Revert "Merge pull request rails#47864 from zenspider/zenspider/ar_core_hash"

This reverts commit 2815cb9, reversing
changes made to 11a5e37.

The change broke application code and if we are going to make this
change we will need to deprecate the prior behavior. See rails#47864 for more
details.

Author: eileencodes

activerecord/lib/active_record/core.rb

@@ -551,12 +551,10 @@ def encode_with(coder)
     # Note also that destroying a record preserves its ID in the model instance, so deleted
     # models are still comparable.
     def ==(comparison_object)
-      return super if new_record?
       super ||
         comparison_object.instance_of?(self.class) &&
         primary_key_values_present? &&
-        comparison_object.id == id &&
-        !comparison_object.new_record?
+        comparison_object.id == id
     end
     alias :eql? :==
 
@@ -565,8 +563,8 @@ def ==(comparison_object)
     def hash
       id = self.id
 
-      if primary_key_values_present? && !new_record?
-        [self.class, id].hash
+      if primary_key_values_present?
+        self.class.hash ^ id.hash
       else
         super
       end

activerecord/test/cases/attribute_methods_test.rb

@@ -811,10 +811,8 @@ def topic.approved; false; end
 
   test "YAML dumping a record with time zone-aware attribute" do
     in_time_zone "Pacific Time (US & Canada)" do
-      Topic.where(id: 1).delete_all
       record = Topic.new(id: 1)
       record.written_on = "Jan 01 00:00:00 2014"
-      record.save!
       payload = YAML.dump(record)
       assert_equal record, YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(payload) : YAML.load(payload)
     end

activerecord/test/cases/base_test.rb

@@ -625,6 +625,12 @@ def test_equality_of_destroyed_records
     assert_equal topic_2, topic_1
   end
 
+  def test_equality_with_blank_ids
+    one = Subscriber.new(id: "")
+    two = Subscriber.new(id: "")
+    assert_equal one, two
+  end
+
   def test_equality_of_relation_and_collection_proxy
     car = Car.create!
     car.bulbs.build

activerecord/test/cases/core_test.rb

@@ -7,28 +7,9 @@
 require "models/cpk"
 
 class NonExistentTable < ActiveRecord::Base; end
-class PkWithDefault < ActiveRecord::Base; end
 
 class CoreTest < ActiveRecord::TestCase
-  fixtures :topics, :cpk_books
-
-  def test_eql_on_default_pk
-    saved_record = PkWithDefault.new
-    saved_record.save!
-    assert_equal 123, saved_record.id
-
-    record = PkWithDefault.new
-    assert_equal 123, record.id
-
-    record2 = PkWithDefault.new
-    assert_equal 123, record2.id
-
-    assert     record.eql?(record),       "record should eql? itself"
-    assert_not record.eql?(saved_record), "new record should not eql? saved"
-    assert_not saved_record.eql?(record), "saved record should not eql? new"
-    assert_not record.eql?(record2),      "new record should not eql? new record"
-    assert_not record2.eql?(record),      "new record should not eql? new record"
-  end
+  fixtures :topics
 
   def test_inspect_class
     assert_equal "ActiveRecord::Base", ActiveRecord::Base.inspect
@@ -174,12 +155,12 @@ def test_find_by_cache_does_not_duplicate_entries
 
   def test_composite_pk_models_added_to_a_set
     library = Set.new
-    # new record with primary key present
+    # with primary key present
     library << Cpk::Book.new(author_id: 1, number: 2)
 
     # duplicate
-    library << cpk_books(:cpk_great_author_first_book)
-    library << cpk_books(:cpk_great_author_first_book)
+    library << Cpk::Book.new(author_id: 1, number: 3)
+    library << Cpk::Book.new(author_id: 1, number: 3)
 
     # without primary key being set
     library << Cpk::Book.new(title: "Book A")
@@ -189,34 +170,22 @@ def test_composite_pk_models_added_to_a_set
   end
 
   def test_composite_pk_models_equality
-    book = cpk_books(:cpk_great_author_first_book)
-    book_instance_1 = Cpk::Book.find_by(author_id: book.author_id, number: book.number)
-    book_instance_2 = Cpk::Book.find_by(author_id: book.author_id, number: book.number)
-
-    assert book_instance_1 == book_instance_1
-    assert book_instance_1 == book_instance_2
+    assert Cpk::Book.new(author_id: 1, number: 2) == Cpk::Book.new(author_id: 1, number: 2)
 
-    # two new records with the same primary key
-    assert_not Cpk::Book.new(author_id: 1, number: 2) == Cpk::Book.new(author_id: 1, number: 2)
-    # two new records with an empty primary key values
+    assert_not Cpk::Book.new(author_id: 1, number: 2) == Cpk::Book.new(author_id: 1, number: 3)
     assert_not Cpk::Book.new == Cpk::Book.new
-    # two persisted records with a different primary key
-    assert_not cpk_books(:cpk_great_author_first_book) == cpk_books(:cpk_great_author_second_book)
+    assert_not Cpk::Book.new(title: "Book A") == Cpk::Book.new(title: "Book B")
+    assert_not Cpk::Book.new(author_id: 1) == Cpk::Book.new(author_id: 1)
+    assert_not Cpk::Book.new(author_id: 1, title: "Same title") == Cpk::Book.new(author_id: 1, title: "Same title")
   end
 
   def test_composite_pk_models_hash
-    book = cpk_books(:cpk_great_author_first_book)
-    book_instance_1 = Cpk::Book.find_by(author_id: book.author_id, number: book.number)
-    book_instance_2 = Cpk::Book.find_by(author_id: book.author_id, number: book.number)
-
-    assert_equal book_instance_1.hash, book_instance_1.hash
-    assert_equal book_instance_1.hash, book_instance_2.hash
+    assert_equal Cpk::Book.new(author_id: 1, number: 2).hash, Cpk::Book.new(author_id: 1, number: 2).hash
 
-    # two new records with the same primary key
-    assert_not_equal Cpk::Book.new(author_id: 1, number: 2).hash, Cpk::Book.new(author_id: 1, number: 2).hash
-    # two new records with an empty primary key values
+    assert_not_equal Cpk::Book.new(author_id: 1, number: 2).hash, Cpk::Book.new(author_id: 1, number: 3).hash
     assert_not_equal Cpk::Book.new.hash, Cpk::Book.new.hash
-    # two persisted records with a different primary key
-    assert_not_equal cpk_books(:cpk_great_author_first_book).hash, cpk_books(:cpk_great_author_second_book).hash
+    assert_not_equal Cpk::Book.new(title: "Book A").hash, Cpk::Book.new(title: "Book B").hash
+    assert_not_equal Cpk::Book.new(author_id: 1).hash, Cpk::Book.new(author_id: 1).hash
+    assert_not_equal Cpk::Book.new(author_id: 1, title: "Same title").hash, Cpk::Book.new(author_id: 1, title: "Same title").hash
   end
 end

activerecord/test/cases/filter_attributes_test.rb

@@ -68,7 +68,6 @@ class FilterAttributesTest < ActiveRecord::TestCase
     ActiveRecord::Base.filter_attributes = [ lambda { |key, value| value.reverse! if key == "name" } ]
     account = Admin::Account.new(id: 123, name: "37signals")
     account.inspect
-    account.save!
     assert_equal account, Marshal.load(Marshal.dump(account))
   end
 

activerecord/test/schema/schema.rb

@@ -1411,10 +1411,6 @@
     t.bigint :toooooooo_long_a_id, null: false
     t.bigint :toooooooo_long_b_id, null: false
   end
-
-  create_table :pk_with_defaults, id: false, force: true do |t|
-    t.bigint :id, default: 123
-  end
 end
 
 Course.connection.create_table :courses, force: true do |t|