Revert "MONGOID-5822: Embedded association validations break when association depends on parent update (#5922)"

This reverts commit ec18c8b.

MONGOID-5822 introduced an unacceptable performance regression.

Author: jamis

lib/mongoid/validatable/associated.rb

@@ -74,7 +74,7 @@ def validate_association(document, attribute)
           # use map.all? instead of just all?, because all? will do short-circuit
           # evaluation and terminate on the first failed validation.
           list.map do |value|
-            if value && !value.flagged_for_destroy?
+            if value && !value.flagged_for_destroy? && (!value.persisted? || value.changed?)
               value.validated? ? true : value.valid?
             else
               true

spec/mongoid/association_spec.rb

@@ -115,66 +115,6 @@ class AssocationSpecModel
         expect(name).to_not be_an_embedded_many
       end
     end
-
-    context "when validation depends on association" do
-      before(:all) do
-        class Author
-          include Mongoid::Document
-          embeds_many :books, cascade_callbacks: true
-          field :condition, type: Boolean
-        end
-
-        class Book
-          include Mongoid::Document
-          embedded_in :author
-          validate :parent_condition_is_not_true
-
-          def parent_condition_is_not_true
-            return unless author&.condition
-            errors.add :base, "Author condition is true."
-          end
-        end
-
-        Author.delete_all
-        Book.delete_all
-      end
-
-      let(:author) { Author.new }
-      let(:book) { Book.new }
-
-      context "when author is not persisted" do
-        it "is valid without books" do
-          expect(author.valid?).to be true
-        end
-
-        it "is valid with a book" do
-          author.books << book
-          expect(author.valid?).to be true
-        end
-
-        it "is not valid when condition is true with a book" do
-          author.condition = true
-          author.books << book
-          expect(author.valid?).to be false
-        end
-      end
-
-      context "when author is persisted" do
-        before do
-          author.books << book
-          author.save
-        end
-
-        it "remains valid initially" do
-          expect(author.valid?).to be true
-        end
-
-        it "becomes invalid when condition is set to true" do
-          author.update_attributes(condition: true)
-          expect(author.valid?).to be false
-        end
-      end
-    end
   end
 
   describe "#embedded_one?" do