#4454 Adding a scope to ActiveRecord:Base throws undefined method exception - Ruby on Rails

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#4454 new

Adding a scope to ActiveRecord:Base throws undefined method exception

Reported by Saimon Moore | April 22nd, 2010 @ 09:57 AM

#works
class User < ActiveRecord::Base
  scope :random, lambda { |lt| where("created_at < ?", Time.now.utc).order('RAND()').limit(lt) }
end

#throws exception below
module ActiveRecord
  class Base
    scope :random, lambda { |lt| where("created_at < ?", Time.now.utc).order('RAND()').limit(lt) }
  end
end

ruby-1.9.1-p378 > User.random(1).first
NoMethodError: undefined method abstract_class?' for Object:Class<br/>

from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:1335:in `class_of_active_record_descendant'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:1000:in `base_class'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:759:in `reset_table_name'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:751:in `table_name'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:1032:in `arel_table'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:1027:in `unscoped'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/named_scope.rb:30:in `scoped'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:407:in `rescue in where'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/base.rb:405:in `where'
from /Users/saimon/Development/Projects/myapp_r3/config/initializers/active_record.rb:4:in `block in <class:Base>'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/named_scope.rb:95:in `call'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/named_scope.rb:95:in `block in scope'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/named_scope.rb:104:in `call'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/activerecord-3.0.0.beta3/lib/active_record/named_scope.rb:104:in `block (2 levels) in scope'
from (irb):1
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/railties-3.0.0.beta3/lib/rails/commands/console.rb:47:in `start'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/railties-3.0.0.beta3/lib/rails/commands/console.rb:8:in `start'
from /Users/saimon/.rvm/gems/ruby-1.9.1-p378@myapp/gems/railties-3.0.0.beta3/lib/rails/commands.rb:34:in `<top (required)>'
from script/rails:9:in `require'
from script/rails:9:in `<main>'ruby-1.9.1-p378 >

Comments and changes to this ticket

You flagged this item as spam.
Saimon Moore April 22nd, 2010 @ 09:57 AM
- Tag set to “activerecord rails3”
You flagged this item as spam.
Saimon Moore April 22nd, 2010 @ 09:58 AM
- Tag changed from “activerecord rails3” to “activerecord rails3, ruby-1.9.1”
Piotr Sarnacki December 17th, 2010 @ 10:57 AM
- Importance changed from “” to “Low”
I don't know if we should support that kind of scopes declaration. The more appropriate in that case would be to just use class method, as you're reopening base class:
```
def self.random(lt)
  where("created_at < ?", Time.now.utc).order('RAND()').limit(lt)
end
```
You flagged this item as spam.
Duke February 19th, 2011 @ 03:44 AM
I'm running across this as well. Every model here has a possible polymorphic relationship with Starlight.

module ActiveRecord
class Base
```
has_many :starlights, :as => :entity, :dependent => :destroy
def starlight
  Starlight.for(self)
end

scope :order_by_starlight, joins(:starlights).group('starlights.id').having('max(starlights.id)').order('starlights.value')
```
end end
I require order_by_starlight to be composable, so I can say, for instance, Entry.where(:user => current_user).order_by_starlight

This seems a good use case for adding scope to Activerecord::Base.
You flagged this item as spam.
Duke March 16th, 2011 @ 08:11 AM
Yes, I see with Arel a class method is composable.
You flagged this item as spam.
bingbing March 26th, 2011 @ 01:38 AM
omega watch