#2953 without_exclusive_scope and default_scope issues - Ruby on Rails

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#2953 ✓stale

without_exclusive_scope and default_scope issues

Reported by Conrad Taylor | July 25th, 2009 @ 05:55 AM | in 3.x

I'm seeing the following issues with both without_exclusive_scope and default_scope in Rails 2.3.3. For example, given the following:


class Message < ActiveRecord::Base
  
  default_scope :conditions => { :ignored => false }, :order => "rating DESC"
  named_scope :positive, :conditions => { :rating => 'positive' }
  named_scope :neutral, :conditions =>  { :rating => 'neutral' }
  named_scope :negative, :conditions => { :rating => 'negative' }
  named_scope :ignored, :conditions =>  { :ignored => true }
  
end

In the console,


> Message.ignored

=>  SELECT * FROM "messages" WHERE ("messages"."ignored" = 'f') ORDER BY rating DESC

Next, when trying to use the 'with_exclusive_scope method, the following message is generated:


>> Message.with_exclusive_scope { find( :all ) }
NoMethodError: protected method `with_exclusive_scope' called for #<Class:0x793538>
    from /opt/local/lib/ruby/gems/1.9.1/gems/activerecord-2.3.3/lib/active_record/base.rb:1959:in `method_missing'
    from (irb):9
    from /opt/local/bin/irb:12:in `<main>'

message.zip 104.5 KB

Comments and changes to this ticket

Matt Jones July 26th, 2009 @ 12:47 AM
As to the second half, with_exclusive_scope was made protected along with with_scope a while back. You're probably better off wrapping the with_exclusive_scope call inside a model method.

There's definitely something weird going on with the first case - if you create a second model class, identical except for the default scope and try:
```
MessageWithoutDefault.scoped(:conditions => { :ignored => false }).ignored
```
...then you get the correct behavior.
I'm investigating and will post an update (hopefully) soon.
Matt Jones July 26th, 2009 @ 03:38 AM
On further investigation, here's the situation:

Chaining two named_scopes does something (somewhat) unexpected - they nest in the reverse order.

In other words, this:
```
MessageWithoutDefault.scoped(:conditions => { :ignored => false }).ignored.all
```
executes as:
```
MessageWithoutDefault.with_scope([PARAMS FOR IGNORED]) do
  MessageWithoutDefault.with_scope([PARAMS FOR IGNORED => FALSE]) do
```
```
MessageWithoutDefault.find(:all)
```
```
  end
end
```
would if with_scope was public. The outer with_scope parameters take precedence. This works fine normally, but adding a default_scope is equivalent to this:
```
MessageWithoutDefault.with_scope([PARAMS FOR DEFAULT SCOPE]) do # NOTE: not actually executed - default scope is inserted differently
  MessageWithoutDefault.with_scope([PARAMS FOR IGNORED]) do
```
```
MessageWithoutDefault.with_scope([PARAMS FOR IGNORED =&gt; FALSE]) do
  MessageWithoutDefault.find(:all)
end
```
```
  end
end
```
which produces the (observed) incorrect results.
There's a bigger issue here, though; with_scope tends to flatten Hash conditions to strings, making it hard to override :conditions in default_scope. For instance, doing this:
```
Message.ignored.scoped(:conditions => ['rating LIKE ?', 'p%'])
```
=> SELECT * FROM "messages" WHERE ((("messages"."ignored" = 'f') AND (rating LIKE 'p%')) AND ("messages"."ignored" = 't')) ORDER BY rating DESC
which will never return any records. The issue here is that the first part of the query (before the last AND) is generated as a string by merge_conditions, so there's no chance to override it.
Maybe some of the ActiveRelation stuff going on in the GSoC will help with this?

Chuck Hoffman November 24th, 2009 @ 05:24 PM

I seem to be experiencing this same issue. Here's a description I posted earlier at https://gist.github.com/ea8322b9c7383835101c

class MyModel < ActiveRecord::Base

  belongs_to :parent_model

  # ...

  default_scope :conditions => { :is_hidden => false }
  named_scope :primary, :conditions => { :is_primary => true },
    :order => "position"
  named_scope :secondary, :conditions => { :is_primary => false },
    :order => "position"
  

p = ParentModel.first
p.my_models            #<-- works fine
p.my_models.primary    #<-- works fine
p.my_models.secondary  #<-- works fine

# what I need is a finder method/scope to find on the condition { :is_hidden => true }
# preferably one that also works through the belongs_to :parent association.

# here are some things I've tried:

  named_scope :hidden, :conditions => { :is_hidden => true }
# p.my_models.hidden seems to end up acting identically to p.my_models.secondary in this
# case.  Might also be the case if called on the class as MyModel.hidden
# (see https://rails.lighthouseapp.com/projects/8994/tickets/2953-without_exclusive_scope-and-default_scope-issues)

  def self.find_with_hidden(*args)
    self.with_exclusive_scope { find(*args) }
  end
# here I'm adapting the find_with_destroyed method shown on
# http://blog.semanticart.com/using_default_scope_to_recreate_acts_as_paranoid/
# unfortunately, it won't work correctly through an association: calling
# p.my_models.find_with_hidden(:all) returns all MyModels, not just those that
# belong to p -- in other words, with_exclusive_scope is TOO exclusive because
# it loses the association scope.

# But if I try passing the above more conditions to get the results I want, I get errors:

  MyModel.find_with_hidden(:conditions => { :parent_model_id => 1 })
# gets this error:
# ActiveRecord::RecordNotFound: Couldn't find MyModel without an ID
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:1567:in `find_from_ids'
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:616:in `find'
#   from /home/chuck/projects/diyseo/app/models/page_keyword.rb:34:in `find_with_business_name'
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2143:in `with_scope'
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2151:in `with_exclusive_scope'
#   from /home/chuck/projects/diyseo/app/models/page_keyword.rb:34:in `find_with_business_name'

  MyModel.find_with_hidden(:conditions => { :is_hidden => true })
# ActiveRecord::RecordNotFound: Couldn't find MyModel without an ID
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:1567:in `find_from_ids'
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:616:in `find'
#   from /home/chuck/projects/diyseo/app/models/page_keyword.rb:34:in `find_with_business_name'
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2143:in `with_scope'
#   from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2151:in `with_exclusive_scope'
#   from /home/chuck/projects/diyseo/app/models/page_keyword.rb:34:in `find_with_business_name'

# Likewise if I try calling the above from an instance method on MyModel like this:
  def self.hidden_for(parent)
    MyModel.find_with_hidden(:conditions => {
                               :parent_model_id => parent.id,
                               :is_hidden       => true
                             })
  end
# calling:
  p.my_models.hidden_for(p)
# or:
  MyModel.hidden_for(p)
# both result in the "Couldn't find MyModel without an ID" error above

Jeremy Kemper May 4th, 2010 @ 06:48 PM
- Milestone changed from “2.x” to “3.x”
[bulk edit]
Rohit Arondekar October 9th, 2010 @ 04:01 AM
- State changed from “new” to “stale”
- Importance changed from “” to “”
Marking ticket as stale. If this is still an issue please leave a comment with suggested changes, creating a patch with tests, rebasing an existing patch or just confirming the issue on a latest release or master/branches.
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