StateMachine::InvalidTransition in checkout#paypal_confirm

[patrickmcelwee]

I am on the edge of Spree's 1-0-stable branch and a customer just got this error when returning from PayPal:

A StateMachine::InvalidTransition occurred in checkout#paypal_confirm:

  Cannot transition state via :next from "payment" (Reason(s): Transition halted)
  state_machine (1.1.1) lib/state_machine/event.rb:241:in `block in add_actions'

The backtrace is:

  state_machine (1.1.1) lib/state_machine/event.rb:241:in `block in add_actions' 
  state_machine (1.1.1) lib/state_machine/machine.rb:753:in `call'
  state_machine (1.1.1) lib/state_machine/machine.rb:753:in `block (2 levels) in define_helper'
  /data/spree/shared/bundle/ruby/1.9.1/bundler/gems/spree_paypal_express-77840ade5a48/app/controllers/spree/checkout_controller_decorator.rb:150:in `paypal_finish'
  /data/spree/shared/bundle/ruby/1.9.1/bundler/gems/spree_paypal_express-77840ade5a48/app/controllers/spree/checkout_controller_decorator.rb:98:in `paypal_confirm'
  actionpack (3.1.6) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
  actionpack (3.1.6) lib/abstract_controller/base.rb:167:in `process_action'
  actionpack (3.1.6) lib/action_controller/metal/rendering.rb:10:in `process_action'
  actionpack (3.1.6) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
  activesupport (3.1.6) lib/active_support/callbacks.rb:497:in `_run__974073426__process_action__998365959__callbacks'
  activesupport (3.1.6) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
  activesupport (3.1.6) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.1.6) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.1.6) lib/action_controller/metal/rescue.rb:17:in `process_action'
  actionpack (3.1.6) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.1.6) lib/active_support/notifications.rb:53:in `block in instrument'
  activesupport (3.1.6) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
  activesupport (3.1.6) lib/active_support/notifications.rb:53:in `instrument'
  actionpack (3.1.6) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.1.6) lib/action_controller/metal/params_wrapper.rb:201:in `process_action'
  activerecord (3.1.6) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  newrelic_rpm (3.3.2) lib/new_relic/agent/instrumentation/rails3/action_controller.rb:34:in `block in process_action'
  newrelic_rpm (3.3.2) lib/new_relic/agent/instrumentation/controller_instrumentation.rb:255:in `block in perform_action_with_newrelic_trace'
  newrelic_rpm (3.3.2) lib/new_relic/agent/method_tracer.rb:242:in `trace_execution_scoped'
  newrelic_rpm (3.3.2) lib/new_relic/agent/instrumentation/controller_instrumentation.rb:250:in `perform_action_with_newrelic_trace'
  newrelic_rpm (3.3.2) lib/new_relic/agent/instrumentation/rails3/action_controller.rb:33:in `process_action'
  actionpack (3.1.6) lib/abstract_controller/base.rb:121:in `process'
  actionpack (3.1.6) lib/abstract_controller/rendering.rb:45:in `process'
  actionpack (3.1.6) lib/action_controller/metal.rb:193:in `dispatch'
  actionpack (3.1.6) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.1.6) lib/action_controller/metal.rb:236:in `block in action'
  actionpack (3.1.6) lib/action_dispatch/routing/route_set.rb:71:in `call'
  actionpack (3.1.6) lib/action_dispatch/routing/route_set.rb:71:in `dispatch'
  actionpack (3.1.6) lib/action_dispatch/routing/route_set.rb:35:in `call'
  rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
  rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
  rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `optimized_each'
  rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
  rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
  actionpack (3.1.6) lib/action_dispatch/routing/route_set.rb:538:in `call'
  /data/spree/shared/bundle/ruby/1.9.1/bundler/gems/spree-0760b901247f/core/lib/spree/core/middleware/redirect_legacy_product_url.rb:13:in `call'
  /data/spree/shared/bundle/ruby/1.9.1/bundler/gems/spree-0760b901247f/core/lib/spree/core/middleware/seo_assist.rb:27:in `call'
  railties (3.1.6) lib/rails/engine.rb:456:in `call'
  railties (3.1.6) lib/rails/railtie/configurable.rb:30:in `method_missing'
  rack-mount (0.8.3) lib/rack/mount/prefix.rb:26:in `call'
  rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
  rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
  rack-mount (0.8.3) lib/rack/mount/code_generation.rb:68:in `optimized_each'
  rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
  rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
  actionpack (3.1.6) lib/action_dispatch/routing/route_set.rb:538:in `call'
  newrelic_rpm (3.3.2) lib/new_relic/rack/browser_monitoring.rb:23:in `call'
  exception_notification (2.6.1) lib/exception_notifier.rb:34:in `call'
  warden (1.0.6) lib/warden/manager.rb:35:in `block in call'
  warden (1.0.6) lib/warden/manager.rb:34:in `catch'
  warden (1.0.6) lib/warden/manager.rb:34:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  rack (1.3.6) lib/rack/etag.rb:23:in `call'
  rack (1.3.6) lib/rack/conditionalget.rb:25:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/head.rb:14:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/flash.rb:243:in `call'
  rack (1.3.6) lib/rack/session/abstract/id.rb:195:in `context'
  rack (1.3.6) lib/rack/session/abstract/id.rb:190:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/cookies.rb:331:in `call'
  activerecord (3.1.6) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.1.6) lib/active_record/connection_adapters/abstract/connection_pool.rb:477:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
  activesupport (3.1.6) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
  activesupport (3.1.6) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.1.6) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
  rack (1.3.6) lib/rack/sendfile.rb:101:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
  actionpack (3.1.6) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
  railties (3.1.6) lib/rails/rack/logger.rb:13:in `call'
  rack (1.3.6) lib/rack/methodoverride.rb:24:in `call'
  rack (1.3.6) lib/rack/runtime.rb:17:in `call'
  activesupport (3.1.6) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.3.6) 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 (3.1.6) lib/rails/engine.rb:456:in `call'
  railties (3.1.6) lib/rails/application.rb:143:in `call'
  railties (3.1.6) lib/rails/railtie/configurable.rb:30:in `method_missing'
  unicorn (4.2.0) lib/unicorn/http_server.rb:530:in `process_client'
  unicorn (4.2.0) lib/unicorn/http_server.rb:604:in `worker_loop'
  newrelic_rpm (3.3.2) lib/new_relic/agent/instrumentation/unicorn_instrumentation.rb:17:in `call'
  newrelic_rpm (3.3.2) lib/new_relic/agent/instrumentation/unicorn_instrumentation.rb:17:in `block (4 levels) in <top (required)>'
  unicorn (4.2.0) lib/unicorn/http_server.rb:487:in `spawn_missing_workers'
  unicorn (4.2.0) lib/unicorn/http_server.rb:498:in `maintain_worker_count'
  unicorn (4.2.0) lib/unicorn/http_server.rb:272:in `join'
  unicorn (4.2.0) bin/unicorn_rails:209:in `<top (required)>'
  /data/spree/shared/bundle/ruby/1.9.1/bin/unicorn_rails:19:in `load'
  /data/spree/shared/bundle/ruby/1.9.1/bin/unicorn_rails:19:in `<main>'

[radar]

Please provide steps to reproduce this issue

[patrickmcelwee]

I can confirm that this was caused by bumping my version of Spree 1.0 from 33035d8bff158a2a18b43806a27accf590d23f16 (where a PayPal checkout works) to 0760b901247f0bf8839a69a620a0d31d8afc9aef

In order to reproduce, I had to add attr_accessible to the 1-0-stable branch. I have a pull request to fix that separate issue: #69

Here are the steps:

1. Setup Spree store using Spree ref: 0760b901247f0bf8839a69a620a0d31d8afc9aef
2. Add gem spree_paypal_express, branch: 1-0-stable
3. You will need a PayPal Developer Account to create a test Business Account.
4. In Development Server, as admin on /admin/payment_methods, create a Spree::BillingIntegration::PaypalExpress with the following options: Environment => 'Development', Display => 'Both', Active => 'Yes', Fill in Login, Password and Signature with test developer account information. Server => 'test', Test Mode => checked; [I also have Review unchecked and "No Shipping" Checked]. Click update.
5. Create an order with one product.
6. Proceed through checkout to payment and choose PayPal.
7. Go to PayPal and fill in information. Confirm payment.
8. The above error is raised.

Thanks for taking a look radar!

[radar]

Fixed with #69.