read_inheritable_attribute undefined in rails 3.2.8

Question

I get the following error message after upgrading to rails 3.2.8

NoMethodError (undefined method `read_inheritable_attribute' for AdminController:Class):

can someone explain me how to get around this error?

The whole trace

    NoMethodError (undefined method `read_inheritable_attribute' for AdminController:Class):
  vendor/plugins/ssl_requirement/lib/ssl_requirement.rb:45:in `ssl_allowed?'
  vendor/plugins/ssl_requirement/lib/ssl_requirement.rb:50:in `ensure_proper_protocol'
  activesupport (3.2.8) lib/active_support/callbacks.rb:440:in `_run__1166038054673275564__process_action__1642131706225346260__callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.8) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.2.8) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.2.8) lib/active_support/notifications.rb:123:in `block in instrument'
  activesupport (3.2.8) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (3.2.8) lib/active_support/notifications.rb:123:in `instrument'
  actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.2.8) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
  activerecord (3.2.8) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (3.2.8) lib/abstract_controller/base.rb:121:in `process'
  actionpack (3.2.8) lib/abstract_controller/rendering.rb:45:in `process'
  actionpack (3.2.8) lib/action_controller/metal.rb:203:in `dispatch'
  actionpack (3.2.8) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.2.8) lib/action_controller/metal.rb:246:in `block in action'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `call'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:36:in `call'
  journey (1.0.4) lib/journey/router.rb:68:in `block in call'
  journey (1.0.4) lib/journey/router.rb:56:in `each'
  journey (1.0.4) lib/journey/router.rb:56:in `call'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:600:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  rack (1.4.1) lib/rack/etag.rb:23:in `call'
  rack (1.4.1) lib/rack/conditionalget.rb:25:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/head.rb:14:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/flash.rb:242:in `call'
  rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'
  rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/cookies.rb:339:in `call'
  activerecord (3.2.8) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_pool.rb:473:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `_run__2439266315320850734__call__4114460638497368676__callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  rack (1.4.1) lib/rack/sendfile.rb:102:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.8) lib/rails/rack/logger.rb:26:in `call_app'
  railties (3.2.8) lib/rails/rack/logger.rb:16:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.1) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.8) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.1) lib/rack/lock.rb:15:in `call'
  rack-cache (1.2) lib/rack/cache/context.rb:136:in `forward'
  rack-cache (1.2) lib/rack/cache/context.rb:245:in `fetch'
  rack-cache (1.2) lib/rack/cache/context.rb:185:in `lookup'
  rack-cache (1.2) lib/rack/cache/context.rb:66:in `call!'
  rack-cache (1.2) lib/rack/cache/context.rb:51:in `call'
  railties (3.2.8) lib/rails/engine.rb:479:in `call'
  railties (3.2.8) lib/rails/application.rb:223:in `call'
  railties (3.2.8) lib/rails/railtie/configurable.rb:30:in `method_missing'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/rack/request_handler.rb:96:in `process_request'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_request_handler.rb:513:in `accept_and_process_next_request'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_request_handler.rb:274:in `main_loop'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/rack/application_spawner.rb:206:in `start_request_handler'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/rack/application_spawner.rb:171:in `block in handle_spawn_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/utils.rb:479:in `safe_fork'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/rack/application_spawner.rb:166:in `handle_spawn_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server.rb:180:in `start'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/rack/application_spawner.rb:129:in `start'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/spawn_manager.rb:253:in `block (2 levels) in spawn_rack_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server_collection.rb:132:in `lookup_or_add'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/spawn_manager.rb:246:in `block in spawn_rack_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server_collection.rb:82:in `block in synchronize'
  <internal:prelude>:10:in `synchronize'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server_collection.rb:79:in `synchronize'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/spawn_manager.rb:244:in `spawn_rack_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/spawn_manager.rb:137:in `spawn_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/spawn_manager.rb:275:in `handle_spawn_application'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
  /usr/lib64/ruby/site_ruby/1.9.1/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
  /usr/share/phusion-passenger/helper-scripts/passenger-spawn-server:99:in `<main>'

Answer 1

read_inheritable_attribute has been deprecated, you may want to check out class_attribute instead