[PATCH] raise_on_type_mismatch on has_many :through

Does this only happen in development mode?

When rails reloads itself in development mode then indeed the object_id for the reloaded classes changes, but in this case it would appear that User gets reloaded after the tag thingy gets a reference to the "old" User.

Does this error dissapear if in the beginning of the action that causes the error you reference the User class?

Could you try printing the User.object_id out at the beginning of the action and at the end of the action, does it change then?

I have the same problem. All works in production environment, but development scaring me. I think it's very important ticket, cuze bug like this makes impossible rails development.

Oh yeahhh I have a solution: If your plugins have references to Models,etc (those classes reloadable by each request in development mode) add folowing lines of code to environment.rb

# Array of plugins with Application model dependencies. reloadable_plugins = ['acts_as_taggable', 'acts_as_rateable', 'acts_as_commentable']

# Force these plugins to reload, avoiding stale object references. reloadable_plugins.each do |plugin_name|

reloadable_path = RAILS_ROOT + "/vendor/plugins/#{plugin_name}/lib" Dependencies.load_once_paths.delete(reloadable_path)

end

It will reload specified plugins. Good luck.

If you are using dev_mode_performance_fixes, this bug may also apply to you. We disabled (deleted) this plugin, and stopped receiving these errors.

Another data point: This error also occurs with a belongs_to relationship (again, in development mode):

  class Foo << AR::B; belongs_to :bar; end

I'm loading the Foo class in config/environment.rb (to set some configuration). As a consequence, it is only loaded that one time. The Bar class is of course loaded on every request. The result is again that Foo has stale data in its AssociationProxy.

config.to_prepare { require_dependency 'foo' }

bitsweat...could you provide a bit more details if it's truly resolved? I'm not sure I completely understand "config.to_prepare { require_dependency 'foo' }" in the context of this ticket.

Thanks!

It ensures the models you're working with are reloaded on each request.

See also all the reports at

http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/d2adc451ff0236c2/b95a3bc9cb97f988?#b95a3bc9cb97f988

The method raise_on_type_mismatch in association_proxy.rb should only check for matching type, not for matching object as it does now.

Michael Bryzek gave a solution that works.

Attached is the patch.

+1, this one line patch fixed the annoying ActiveRecord::AssociationTypeMismatch exception with the frustrating "Model expected, got Model" issue in development for me even in r8820

+1 happens to me on recent Edge Rails

+1 after an morning trying to understand my "Language expected, got Language" problem, I hope to see the patch applied soon

Needs a test demonstrating that it's fixed.

I get this if I have one class that 'overrides' another. I.e. class Image # in a plugin end class Image # in app/models -- meant to 'override' the use of the plugin image. end

The error message seems very misleading Image expected, got Image. Ugh. A better way would be Image [id XXX] expected, got Image [id YYY]

another way to fix it is: module ActiveRecord

module Associations

class AssociationProxy #:nodoc:

private

def raise_on_type_mismatch(record)

unless record.class == @reflection.klass or record.class.ancestors.include?(@reflection.klass)

raise ActiveRecord::AssociationTypeMismatch, "#{@reflection.class_name} ID #{@reflection.id} expected, got #{record.class} ID #{record.id}"

end

end

end

end

end

Not sure which one would be faster or what not, esp. with 1.9

+1, I get this on edge as well

@rogerdpack you're suggestion doesn't work unfortunately, try it out and several tests will fail.

Attached new patch. Now including test to prove this thing.

Further development on this ticket has moved to:

http://rails.lighthouseapp.com/projects/8994/tickets/229-raise_on_type_mismatch-expected-user-got-user#ticket-229-1