Add missing class and allow extending serializable classes on logs

`Spree::LogEntry` loads details from a YAML string that can potentially
contain any serialized Ruby object if users have overridden some part of
the codebase.

New Psych (YAML parser) version packed with Ruby 3.1 requires that, by
default, users are explicit about which type of classes are allowed to
be loaded (see ruby/psych@cb50aa8 and ruby/psych@1764942).

On 008168c, we updated our code to allow instances of
`ActiveMerchant::Billing::Response`. However, as [noted in a
comment](solidusio@008168c#r73483078),
it seems we're missing, at least, instances of
`ActiveSupport::TimeWithZone`.

We need to add all classes used internally and leave a door open for
users to add their own classes (via a new `log_entry_permitted_classes`
preference).

core/app/models/spree/log_entry.rb

@@ -2,10 +2,53 @@
 
 module Spree
  class LogEntry < Spree::Base
+ # Classes used in core that can be present in serialized details
+ #
+ # Users can add their own classes in
+ # `Spree::Config#log_entry_permitted_classes`.
+ #
+ # @see Spree::AppConfiguration#log_entry_permitted_classes
+ CORE_PERMITTED_CLASSES = [
+ ActiveMerchant::Billing::Response,
+ ActiveSupport::TimeWithZone,
+ Time,
+ ActiveSupport::TimeZone
+ ].freeze
+
+ # Raised when a disallowed class is tried to be loaded
+ class DisallowedClass < RuntimeError
+ attr_reader :psych_exception
+
+ def initialize(psych_exception:)
+ @psych_exception = psych_exception
+ super(default_message)
+ end
+
+ private
+
+ def default_message
+ <<~MSG
+ #{psych_exception.message}
+
+ You can specify custom classes to be loaded in config/initializers/spree.rb. E.g:
+
+ Spree.config do |config|
+ config.log_entry_permitted_classes = ['MyClass']
+ end
+ MSG
+ end
+ end
+
+ def self.permitted_classes
+ CORE_PERMITTED_CLASSES + Spree::Config.log_entry_permitted_classes.map(&:constantize)
+ end
+
  belongs_to :source, polymorphic: true, optional: true
 
  def parsed_details
- @details ||= YAML.safe_load(details, permitted_classes: [ActiveMerchant::Billing::Response])
+ @details ||= YAML.safe_load(details, permitted_classes: self.class.permitted_classes)
+ rescue Psych::DisallowedClass => e
+ raise DisallowedClass.new(psych_exception: e)
  end
  end
 end

core/lib/spree/app_configuration.rb

@@ -170,6 +170,15 @@ class AppConfiguration < Preferences::Configuration
  # @return [String] URL of logo used on frontend (default: +'logo/solidus.svg'+)
  preference :logo, :string, default: 'logo/solidus.svg'
 
+ # @!attribute [rw] log_entry_permitted_classes
+ # @return [Array<String>] An array of extra classes that are allowed to be
+ # loaded from a serialized YAML as details in {Spree::LogEntry}
+ # (defaults to a non-frozen empty array, so that extensions can add
+ # their own classes).
+ # @example
+ # config.log_entry_permitted_classes = ['Date']
+ preference :log_entry_permitted_classes, :array, default: []
+
  # @!attribute [rw] mails_from
  # @return [String] Email address used as +From:+ field in transactional emails.
  preference :mails_from, :string, default: '[email protected]'

core/spec/models/spree/log_entry_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Spree::LogEntry, type: :model do
+ describe '#parsed_details' do
+ it 'can parse ActiveMerchant::Billing::Response instances' do
+ response = ActiveMerchant::Billing::Response.new('success', 'message')
+
+ log_entry = described_class.new(details: response.to_yaml)
+
+ expect { log_entry.parsed_details }.not_to raise_error
+ end
+
+ it 'can parse ActiveSupport::TimeWithZone instances' do
+ time = Time.zone.now
+
+ log_entry = described_class.new(details: time.to_yaml)
+
+ expect { log_entry.parsed_details }.not_to raise_error
+ end
+
+ it 'can parse user specified classes instances' do
+ stub_spree_preferences(log_entry_permitted_classes: ['Date'])
+
+ log_entry = described_class.new(details: Date.today)
+
+ expect { log_entry.parsed_details }.not_to raise_error
+ end
+
+ it 'raises a meaningful exception when a disallowed class is found' do
+ log_entry = described_class.new(details: Date.today)
+
+ expect { log_entry.parsed_details }.to raise_error(described_class::DisallowedClass, /log_entry_permitted_classes/)
+ end
+ end
+end