Maintenance: Reduce HasBackends overhead by autoloading backends on initialisation.

app/models/object_manager/attribute/validation/backend.rb

@@ -1,10 +1,4 @@
 class ObjectManager::Attribute::Validation::Backend
-  include Mixin::IsBackend
-
-  def self.inherited(subclass)
-    subclass.is_backend_of(::ObjectManager::Attribute::Validation)
-  end
-
   def self.validate(*args)
     new(*args).validate
   end
@@ -22,5 +16,3 @@ class ObjectManager::Attribute::Validation::Backend
     record.errors.add attribute.name.to_sym, message
   end
 end
-
-Mixin::RequiredSubPaths.eager_load_recursive(__dir__)

lib/mixin/has_backends.rb

@@ -7,7 +7,14 @@ module Mixin
         Set.new
       end
 
-      require_dependency "#{name}::Backend".underscore
+      self_path     = ActiveSupport::Dependencies.search_for_file name.underscore
+      backends_path = self_path.delete_suffix File.extname(self_path)
+
+      Mixin::RequiredSubPaths.eager_load_recursive backends_path
+
+      backends = "#{name}::Backend".constantize.descendants
+
+      self.backends = Set.new(backends)
     end
   end
 end

lib/mixin/is_backend.rb

@@ -1,12 +0,0 @@
-module Mixin
-  module IsBackend
-    extend ActiveSupport::Concern
-
-    class_methods do
-
-      def is_backend_of(klass) # rubocop:disable Naming/PredicateName
-        klass.backends.add(self)
-      end
-    end
-  end
-end

lib/secure_mailing/backend.rb

@@ -1,9 +1,2 @@
 class SecureMailing::Backend
-  include Mixin::IsBackend
-
-  def self.inherited(subclass)
-    subclass.is_backend_of(::SecureMailing)
-  end
 end
-
-Mixin::RequiredSubPaths.eager_load_recursive(__dir__)

spec/models/object_manager/attribute/validation/backend_examples.rb

@@ -2,6 +2,7 @@ require 'rails_helper'
 
 RSpec.shared_examples 'a validation without errors' do
   it 'validatates without errors' do
+    allow(subject).to receive(:value).and_return(value) # rubocop:disable RSpec/SubjectStub
     subject.validate
     expect(record.errors).to be_blank
   end
@@ -9,7 +10,14 @@ end
 
 RSpec.shared_examples 'a validation with errors' do
   it 'validates with errors' do
+    allow(subject).to receive(:value).and_return(value) # rubocop:disable RSpec/SubjectStub
     subject.validate
     expect(record.errors).to be_present
   end
 end
+
+RSpec.shared_examples 'validate backend' do
+  it 'included in backends list' do
+    expect(::ObjectManager::Attribute::Validation.backends).to include(described_class)
+  end
+end

spec/models/object_manager/attribute/validation/backend_spec.rb

@@ -2,13 +2,6 @@ require 'rails_helper'
 
 RSpec.describe ObjectManager::Attribute::Validation::Backend do
 
-  it 'registers inheriting classes as ObjectManager::Attribute::Validation backends' do
-    backends = spy
-    expect(ObjectManager::Attribute::Validation).to receive(:backends).and_return(backends)
-    backend = Class.new(described_class)
-    expect(backends).to have_received(:add).with(backend)
-  end
-
   describe 'backend interface' do
 
     subject do

spec/models/object_manager/attribute/validation/future_past_spec.rb

@@ -13,9 +13,7 @@ RSpec.describe ::ObjectManager::Attribute::Validation::FuturePast do
   let(:record) { build(:user) }
   let(:attribute) { build(:object_manager_attribute_datetime) }
 
-  before do
-    allow(subject).to receive(:value).and_return(value)
-  end
+  it_behaves_like 'validate backend'
 
   shared_examples 'data_option validator' do |data_option:, value:|
     context "for data_option '#{data_option}'" do

spec/models/object_manager/attribute/validation/min_max_spec.rb

@@ -13,9 +13,7 @@ RSpec.describe ::ObjectManager::Attribute::Validation::MinMax do
   let(:record) { build(:user) }
   let(:attribute) { build(:object_manager_attribute_integer) }
 
-  before do
-    allow(subject).to receive(:value).and_return(value) # rubocop:disable RSpec/SubjectStub, RSpec/NamedSubject
-  end
+  it_behaves_like 'validate backend'
 
   context 'when validation should not be performed' do
 

spec/models/object_manager/attribute/validation/required_spec.rb

@@ -13,9 +13,7 @@ RSpec.describe ::ObjectManager::Attribute::Validation::Required do
   let(:record) { build(:user) }
   let(:attribute) { build(:object_manager_attribute_date) }
 
-  before do
-    allow(subject).to receive(:value).and_return(value)
-  end
+  it_behaves_like 'validate backend'
 
   context 'when validation should be performed' do