Hashie::Mash is coerced into Hash

[Domon]

Hi,

I am surprised that that Hashie::Mash is coerced into Hash.

Is this expected behavior? If so, how can I avoid it?

Thanks! :smiley:

Example:

require 'virtus'
require 'hashie'

class User
  include Virtus.model

  attribute :preferences, Hashie::Mash
end

preferences = Hashie::Mash.new({ foo: 1, bar: 2 })
puts "preferences = #{preferences.inspect}"

user = User.new(preferences: preferences)

puts "user.preferences = #{user.preferences.inspect}"
puts "user.preferences is a #{user.preferences.class}"

Output:

preferences = #<Hashie::Mash bar=2 foo=1>
user.preferences = {"foo"=>1, "bar"=>2}
user.preferences is a Hash

[neumachen]

Have you tried making your own custom coercion? Or setting the coercion to that attribute to false?

attribute :preferences, Hashie::Mash, coerce: false

It is also possible that Hashie::Mash returns a hash class but with extended methods from Hashie::Mash.

[Domon]

Hi @magicalbanana,

Thanks for the comments!

coerce: false prevents the coercion, but I wonder if there are something that should be fixed.

What do you mean by "Hashie::Mash returns a hash class"? Do you have a specific name of a method on Hashie::Mash in mind?

[neumachen]

@Domon I mean it is possible that Hashie::Mash's return class/object is a Hash class. You can look at whatever method you may be using to determine that. Look at Hashie's source code and see.

I am not too familiar with Hashie but I know it either returns a Hashie object which is a Hash eitherway. If you want to keep your coercion strict, you may want to look at custom value coercion with Virtus.