Merge pull request rails#49462 from Edouard-chin/ec-broadcast-prevent

Handle case when `config.logger` is already a BroadcastLogger:

Author: eugeneius

railties/lib/rails/application/bootstrap.rb

@@ -56,9 +56,11 @@ module Bootstrap
         end
         Rails.logger.level = ActiveSupport::Logger.const_get(config.log_level.to_s.upcase)
 
-        broadcast_logger = ActiveSupport::BroadcastLogger.new(Rails.logger)
-        broadcast_logger.formatter = Rails.logger.formatter
-        Rails.logger = broadcast_logger
+        unless Rails.logger.is_a?(ActiveSupport::BroadcastLogger)
+          broadcast_logger = ActiveSupport::BroadcastLogger.new(Rails.logger)
+          broadcast_logger.formatter = Rails.logger.formatter
+          Rails.logger = broadcast_logger
+        end
 
         unless config.consider_all_requests_local
           Rails.error.logger = Rails.logger

railties/test/application/configuration_test.rb

@@ -1893,6 +1893,26 @@ def index
       assert_equal Logger::DEBUG, Rails.logger.level
     end
 
+    test "config.logger when logger is already a Broadcast Logger" do
+      logger = ActiveSupport::BroadcastLogger.new
+
+      make_basic_app do |application|
+        application.config.logger = logger
+      end
+      assert_same(logger, Rails.logger)
+    end
+
+    test "config.logger when logger is not a Broadcast Logger" do
+      logger = Logger.new(STDOUT)
+
+      make_basic_app do |application|
+        application.config.logger = logger
+      end
+
+      assert_instance_of(ActiveSupport::BroadcastLogger, Rails.logger)
+      assert_includes(Rails.logger.broadcasts, logger)
+    end
+
     test "respond_to? accepts include_private" do
       make_basic_app