Defer constant loading of ActiveRecord::DestroyAssociationAsyncJob via a String instead of a class constant

activejob/lib/active_job/railtie.rb

@@ -41,10 +41,6 @@ class Railtie < Rails::Railtie # :nodoc:
       ActiveSupport.on_load(:action_dispatch_integration_test) do
         include ActiveJob::TestHelper
       end
-
-      ActiveSupport.on_load(:active_record) do
-        self.destroy_association_async_job ||= ActiveRecord::DestroyAssociationAsyncJob
-      end
     end
 
     initializer "active_job.set_reloader_hook" do |app|

activerecord/CHANGELOG.md

@@ -1,3 +1,16 @@
+*   Allow `destroy_association_async_job=` to be configured with a class string instead of a constant.
+
+    Defers an autoloading dependency between `ActiveRecord::Base` and `ActiveJob::Base`
+    and moves the configuration of `ActiveRecord::DestroyAssociationAsyncJob`
+    from ActiveJob to ActiveRecord.
+
+    Deprecates `ActiveRecord::ActiveJobRequiredError` and now raises a `NameError`
+    if the job class is unloadable or an `ActiveRecord::ConfigurationError` if
+    `dependent: :destroy_async` is declared on an association but there is no job
+    class configured.
+
+    *Ben Sheldon*
+
 *   Fix `ActiveRecord::Store` to serialize as a regular Hash
 
     Previously it would serialize as an `ActiveSupport::HashWithIndifferentAccess`
@@ -16,7 +29,7 @@
     ```
 
     *Alex Ghiculescu*
-    
+
 *   Add new `ActiveRecord::Base::generates_token_for` API.
 
     Currently, `signed_id` fulfills the role of generating tokens for e.g.
@@ -49,7 +62,7 @@
     user.update!(password: "new password")
     User.find_by_token_for(:password_reset, token) # => nil
     ```
-    
+
     *Jonathan Hefner*
 
 *   Optimize Active Record batching for whole table iterations.

activerecord/lib/active_record/associations/builder/association.rb

@@ -128,8 +128,8 @@ def self.valid_dependent_options
 
     def self.check_dependent_options(dependent, model)
       if dependent == :destroy_async && !model.destroy_association_async_job
-        err_message = "ActiveJob is required to use destroy_async on associations"
-        raise ActiveRecord::ActiveJobRequiredError, err_message
+        err_message = "A valid destroy_association_async_job is required to use `dependent: :destroy_async` on associations"
+        raise ActiveRecord::ConfigurationError, err_message
       end
       unless valid_dependent_options.include? dependent
         raise ArgumentError, "The :dependent option must be one of #{valid_dependent_options}, but is :#{dependent}"

activerecord/lib/active_record/core.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "active_support/core_ext/enumerable"
+require "active_support/core_ext/module/delegation"
 require "active_support/core_ext/string/filters"
 require "active_support/parameter_filter"
 require "concurrent/map"
@@ -19,11 +20,20 @@ module Core
       # retrieved on both a class and instance level by calling +logger+.
       class_attribute :logger, instance_writer: false
 
-      ##
-      # :singleton-method:
-      #
-      # Specifies the job used to destroy associations in the background
-      class_attribute :destroy_association_async_job, instance_writer: false, instance_predicate: false, default: false
+      class_attribute :_destroy_association_async_job, instance_accessor: false, default: "ActiveRecord::DestroyAssociationAsyncJob"
+
+      # The job class used to destroy associations in the background.
+      def self.destroy_association_async_job
+        if _destroy_association_async_job.is_a?(String)
+          self._destroy_association_async_job = _destroy_association_async_job.constantize
+        end
+        _destroy_association_async_job
+      rescue NameError => error
+        raise NameError, "Unable to load destroy_association_async_job: #{error.message}"
+      end
+
+      singleton_class.alias_method :destroy_association_async_job=, :_destroy_association_async_job=
+      delegate :destroy_association_async_job, to: :class
 
       ##
       # :singleton-method:

activerecord/lib/active_record/errors.rb

@@ -7,9 +7,12 @@ module ActiveRecord
   class ActiveRecordError < StandardError
   end
 
-  # Raised when trying to use a feature in Active Record which requires Active Job but the gem is not present.
-  class ActiveJobRequiredError < ActiveRecordError
-  end
+  # DEPRECATED: Previously raised when trying to use a feature in Active Record which
+  # requires Active Job but the gem is not present. Now raises a NameError.
+  include ActiveSupport::Deprecation::DeprecatedConstantAccessor
+  DeprecatedActiveJobRequiredError = Class.new(ActiveRecordError) # :nodoc:
+  deprecate_constant "ActiveJobRequiredError", "ActiveRecord::DeprecatedActiveJobRequiredError",
+    message: "ActiveRecord::ActiveJobRequiredError has been deprecated. If Active Job is not present, a NameError will be raised instead."
 
   # Raised when the single-table inheritance mechanism fails to locate the subclass
   # (for example due to improper usage of column that

activerecord/test/activejob/destroy_association_async_job_test.rb

@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class UndefinedConstantAsync < ActiveRecord::Base
+  self.destroy_association_async_job = "UndefinedConstantJob"
+end
+
+autoload :UnloadableBaseJob, "activejob/unloadable_base_job"
+class UnloadableBaseAsync < ActiveRecord::Base
+  self.destroy_association_async_job = "UnloadableBaseJob"
+end
+
+class UnusedBelongsToAsync < ActiveRecord::Base
+  self.destroy_association_async_job = nil
+end
+
+class UnusedHasOneAsync < ActiveRecord::Base
+  self.destroy_association_async_job = nil
+end
+
+class UnusedHasManyAsync < ActiveRecord::Base
+  self.destroy_association_async_job = nil
+end
+
+
+class DestroyAssociationAsyncJobTest < ActiveRecord::TestCase
+  test "destroy_association_async_job requires valid job class" do
+    error = assert_raises NameError do
+      UndefinedConstantAsync.belongs_to :essay_destroy_async, dependent: :destroy_async
+    end
+    assert_match %r/destroy_association_async_job: uninitialized constant UndefinedConstantJob/, error.message
+  end
+
+  test "destroy_association_async_job error shows a missing parent job class, as if ActiveJob were missing" do
+    error = assert_raises NameError do
+      UnloadableBaseAsync.belongs_to :essay_destroy_async, dependent: :destroy_async
+    end
+    assert_match %r/destroy_association_async_job: uninitialized constant PretendActiveJobIsNotPresent/, error.message
+  end
+
+  test "deprecation of rescuing ActiveJobRequiredError which has been replaced by a NameError" do
+    assert_deprecated { ActiveRecord::ActiveJobRequiredError }
+  end
+
+  test "belong_to dependent destroy_async requires destroy_association_async_job" do
+    error = assert_raises ActiveRecord::ConfigurationError do
+      UnusedBelongsToAsync.belongs_to :essay_destroy_async, dependent: :destroy_async
+    end
+    assert_match %r/destroy_association_async_job/, error.message
+  end
+
+  test "has_one dependent destroy_async requires destroy_association_async_job" do
+    error = assert_raises ActiveRecord::ConfigurationError do
+      UnusedHasOneAsync.has_one :essay_destroy_async, dependent: :destroy_async
+    end
+    assert_match %r/destroy_association_async_job/, error.message
+  end
+
+  test "has_many dependent destroy_async requires destroy_association_async_job" do
+    error = assert_raises ActiveRecord::ConfigurationError do
+      UnusedHasManyAsync.has_many :essay_destroy_asyncs, dependent: :destroy_async
+    end
+    assert_match %r/destroy_association_async_job/, error.message
+  end
+end

activerecord/test/activejob/unloadable_base_job.rb

@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+class UnloadableBaseJob < PretendActiveJobIsNotPresent; end

railties/test/application/configuration_test.rb

@@ -2666,12 +2666,12 @@ class ::DummySerializer < ActiveJob::Serializers::ObjectSerializer; end
       assert_equal ActiveRecord::DestroyAssociationAsyncJob, ActiveRecord::Base.destroy_association_async_job
     end
 
-    test "ActiveRecord::Base.destroy_association_async_job can be configured via config.active_record.destroy_association_job" do
+    test "ActiveRecord::Base.destroy_association_async_job can be configured via config.active_record.destroy_association_async_job" do
       class ::DummyDestroyAssociationAsyncJob; end
 
       app_file "config/environments/test.rb", <<-RUBY
         Rails.application.configure do
-          config.active_record.destroy_association_async_job = DummyDestroyAssociationAsyncJob
+          config.active_record.destroy_association_async_job = "DummyDestroyAssociationAsyncJob"
         end
       RUBY