This issue will surface for many who depend on Ruby’s JSON serialization outside of

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Asked: June 17, 20262026-06-17T06:29:56+00:00 2026-06-17T06:29:56+00:00

This issue will surface for many who depend on Ruby’s JSON serialization outside of

0

This issue will surface for many who depend on Ruby’s JSON serialization outside of a Rails projects. When they try to use their code in a Rails project, it will not work as expected.

The following code run from Ruby (no Rails), prints A.
When run from rails console, it prints Hash.

That means my json serialization works in my command line lib/app, but not when it’s imported into a Rails project.

What is the reason/workaround for this?

require 'json'

class A
  def to_json(*a)
    {:json_class => self.class.name}.to_json(*a)
  end
  def self.json_create(o)
    A.new
  end
end

class B
  attr_accessor :value
  def initialize(value)
    @value = value
  end

  def to_json(*a)
    {:json_class => self.class.name, :value => value}.to_json(*a)
  end
  def self.json_create(o)
    B.new(o['value'])
  end
end
b = JSON.parse(B.new(A.new).to_json)
puts b.value.class

Ruby is 1.9.3, Rails is 3.2.10