[myexperiment-hackers] Strange workflow error (caching?)

[Finn Bacall]

On my instance of myExperiment (created this morning using the latest 
version of the code). I can upload a workflow, view the workflow page 
without issue, but if I navigate away from the page, then return to it 
again (not using the back button in the browser) I get the following error:

"undefined method `contribution' for #<Workflow:0x7ff60c96da20> (full 
stack trace below)"

This error then continues to occur when I try and view the same, and 
certain other workflows* until I restart the server.

*The three test workflows that throw the error were all created from 
this t2flow file:
http://www.myexperiment.org/workflows/16

I have a fourth test workflow using this SCUFL file that doesn't 
trigger/react to the error:
http://www.myexperiment.org/workflows/72

This doesn't happen for Groups or Files.

Any ideas?

-Finn

Full stack trace:
/var/lib/gems/1.8/gems/activerecord-1.15.6/lib/active_record/base.rb:1863:in 
`method_missing'
/var/lib/gems/1.8/gems/activerecord-1.15.6/lib/active_record/associations/association_proxy.rb:123:in
 `send'
/var/lib/gems/1.8/gems/activerecord-1.15.6/lib/active_record/associations/association_proxy.rb:123:in
 `method_missing'
#{RAILS_ROOT}/app/controllers/workflows_controller.rb:236:in `show'
#{RAILS_ROOT}/app/controllers/workflows_controller.rb:233:in `map'
#{RAILS_ROOT}/app/controllers/workflows_controller.rb:233:in `show'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/base.rb:1101:in 
`send'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/base.rb:1101:in 
`perform_action_without_filters'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/filters.rb:696:in
 `call_filters'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/filters.rb:688:in
 `perform_action_without_benchmark'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/benchmarking.rb:66:in
 `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/benchmarking.rb:66:in
 `perform_action_without_rescue'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/rescue.rb:83:in 
`perform_action_without_caching'
/home/finn/workspace/myexperiment/vendor/plugins/query_cache/lib/query_cache.rb:133:in
 `perform_action'
/home/finn/workspace/myexperiment/vendor/plugins/query_cache/lib/query_cache.rb:106:in
 `cache'
/home/finn/workspace/myexperiment/vendor/plugins/query_cache/lib/query_cache.rb:132:in
 `perform_action'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/base.rb:435:in 
`send'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/base.rb:435:in 
`process_without_filters'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/filters.rb:684:in
 `process_without_session_management_support'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/session_management.rb:114:in
 `process'
/var/lib/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/base.rb:334:in 
`process'
/var/lib/gems/1.8/gems/rails-1.2.6/lib/dispatcher.rb:41:in `dispatch'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:488:in
 `load'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:488:in
 `load'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:342:in
 `new_constants_in'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:488:in
 `load'
/var/lib/gems/1.8/gems/rails-1.2.6/lib/commands/servers/mongrel.rb:60
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:495:in
 `require'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:342:in
 `new_constants_in'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:495:in
 `require'
/var/lib/gems/1.8/gems/rails-1.2.6/lib/commands/server.rb:39
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
script/server:3

--
Finn Bacall
School of Computer Science
University of Manchester