Deprecate alias_method_chain in favour of Module#prepend

…as discussed #19413

1 files changed, 125 insertions, 95 deletions

diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index c9c9b66a6c..bdfbadcf1d 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -358,148 +358,178 @@ class MethodAliasingTest < ActiveSupport::TestCase
     Object.instance_eval { remove_const :FooClassWithBarMethod }
   end
 
-  def test_alias_method_chain
-    assert @instance.respond_to?(:bar)
-    feature_aliases = [:bar_with_baz, :bar_without_baz]
+  def test_alias_method_chain_deprecated
+    assert_deprecated(/alias_method_chain/) do
+      Module.new do
+        def base
+        end
+
+        def base_with_deprecated
+        end
 
-    feature_aliases.each do |method|
-      assert !@instance.respond_to?(method)
+        alias_method_chain :base, :deprecated
+      end
     end
+  end
 
-    assert_equal 'bar', @instance.bar
+  def test_alias_method_chain
+    assert_deprecated(/alias_method_chain/) do
+      assert @instance.respond_to?(:bar)
+      feature_aliases = [:bar_with_baz, :bar_without_baz]
 
-    FooClassWithBarMethod.class_eval { include BarMethodAliaser }
+      feature_aliases.each do |method|
+        assert !@instance.respond_to?(method)
+      end
 
-    feature_aliases.each do |method|
-      assert_respond_to @instance, method
-    end
+      assert_equal 'bar', @instance.bar
+
+      FooClassWithBarMethod.class_eval { include BarMethodAliaser }
+
+      feature_aliases.each do |method|
+        assert_respond_to @instance, method
+      end
 
-    assert_equal 'bar_with_baz', @instance.bar
-    assert_equal 'bar', @instance.bar_without_baz
+      assert_equal 'bar_with_baz', @instance.bar
+      assert_equal 'bar', @instance.bar_without_baz
+    end
   end
 
   def test_alias_method_chain_with_punctuation_method
-    FooClassWithBarMethod.class_eval do
-      def quux!; 'quux' end
-    end
+    assert_deprecated(/alias_method_chain/) do
+      FooClassWithBarMethod.class_eval do
+        def quux!; 'quux' end
+      end
 
-    assert !@instance.respond_to?(:quux_with_baz!)
-    FooClassWithBarMethod.class_eval do
-      include BarMethodAliaser
-      alias_method_chain :quux!, :baz
-    end
-    assert_respond_to @instance, :quux_with_baz!
+      assert !@instance.respond_to?(:quux_with_baz!)
+      FooClassWithBarMethod.class_eval do
+        include BarMethodAliaser
+        alias_method_chain :quux!, :baz
+      end
+      assert_respond_to @instance, :quux_with_baz!
 
-    assert_equal 'quux_with_baz', @instance.quux!
-    assert_equal 'quux', @instance.quux_without_baz!
+      assert_equal 'quux_with_baz', @instance.quux!
+      assert_equal 'quux', @instance.quux_without_baz!
+    end
   end
 
   def test_alias_method_chain_with_same_names_between_predicates_and_bang_methods
-    FooClassWithBarMethod.class_eval do
-      def quux!; 'quux!' end
-      def quux?; true end
-      def quux=(v); 'quux=' end
-    end
+    assert_deprecated(/alias_method_chain/) do
+      FooClassWithBarMethod.class_eval do
+        def quux!; 'quux!' end
+        def quux?; true end
+        def quux=(v); 'quux=' end
+      end
 
-    assert !@instance.respond_to?(:quux_with_baz!)
-    assert !@instance.respond_to?(:quux_with_baz?)
-    assert !@instance.respond_to?(:quux_with_baz=)
+      assert !@instance.respond_to?(:quux_with_baz!)
+      assert !@instance.respond_to?(:quux_with_baz?)
+      assert !@instance.respond_to?(:quux_with_baz=)
 
-    FooClassWithBarMethod.class_eval { include BarMethodAliaser }
-    assert_respond_to @instance, :quux_with_baz!
-    assert_respond_to @instance, :quux_with_baz?
-    assert_respond_to @instance, :quux_with_baz=
+      FooClassWithBarMethod.class_eval { include BarMethodAliaser }
+      assert_respond_to @instance, :quux_with_baz!
+      assert_respond_to @instance, :quux_with_baz?
+      assert_respond_to @instance, :quux_with_baz=
 
 
-    FooClassWithBarMethod.alias_method_chain :quux!, :baz
-    assert_equal 'quux!_with_baz', @instance.quux!
-    assert_equal 'quux!', @instance.quux_without_baz!
+      FooClassWithBarMethod.alias_method_chain :quux!, :baz
+      assert_equal 'quux!_with_baz', @instance.quux!
+      assert_equal 'quux!', @instance.quux_without_baz!
 
-    FooClassWithBarMethod.alias_method_chain :quux?, :baz
-    assert_equal false, @instance.quux?
-    assert_equal true,  @instance.quux_without_baz?
+      FooClassWithBarMethod.alias_method_chain :quux?, :baz
+      assert_equal false, @instance.quux?
+      assert_equal true,  @instance.quux_without_baz?
 
-    FooClassWithBarMethod.alias_method_chain :quux=, :baz
-    assert_equal 'quux=_with_baz', @instance.send(:quux=, 1234)
-    assert_equal 'quux=', @instance.send(:quux_without_baz=, 1234)
+      FooClassWithBarMethod.alias_method_chain :quux=, :baz
+      assert_equal 'quux=_with_baz', @instance.send(:quux=, 1234)
+      assert_equal 'quux=', @instance.send(:quux_without_baz=, 1234)
+    end
   end
 
   def test_alias_method_chain_with_feature_punctuation
-    FooClassWithBarMethod.class_eval do
-      def quux; 'quux' end
-      def quux?; 'quux?' end
-      include BarMethodAliaser
-      alias_method_chain :quux, :baz!
-    end
+    assert_deprecated(/alias_method_chain/) do
+      FooClassWithBarMethod.class_eval do
+        def quux; 'quux' end
+        def quux?; 'quux?' end
+        include BarMethodAliaser
+        alias_method_chain :quux, :baz!
+      end
 
-    assert_nothing_raised do
-      assert_equal 'quux_with_baz', @instance.quux_with_baz!
-    end
+      assert_nothing_raised do
+        assert_equal 'quux_with_baz', @instance.quux_with_baz!
+      end
 
-    assert_raise(NameError) do
-      FooClassWithBarMethod.alias_method_chain :quux?, :baz!
+      assert_raise(NameError) do
+        FooClassWithBarMethod.alias_method_chain :quux?, :baz!
+      end
     end
   end
 
   def test_alias_method_chain_yields_target_and_punctuation
-    args = nil
+    assert_deprecated(/alias_method_chain/) do
+      args = nil
 
-    FooClassWithBarMethod.class_eval do
-      def quux?; end
-      include BarMethods
+      FooClassWithBarMethod.class_eval do
+        def quux?; end
+        include BarMethods
 
-      FooClassWithBarMethod.alias_method_chain :quux?, :baz do |target, punctuation|
-        args = [target, punctuation]
+        FooClassWithBarMethod.alias_method_chain :quux?, :baz do |target, punctuation|
+          args = [target, punctuation]
+        end
       end
-    end
 
-    assert_not_nil args
-    assert_equal 'quux', args[0]
-    assert_equal '?', args[1]
+      assert_not_nil args
+      assert_equal 'quux', args[0]
+      assert_equal '?', args[1]
+    end
   end
 
   def test_alias_method_chain_preserves_private_method_status
-    FooClassWithBarMethod.class_eval do
-      def duck; 'duck' end
-      include BarMethodAliaser
-      private :duck
-      alias_method_chain :duck, :orange
-    end
+    assert_deprecated(/alias_method_chain/) do
+      FooClassWithBarMethod.class_eval do
+        def duck; 'duck' end
+        include BarMethodAliaser
+        private :duck
+        alias_method_chain :duck, :orange
+      end
 
-    assert_raise NoMethodError do
-      @instance.duck
-    end
+      assert_raise NoMethodError do
+        @instance.duck
+      end
 
-    assert_equal 'duck_with_orange', @instance.instance_eval { duck }
-    assert FooClassWithBarMethod.private_method_defined?(:duck)
+      assert_equal 'duck_with_orange', @instance.instance_eval { duck }
+      assert FooClassWithBarMethod.private_method_defined?(:duck)
+    end
   end
 
   def test_alias_method_chain_preserves_protected_method_status
-    FooClassWithBarMethod.class_eval do
-      def duck; 'duck' end
-      include BarMethodAliaser
-      protected :duck
-      alias_method_chain :duck, :orange
-    end
+    assert_deprecated(/alias_method_chain/) do
+      FooClassWithBarMethod.class_eval do
+        def duck; 'duck' end
+        include BarMethodAliaser
+        protected :duck
+        alias_method_chain :duck, :orange
+      end
 
-    assert_raise NoMethodError do
-      @instance.duck
-    end
+      assert_raise NoMethodError do
+        @instance.duck
+      end
 
-    assert_equal 'duck_with_orange', @instance.instance_eval { duck }
-    assert FooClassWithBarMethod.protected_method_defined?(:duck)
+      assert_equal 'duck_with_orange', @instance.instance_eval { duck }
+      assert FooClassWithBarMethod.protected_method_defined?(:duck)
+    end
   end
 
   def test_alias_method_chain_preserves_public_method_status
-    FooClassWithBarMethod.class_eval do
-      def duck; 'duck' end
-      include BarMethodAliaser
-      public :duck
-      alias_method_chain :duck, :orange
-    end
+    assert_deprecated(/alias_method_chain/) do
+      FooClassWithBarMethod.class_eval do
+        def duck; 'duck' end
+        include BarMethodAliaser
+        public :duck
+        alias_method_chain :duck, :orange
+      end
 
-    assert_equal 'duck_with_orange', @instance.duck
-    assert FooClassWithBarMethod.public_method_defined?(:duck)
+      assert_equal 'duck_with_orange', @instance.duck
+      assert FooClassWithBarMethod.public_method_defined?(:duck)
+    end
   end
 
   def test_delegate_with_case