Fix that JSON and XML exception responses should give the HTTP error message...

Fix that JSON and XML exception responses should give the HTTP error message for their status, by default, not the message from the underlying exception

actionpack/lib/action_dispatch/middleware/public_exceptions.rb

@@ -11,7 +11,7 @@ def call(env)
       status       = env["PATH_INFO"][1..-1]
       request      = ActionDispatch::Request.new(env)
       content_type = request.formats.first
-      body         = { :status => status, :error => exception.message }
+      body         = { :status => status, :error => Rack::Utils::HTTP_STATUS_CODES.fetch(status.to_i, Rack::Utils::HTTP_STATUS_CODES[500]) }
 
       render(status, content_type, body)
     end
@@ -19,7 +19,7 @@ def call(env)
     private
 
     def render(status, content_type, body)
-      format = content_type && "to_#{content_type.to_sym}"
+      format = "to_#{content_type.to_sym}" if content_type
       if format && body.respond_to?(format)
         render_format(status, content_type, body.public_send(format))
       else

actionpack/test/controller/show_exceptions_test.rb

@@ -75,7 +75,7 @@ def test_render_json_exception
       get "/", {}, 'HTTP_ACCEPT' => 'application/json'
       assert_response :internal_server_error
       assert_equal 'application/json', response.content_type.to_s
-      assert_equal({ :status => '500', :error => 'boom!' }.to_json, response.body)
+      assert_equal({ :status => '500', :error => 'Internal Server Error' }.to_json, response.body)
     end
 
     def test_render_xml_exception
@@ -83,7 +83,7 @@ def test_render_xml_exception
       get "/", {}, 'HTTP_ACCEPT' => 'application/xml'
       assert_response :internal_server_error
       assert_equal 'application/xml', response.content_type.to_s
-      assert_equal({ :status => '500', :error => 'boom!' }.to_xml, response.body)
+      assert_equal({ :status => '500', :error => 'Internal Server Error' }.to_xml, response.body)
     end
 
     def test_render_fallback_exception