From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-1.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=no autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id DB6161F463 for ; Thu, 12 Sep 2019 12:53:43 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 68A69120A05; Thu, 12 Sep 2019 21:53:31 +0900 (JST) Received: from o1678948x4.outbound-mail.sendgrid.net (o1678948x4.outbound-mail.sendgrid.net [167.89.48.4]) by neon.ruby-lang.org (Postfix) with ESMTPS id 5BD06120A05 for ; Thu, 12 Sep 2019 21:53:27 +0900 (JST) Received: by filter0194p3mdw1.sendgrid.net with SMTP id filter0194p3mdw1-32190-5D7A3FC7-56 2019-09-12 12:53:27.966850489 +0000 UTC m=+155988.381781830 Received: from herokuapp.com (unknown [54.242.45.138]) by ismtpd0004p1iad1.sendgrid.net (SG) with ESMTP id f-v1KsgOTj-UtfTG-Mgo1A for ; Thu, 12 Sep 2019 12:53:27.934 +0000 (UTC) Date: Thu, 12 Sep 2019 12:53:28 +0000 (UTC) From: daniel@dan42.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 70476 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 16157 X-Redmine-Issue-Author: Dan0042 X-Redmine-Sender: Dan0042 X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: =?us-ascii?Q?8sy4RigFvRTdBfCVJrT9zb2J88PC92TMQwdNgaWYaq5ILiwCNk9854tZfSQGsV?= =?us-ascii?Q?omckPIqQ2vlT5c64vcGScVwMDJZuWVGAmy8mfiT?= =?us-ascii?Q?E5dmTednN1g3Z1G+vmkMHdnX1VsaPmNkw+tDIhb?= =?us-ascii?Q?JYaL3SGyvmq=2FDlN3cjWMVGvODQoQLUzJFsyeuRY?= =?us-ascii?Q?88XhGhiEZBn+QywR+uCH6AoRcVujsoKkYaA=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 94922 Subject: [ruby-core:94922] [Ruby master Misc#16157] What is the correct and *portable* way to do generic delegation? X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #16157 has been updated by Dan0042 (Daniel DeLorme). After some more thinking I believe the `pass_keywords` behavior would be appropriate for 100% of methods with an argument splat but no keywords. * If forwarding to a method with no keyword arguments * The kwarg will be converted to positional hash anyway * If forwarding to a method with keyword arguments * If the intention is to pass a kwarg * Will work as expected * If the intention is to pass a positional hash * This behavior is currently impossible in 2.6, so there would be no compatibility problem. In order to activate the new behavior of passing a positional hash, use `pass_keywords_as_hash` or whatever the name would be. ---------------------------------------- Misc #16157: What is the correct and *portable* way to do generic delegation? https://bugs.ruby-lang.org/issues/16157#change-81537 * Author: Dan0042 (Daniel DeLorme) * Status: Open * Priority: Normal * Assignee: ---------------------------------------- With the keyword argument changes in 2.7 we must now specify keyword arguments explicitly when doing generic delegation. But this change is not compatible with 2.6, where it adds an empty hash to the argument list of methods that do not need/accept keyword arguments. To illustrate the problem: ```ruby class ProxyWithoutKW < BasicObject def initialize(target) @target = target end def method_missing(*a, &b) @target.send(*a, &b) end end class ProxyWithKW < BasicObject def initialize(target) @target = target end def method_missing(*a, **o, &b) @target.send(*a, **o, &b) end end class Test def args(*a) a end def arg(a) a end def opts(**o) o end end # 2.6 2.7 3.0 ProxyWithoutKW.new(Test.new).args(42) # [42] [42] [42] ok ProxyWithoutKW.new(Test.new).arg(42) # 42 42 42 ok ProxyWithoutKW.new(Test.new).opts(k: 42) # {:k=>42} {:k=>42} +warn [{:k=>42}] incompatible with >= 2.7 ProxyWithKW.new(Test.new).args(42) # [42, {}] [42] [42] incompatible with <= 2.6 ProxyWithKW.new(Test.new).arg(42) # error 42 42 incompatible with <= 2.6 ProxyWithKW.new(Test.new).opts(k: 42) # {:k=>42} {:k=>42} +warn {:k=>42} must ignore warning? cannot use pass_positional_hash in 2.6 ``` I don't know how to solve this, so I'm asking for the **official** correct way to write portable delegation code. And by **portable** I mean code that can be used in gems that target ruby 2.6 and above. -- https://bugs.ruby-lang.org/