Merge pull request rails#42590 from eileencodes/fix-disable-joins-with-sti-type

Fix disable joins with sti type

Author: eileencodes

activerecord/lib/active_record/associations/disable_joins_association_scope.rb

@@ -32,6 +32,12 @@ def last_scope_chain(reverse_chain, owner)
 
         def add_constraints(reflection, key, join_ids, owner, ordered)
           scope = reflection.build_scope(reflection.aliased_table).where(key => join_ids)
+
+          relation = reflection.klass.scope_for_association
+          scope.merge!(
+            relation.except(:select, :create_with, :includes, :preload, :eager_load, :joins, :left_outer_joins)
+          )
+
           scope = reflection.constraints.inject(scope) do |memo, scope_chain_item|
             item = eval_scope(reflection, scope_chain_item, owner)
             scope.unscope!(*item.unscope_values)

activerecord/lib/active_record/associations/has_one_through_association.rb

@@ -6,12 +6,6 @@ module Associations
     class HasOneThroughAssociation < HasOneAssociation #:nodoc:
       include ThroughAssociation
 
-      def find_target
-        return scope.first if disable_joins
-
-        super
-      end
-
       private
         def replace(record, save = true)
           create_through_record(record, save)

activerecord/lib/active_record/associations/singular_association.rb

@@ -38,7 +38,11 @@ def scope_for_create
         end
 
         def find_target
-          super.first
+          if disable_joins
+            scope.first
+          else
+            super.first
+          end
         end
 
         def replace(record)

activerecord/test/cases/associations/has_one_through_disable_joins_associations_test.rb

@@ -8,9 +8,11 @@
 require "models/developer"
 require "models/company"
 require "models/computer"
+require "models/club"
+require "models/membership"
 
 class HasOneThroughDisableJoinsAssociationsTest < ActiveRecord::TestCase
-  fixtures :members, :organizations, :projects, :developers, :companies
+  fixtures :members, :organizations, :projects, :developers, :companies, :clubs, :memberships
 
   def setup
     @member = members(:groucho)
@@ -61,4 +63,23 @@ def test_has_one_through_with_belongs_to_on_disable_joins
       assert_no_match(/INNER JOIN/, nj)
     end
   end
+
+  def test_disable_joins_through_with_enum_type
+    joins = capture_sql { @member.club }
+    no_joins = capture_sql { @member.club_without_joins }
+
+    assert_equal 1, joins.size
+    assert_equal 2, no_joins.size
+
+    assert_match(/INNER JOIN/, joins.first)
+    no_joins.each do |nj|
+      assert_no_match(/INNER JOIN/, nj)
+    end
+
+    if current_adapter?(:Mysql2Adapter)
+      assert_match(/`memberships`.`type`/, no_joins.first)
+    else
+      assert_match(/"memberships"."type"/, no_joins.first)
+    end
+  end
 end

activerecord/test/models/member.rb

@@ -5,6 +5,7 @@ class Member < ActiveRecord::Base
   has_one :selected_membership
   has_one :membership
   has_one :club, through: :current_membership
+  has_one :club_without_joins, through: :current_membership, source: :club, disable_joins: true
   has_one :selected_club, through: :selected_membership, source: :club
   has_one :favorite_club, -> { where "memberships.favorite = ?", true }, through: :membership, source: :club
   has_one :hairy_club, -> { where clubs: { name: "Moustache and Eyebrow Fancier Club" } }, through: :membership, source: :club