4 files changed, 35 insertions, 2 deletions
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index fb31c85d0c..c2570f743e 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,16 @@
+*   Delegate `empty?`, `none?` and `one?`. Now they can be invoked as model class methods.
+
+    Example:
+
+        # When no record is found on the table
+        Topic.empty? # => true
+        Topic.none?  # => true
+
+        # When only one record is found on the table
+        Topic.one?   # => true
+
+    *Kenta Shirai*
+
 *   The form builder now properly displays values when passing a proc form
     default to the attributes API.
 
diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index 09d55adcd7..a20d7e0820 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -57,7 +57,7 @@ module ActiveRecord
         def index_exists?(table_name, column_name, options = {})
           column_names = Array(column_name).map(&:to_s)
           options[:name] =
-            if options.key?(:name).present?
+            if options[:name].present?
               options[:name].to_s
             else
               index_name(table_name, column: column_names)
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
index de5b42e987..4e32d73001 100644
--- a/activerecord/lib/active_record/querying.rb
+++ b/activerecord/lib/active_record/querying.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module Querying
-    delegate :find, :take, :take!, :first, :first!, :last, :last!, :exists?, :any?, :many?, to: :all
+    delegate :find, :take, :take!, :first, :first!, :last, :last!, :exists?, :any?, :many?, :empty?, :none?, :one?, to: :all
     delegate :second, :second!, :third, :third!, :fourth, :fourth!, :fifth, :fifth!, :forty_two, :forty_two!, :third_to_last, :third_to_last!, :second_to_last, :second_to_last!, to: :all
     delegate :first_or_create, :first_or_create!, :first_or_initialize, to: :all
     delegate :find_or_create_by, :find_or_create_by!, :find_or_initialize_by, to: :all
diff --git a/activerecord/test/cases/scoping/named_scoping_test.rb b/activerecord/test/cases/scoping/named_scoping_test.rb
index acba97bbb8..96c94eefa0 100644
--- a/activerecord/test/cases/scoping/named_scoping_test.rb
+++ b/activerecord/test/cases/scoping/named_scoping_test.rb
@@ -544,4 +544,24 @@ class NamedScopingTest < ActiveRecord::TestCase
     assert_equal 1, SpecialComment.where(body: 'go crazy').created.count
   end
 
+  def test_model_class_should_respond_to_empty
+    assert !Topic.empty?
+    Topic.delete_all
+    assert Topic.empty?
+  end
+
+  def test_model_class_should_respond_to_none
+    assert !Topic.none?
+    Topic.delete_all
+    assert Topic.none?
+  end
+
+  def test_model_class_should_respond_to_one
+    assert !Topic.one?
+    Topic.delete_all
+    assert !Topic.one?
+    Topic.create!
+    assert Topic.one?
+  end
+
 end