8 files changed, 31 insertions, 7 deletions
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
index c01138c059..3525fa2ab8 100644
--- a/activerecord/test/cases/associations/belongs_to_associations_test.rb
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -448,8 +448,13 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_with_select
-    assert_equal 1, Company.find(2).firm_with_select.attributes.size
-    assert_equal 1, Company.all.merge!(includes: :firm_with_select).find(2).firm_with_select.attributes.size
+    assert_equal 1, Post.find(2).author_with_select.attributes.size
+    assert_equal 1, Post.includes(:author_with_select).find(2).author_with_select.attributes.size
+  end
+
+  def test_custom_attribute_with_select
+    assert_equal 2, Company.find(2).firm_with_select.attributes.size
+    assert_equal 2, Company.includes(:firm_with_select).find(2).firm_with_select.attributes.size
   end
 
   def test_belongs_to_without_counter_cache_option
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 363593ca19..1b8f748bad 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1226,14 +1226,15 @@ class BasicsTest < ActiveRecord::TestCase
   end
 
   def test_attribute_names
-    assert_equal ["id", "type", "firm_id", "firm_name", "name", "client_of", "rating", "account_id", "description"],
-                 Company.attribute_names
+    expected = ["id", "type", "firm_id", "firm_name", "name", "client_of", "rating", "account_id", "description", "metadata"]
+    assert_equal expected, Company.attribute_names
   end
 
   def test_has_attribute
     assert Company.has_attribute?("id")
     assert Company.has_attribute?("type")
     assert Company.has_attribute?("name")
+    assert Company.has_attribute?("metadata")
     assert_not Company.has_attribute?("lastname")
     assert_not Company.has_attribute?("age")
   end
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 850bc49676..b001667ac9 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -690,8 +690,9 @@ class CalculationsTest < ActiveRecord::TestCase
   end
 
   def test_pluck_not_auto_table_name_prefix_if_column_joined
-    Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
-    assert_equal [7], Company.joins(:contracts).pluck(:developer_id)
+    company = Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)])
+    metadata = company.contracts.first.metadata
+    assert_equal [metadata], Company.joins(:contracts).pluck(:metadata)
   end
 
   def test_pluck_with_selection_clause
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 0ab0459c38..857d743605 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -14,6 +14,7 @@ require "models/person"
 require "models/computer"
 require "models/reply"
 require "models/company"
+require "models/contract"
 require "models/bird"
 require "models/car"
 require "models/engine"
@@ -1815,6 +1816,12 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal [1, 1, 1], posts.map(&:author_address_id)
   end
 
+  test "joins with select custom attribute" do
+    contract = Company.create!(name: "test").contracts.create!
+    company = Company.joins(:contracts).select(:id, :metadata).find(contract.company_id)
+    assert_equal contract.metadata, company.metadata
+  end
+
   test "delegations do not leak to other classes" do
     Topic.all.by_lifo
     assert Topic.all.class.method_defined?(:by_lifo)
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index 838f515aad..a0f48d23f1 100644
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -13,6 +13,8 @@ class Company < AbstractCompany
   has_many :contracts
   has_many :developers, through: :contracts
 
+  attribute :metadata, :json
+
   scope :of_first_firm, lambda {
     joins(account: :firm).
     where("firms.id" => 1)
diff --git a/activerecord/test/models/contract.rb b/activerecord/test/models/contract.rb
index 3f663375c4..89719775c4 100644
--- a/activerecord/test/models/contract.rb
+++ b/activerecord/test/models/contract.rb
@@ -5,7 +5,9 @@ class Contract < ActiveRecord::Base
   belongs_to :developer, primary_key: :id
   belongs_to :firm, foreign_key: "company_id"
 
-  before_save :hi
+  attribute :metadata, :json
+
+  before_save :hi, :update_metadata
   after_save :bye
 
   attr_accessor :hi_count, :bye_count
@@ -19,6 +21,10 @@ class Contract < ActiveRecord::Base
     @bye_count ||= 0
     @bye_count += 1
   end
+
+  def update_metadata
+    self.metadata = { company_id: company_id, developer_id: developer_id }
+  end
 end
 
 class NewContract < Contract
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index e32cc59399..65d1fce66d 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -31,6 +31,7 @@ class Post < ActiveRecord::Base
 
   belongs_to :author_with_posts, -> { includes(:posts) }, class_name: "Author", foreign_key: :author_id
   belongs_to :author_with_address, -> { includes(:author_address) }, class_name: "Author", foreign_key: :author_id
+  belongs_to :author_with_select, -> { select(:id) }, class_name: "Author", foreign_key: :author_id
 
   def first_comment
     super.body
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 86d5a67a13..349b8afc48 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -247,6 +247,7 @@ ActiveRecord::Schema.define do
   create_table :contracts, force: true do |t|
     t.references :developer, index: false
     t.references :company, index: false
+    t.string :metadata
   end
 
   create_table :customers, force: true do |t|