Do not overwrite AJ logger if it is supplied

Use conditional assignment within 'active_job.logger' initializer

activejob/lib/active_job/railtie.rb

@@ -15,7 +15,7 @@ module ActiveJob
     end
 
     initializer "active_job.logger" do
-      ActiveSupport.on_load(:active_job) { self.logger = ::Rails.logger }
+      ActiveSupport.on_load(:active_job) { self.logger ||= ::Rails.logger }
     end
 
     initializer "active_job.custom_serializers" do |app|

activejob/test/cases/railtie_test.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "helper"
+require "active_support/testing/isolation"
+
+class RailtieTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  setup do
+    require "rails"
+
+    rails_logger = Logger.new(nil)
+
+    @app ||= Class.new(::Rails::Application) do
+      def self.name; "AJRailtieTestApp"; end
+
+      config.eager_load = false
+      config.logger = rails_logger
+      config.active_support.cache_format_version = 7.1
+    end
+  end
+
+  test "active_job.logger initializer does not overwrite the supplied logger" do
+    custom_logger = Logger.new(nil)
+
+    @app.config.before_initialize do |app|
+      ActiveSupport.on_load(:active_job) do
+        self.logger = custom_logger
+      end
+    end
+
+    require "active_job/railtie"
+    @app.initialize!
+
+    assert_same ActiveJob::Base.logger, custom_logger
+  end
+end