Revert "Merge pull request solidusio#3998 from nebulab/kennyadsl/fix-…

…preferences-serialization"

This reverts commit bcea9e1, reversing
changes made to a9a7a95.

core/app/models/spree/base.rb

@@ -5,10 +5,6 @@ class Spree::Base < ActiveRecord::Base
   include Spree::Core::Permalinks
   include Spree::RansackableAttributes
 
-  def preferences
-    read_attribute(:preferences) || self.class.preferences_coder_class.new
-  end
-
   def initialize_preference_defaults
     if has_attribute?(:preferences)
       self.preferences = default_preferences.merge(preferences)
@@ -20,15 +16,11 @@ def initialize_preference_defaults
   def self.preference(*args)
     # after_initialize can be called multiple times with the same symbol, it
     # will only be called once on initialization.
-    serialize :preferences, preferences_coder_class
+    serialize :preferences, Hash
     after_initialize :initialize_preference_defaults
     super
   end
 
-  def self.preferences_coder_class
-    Hash
-  end
-
   self.abstract_class = true
 
   # Provides a scope that should be included any time products

core/spec/models/spree/stock/estimator_spec.rb

@@ -96,24 +96,6 @@ module Stock
         context "general shipping methods" do
           before { Spree::ShippingMethod.all.each(&:destroy) }
 
-          context 'with a custom shipping calculator with no preference' do
-            class Spree::Calculator::Shipping::NoPreferences < Spree::ShippingCalculator
-              def compute_package(_package)
-                # no op
-              end
-            end
-
-            let!(:shipping_methods) do
-              [
-                create(:shipping_method, calculator: Spree::Calculator::Shipping::NoPreferences.new)
-              ]
-            end
-
-            it 'does not raise an error' do
-              expect { subject.shipping_rates(package) }.not_to raise_error
-            end
-          end
-
           context 'with two shipping methods of different cost' do
             let!(:shipping_methods) do
               [