Eager loading uniq habtm association is broken

+1 verified and reproduced on master and 2-3-stable. i've attached a failing test.

the failing test if for master.

-1 changing the developers.yml somehow introduced failures in other tests.

I rewrote it using dev_3 instead. I've attached the edited failing test.

Also, this is my take on patching the issue. I thought of adding something like (-190,6 +190,7):

+  associated_records.uniq! if options[:uniq]
   set_association_collection_records(id_to_record_map, reflection.name, associated_records, 'the_parent_record_id')

to #preload_has_and_belongs_to_many_association, but I think this is a more general issue. Instead, it seems that when #load_target is called by #count_records, the target is already loaded. I've attached a patch. (Applies to master and 2-3-stable).

I'm also unsure if this is the optimal way (alternative, options[:select] = 'DISTINCT *').

I've attached reworked patches for master and 2-3-stable. The implementation is slightly different than previously specified. Instead of

associated_records.uniq! if options[:uniq]

I've gone the DISTINCT method, because that seems to be the behavior for has_many :through with :uniq => true and custom :select (see construct_select in through_association_scope.rb:48).

Sure, here are the patches created from rails root.

not sure why but I am still getting the error while applying your patch

(master)$ git am < patch.txt 
Applying: Fix a bug where eager loading of a :uniq => true has_and_belongs_to_many returns duplicate entries
error: activerecord/lib/active_record/association_preload.rb: does not match index
error: activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb: does not match index
Patch failed at 0001 Fix a bug where eager loading of a :uniq => true has_and_belongs_to_many returns duplicate entries
When you have resolved this problem run "git am --resolved".
If you would prefer to skip this patch, instead run "git am --skip".
To restore the original branch and stop patching run "git am --abort".

@Neeraj, I'm not sure why either. I've applied the patch multiple times today at different commits, most recently on [387036609268c4cf68401a1333715f2ee4aecffc], and it's worked.

It looks like you've had a few patches accepted recently, did you reset the branch and pull from master before you applied my patch? Or do you have any unstaged changes on association_preload.rb or has_and_belongs_to_many_associations_test.rb?

I checked out brand new rails app before applying the patch. Well someone else will verify your patch.

Okay, that's pretty weird. Well thanks anyway.