Collapsed dual checks (one for content headers and one for content) into a single check.

Rails includes a single character body to a head(:no_content) response to work around an old Safari bug where headers were ignored if no body sent.

This patch brings the behavior slightly closer to spec if :no_content/204 is explicity requested via a head only response.

Status comparison done on symbolic and numeric values

Not returning any content when responding with head and limited to a status code that explicitly states no content will be returned - 100..199, 204, 205, 304.

actionpack/lib/action_controller/metal/head.rb

@@ -29,19 +29,19 @@ def head(status, options = {})
       self.status = status
       self.location = url_for(location) if location
 
-      if include_content_headers?(self.status)
+      if include_content?(self.status)
         self.content_type = content_type || (Mime[formats.first] if formats)
+        self.response_body = " "
       else
         headers.delete('Content-Type')
         headers.delete('Content-Length')
+        self.response_body = ""
       end
-
-      self.response_body = " "
     end
 
     private
     # :nodoc:
-    def include_content_headers?(status)
+    def include_content?(status)
       case status
       when 100..199
         false

actionpack/test/controller/mime_responds_test.rb

@@ -850,7 +850,7 @@ def test_using_resource_for_put_with_xml_yields_no_content_on_success
     put :using_resource
     assert_equal "application/xml", @response.content_type
     assert_equal 204, @response.status
-    assert_equal " ", @response.body
+    assert_equal "", @response.body
   end
 
   def test_using_resource_for_put_with_json_yields_no_content_on_success
@@ -859,7 +859,7 @@ def test_using_resource_for_put_with_json_yields_no_content_on_success
     put :using_resource
     assert_equal "application/json", @response.content_type
     assert_equal 204, @response.status
-    assert_equal " ", @response.body
+    assert_equal "", @response.body
   end
 
   def test_using_resource_for_put_with_xml_yields_unprocessable_entity_on_failure
@@ -901,7 +901,7 @@ def test_using_resource_for_delete_with_xml_yields_no_content_on_success
     delete :using_resource
     assert_equal "application/xml", @response.content_type
     assert_equal 204, @response.status
-    assert_equal " ", @response.body
+    assert_equal "", @response.body
   end
 
   def test_using_resource_for_delete_with_json_yields_no_content_on_success
@@ -911,7 +911,7 @@ def test_using_resource_for_delete_with_json_yields_no_content_on_success
     delete :using_resource
     assert_equal "application/json", @response.content_type
     assert_equal 204, @response.status
-    assert_equal " ", @response.body
+    assert_equal "", @response.body
   end
 
   def test_using_resource_for_delete_with_html_redirects_on_failure

actionpack/test/controller/new_base/bare_metal_test.rb

@@ -110,6 +110,36 @@ class HeadTest < ActiveSupport::TestCase
       assert_nil headers['Content-Type']
       assert_nil headers['Content-Length']
     end
+
+    test "head :no_content (204) does not return any content" do
+      content = HeadController.action(:no_content).call(Rack::MockRequest.env_for("/")).third.first
+      assert_empty content
+    end
+
+    test "head :reset_content (205) does not return any content" do
+      content = HeadController.action(:reset_content).call(Rack::MockRequest.env_for("/")).third.first
+      assert_empty content
+    end
+
+    test "head :not_modified (304) does not return any content" do
+      content = HeadController.action(:not_modified).call(Rack::MockRequest.env_for("/")).third.first
+      assert_empty content
+    end
+
+    test "head :continue (100) does not return any content" do
+      content = HeadController.action(:continue).call(Rack::MockRequest.env_for("/")).third.first
+      assert_empty content
+    end
+
+    test "head :switching_protocols (101) does not return any content" do
+      content = HeadController.action(:switching_protocols).call(Rack::MockRequest.env_for("/")).third.first
+      assert_empty content
+    end
+
+    test "head :processing (102) does not return any content" do
+      content = HeadController.action(:processing).call(Rack::MockRequest.env_for("/")).third.first
+      assert_empty content
+    end
   end
 
   class BareControllerTest < ActionController::TestCase