Silver: is and as? operator does work with extensions of base

hurden · September 29, 2016, 12:32pm

IDE: Fire
Version: 8.4.96.2043
Target (If relevant): Java
Description:

After extending java.io.File and making it comply to protocol is and as? operators will fail to identify the instance as being of type java.io.File.
When creating my own class, extending, and making it comply to the very same protocol, works fine.

Compiler generated extension subclass:

entity: lakestonecore.tests.__Extension_File$Duck_File_AnyFileOrDirectory

code (TestDirectory.swift):

for entity in testDirectory.filesAndSubdirectories {
	if entity.isDirectory {
		Assert.IsTrue(entity is Directory)
	} else {
                 //fails here
		//Assert.IsTrue(entity is File)
	}
}

Actual code can be found here:

github.com

GeoThings/LakestoneCore/blob/master/Source/File.swift

//
//  File.swift
//  LakestoneCore
//
//  Created by Taras Vozniuk on 9/28/16.
//  Copyright © 2016 GeoThings. All rights reserved.
//
// --------------------------------------------------------
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

This file has been truncated. show original

ck · September 29, 2016, 12:46pm

We’ve got some ideas on how to solve this in a limited way, ie if you have the interfaces it can allow casting back, but it won’t work as say Object -> File when originating as a AnyFileOrDrecitory.

RemObjectsSoftware · September 29, 2016, 12:46pm

Thanks, logged as bugs://76302

hurden · September 29, 2016, 4:45pm

Yeah, right. It’s not a big deal, I only intented using is type check for this API in unit test case, but overall I guess it might be more or less common issue.

RemObjectsSoftware · April 11, 2018, 6:51am

bugs://76302 got closed with status fixed.

ck · April 11, 2018, 6:52am

So this works (well partially); when you have a File and cast it to AnyFileOrDirectory (which is an extension) it works, is works too. When you have an Object/Any containing a File it won’t work unfortunately, that’s a runtime limitation.