Fix AC::Parameters#== with other AC::Parameters

Creating a protected getter method for `@parameters`.

actionpack/lib/action_controller/metal/strong_parameters.rb

@@ -144,11 +144,10 @@ module ActionController
     end
 
     # Returns true if another +Parameters+ object contains the same content and
-    # permitted flag, or other Hash-like object contains the same content. This
-    # override is in place so you can perform a comparison with `Hash`.
+    # permitted flag, or other Hash-like object contains the same content.
     def ==(other_hash)
       if other_hash.respond_to?(:permitted?)
-        super
+        self.permitted? == other_hash.permitted? && self.parameters == other_hash.parameters
       else
         if other_hash.is_a?(Hash)
           @parameters == other_hash.with_indifferent_access
@@ -597,6 +596,8 @@ module ActionController
     end
 
     protected
+      attr_reader :parameters
+
       def permitted=(new_permitted)
         @permitted = new_permitted
       end

actionpack/test/controller/parameters/accessors_test.rb

@@ -135,6 +135,39 @@ class ParametersAccessorsTest < ActiveSupport::TestCase
     assert(params1 == hash1)
   end
 
+  test "is equal to Parameters instance with same params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2)
+    params2 = ActionController::Parameters.new(a: 1, b: 2)
+    assert(params1 == params2)
+  end
+
+  test "is equal to Parameters instance with same permitted params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    params2 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    assert(params1 == params2)
+  end
+
+  test "is equal to Parameters instance with same different source params, but same permitted params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    params2 = ActionController::Parameters.new(a: 1, c: 3).permit(:a)
+    assert(params1 == params2)
+    assert(params2 == params1)
+  end
+
+  test 'is not equal to an unpermitted Parameters instance with same params' do
+    params1 = ActionController::Parameters.new(a: 1).permit(:a)
+    params2 = ActionController::Parameters.new(a: 1)
+    assert(params1 != params2)
+    assert(params2 != params1)
+  end
+
+  test "is not equal to Parameters instance with different permitted params" do
+    params1 = ActionController::Parameters.new(a: 1, b: 2).permit(:a, :b)
+    params2 = ActionController::Parameters.new(a: 1, b: 2).permit(:a)
+    assert(params1 != params2)
+    assert(params2 != params1)
+  end
+
   test "equality with simple types works" do
     assert(@params != 'Hello')
     assert(@params != 42)