
b.to_json #=> {"a": 1}

In Rails 2.3-stable the output is:

b =
b.to_json #=> {"a":{"a":1,"b":2}}

The problem is caused by ActiveSupport::JSON.encode calling rails_to_json instead of to_json on the objects. Overridden to_json() methods child objects are never called.

Going forward all objects will have to have a rails_to_json() method, but the problem is that this functionality changed in the stable 2-3 branch.

In Shopify we have monkey patched active_support/json/encoding.rb to call value.to_json() instead of value.rails_to_json() to achieve the same output from Rails

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