Eager fetching a HABTM fails when the HABTM uses the "include" option
Reported by Mark Roghelia | June 2nd, 2008 @ 10:53 PM
This ticket assumes that the fix for eager fetching HABTMs that is detailed in ticket #304 has been applied.
Eager fetching a "has_and_belongs_to_many" association as part of a find generates as error when that association is defined to include another HABTM with the "include" option.
Consider the following example. A UserProfile class has a "has_and_belongs_to_many" association with UserRole. UserRole in turn has a HABTM with Permission. In UserProfile, the "user_roles" association is defined to include the permissions, as follows:
class UserProfile < ActiveRecord::Base
has_and_belongs_to_many :user_roles, :include => :permissions
end
If I call UserProfile.find(1, :include => :user_roles), I get the following error:
/Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/runner.rb:47: /Users/mark/src/msd/lib/preload_association.rb:45:in `add_preloaded_records_to_collection': You have a nil object when you didn't expect it! (NoMethodError)
You might have expected an instance of Array.
The error occurred while evaluating nil.each from /Users/mark/src/msd/lib/preload_association.rb:63:in `set_association_collection_records'
from /Users/mark/src/msd/lib/preload_association.rb:61:in `each'
from /Users/mark/src/msd/lib/preload_association.rb:61:in `set_association_collection_records'
from /Users/mark/src/msd/lib/preload_association.rb:109:in `preload_has_and_belongs_to_many_association'
from /Users/mark/src/msd/lib/preload_association.rb:40:in `send'
from /Users/mark/src/msd/lib/preload_association.rb:40:in `preload_one_association'
from /Users/mark/src/msd/lib/preload_association.rb:38:in `each'
from /Users/mark/src/msd/lib/preload_association.rb:38:in `preload_one_association'
... 11 levels...
from /Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/runner.rb:47
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `require'
from ./script/runner:3
This seems to result from the "_parent_id" column not being included in the query. If I leave ":include => :permission" out of the definition of "user_roles", this works (assuming the patch from ticket #304 has been applied).
Comments and changes to this ticket
-
James Kebinger June 5th, 2008 @ 10:47 PM
I just hit this problem myself on 2.1 w/ postgres.
I can concur the _parent_id is left out, as it looks like the :select option (which contains the needed _parent_id) is completely ignored in
ActiveRecord::Associations:construct_finder_sql_with_included_associations
-
James Kebinger October 23rd, 2008 @ 04:23 PM
I suspect this problem is linked with #77 http://rails.lighthouseapp.com/p...
-
Pratik July 23rd, 2008 @ 02:12 PM
- → Tag changed from “” to “2.1 activerecord bug eager_loading”
- → State changed from “new” to “duplicate”
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