Association loading isn't to be affected by scoping consistently

Follow-up of 5c71000, #29834, and #30271.

Currently, preloading and eager loading are not to be affected by
scoping, with the exception of `unscoped`.

But non eager loaded association access is still affected by scoping.

Although this is a breaking change, the association loading will work
consistently whether preloaded / eager loaded or not.

Before:

```ruby
Post.where("1=0").scoping do
  Comment.find(1).post                   # => nil
  Comment.preload(:post).find(1).post    # => #<Post id: 1, ...>
  Comment.eager_load(:post).find(1).post # => #<Post id: 1, ...>
end
```

After:

```ruby
Post.where("1=0").scoping do
  Comment.find(1).post                   # => #<Post id: 1, ...>
  Comment.preload(:post).find(1).post    # => #<Post id: 1, ...>
  Comment.eager_load(:post).find(1).post # => #<Post id: 1, ...>
end
```

Fixes #34638.
Fixes #35398.

1 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 0bb63b97ae..cf22b850b9 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -225,7 +225,7 @@ module ActiveRecord
         # Can be overridden (i.e. in ThroughAssociation) to merge in other scopes (i.e. the
         # through association's scope)
         def target_scope
-          AssociationRelation.create(klass, self).merge!(klass.all)
+          AssociationRelation.create(klass, self).merge!(klass.scope_for_association)
         end
 
         def scope_for_create