Setup on_encrypted_attribute_declared hook only once

activerecord/lib/active_record/encryption/configurable.rb

@@ -50,7 +50,7 @@ module ActiveRecord
           end
         end
 
-        def install_auto_filtered_parameters(application) # :nodoc:
+        def install_auto_filtered_parameters_hook(application) # :nodoc:
           ActiveRecord::Encryption.on_encrypted_attribute_declared do |klass, encrypted_attribute_name|
             application.config.filter_parameters << encrypted_attribute_name unless ActiveRecord::Encryption.config.excluded_from_filter_parameters.include?(name)
           end

activerecord/lib/active_record/railtie.rb

@@ -360,9 +360,9 @@ To keep using the current cache store, you can turn off cache versioning entirel
       end
 
       # Filtered params
-      ActiveSupport.on_load(:action_controller) do
+      ActiveSupport.on_load(:action_controller, run_once: true) do
         if ActiveRecord::Encryption.config.add_to_filter_parameters
-          ActiveRecord::Encryption.install_auto_filtered_parameters(app)
+          ActiveRecord::Encryption.install_auto_filtered_parameters_hook(app)
         end
       end
     end

activerecord/test/cases/encryption/configurable_test.rb

@@ -43,7 +43,7 @@ class ActiveRecord::Encryption::ConfigurableTest < ActiveRecord::EncryptionTestC
 
   test "install autofiltered params" do
     application = OpenStruct.new(config: OpenStruct.new(filter_parameters: []))
-    ActiveRecord::Encryption.install_auto_filtered_parameters(application)
+    ActiveRecord::Encryption.install_auto_filtered_parameters_hook(application)
 
     Class.new(Pirate) do
       self.table_name = "pirates"