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=-4.0 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham 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 14FC71F461 for ; Mon, 9 Sep 2019 14:22:28 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 37F13120A0C; Mon, 9 Sep 2019 23:22:18 +0900 (JST) Received: from xtrwkhkc.outbound-mail.sendgrid.net (xtrwkhkc.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 120B9120914 for ; Mon, 9 Sep 2019 23:22:15 +0900 (JST) Received: by filter0052p3las1.sendgrid.net with SMTP id filter0052p3las1-15974-5D766017-3B 2019-09-09 14:22:15.908184406 +0000 UTC m=+510884.744579335 Received: from herokuapp.com (unknown [3.86.63.147]) by ismtpd0036p1iad1.sendgrid.net (SG) with ESMTP id 2U3Rc7IbQSalG1vySdWSHA for ; Mon, 09 Sep 2019 14:22:15.891 +0000 (UTC) Date: Mon, 09 Sep 2019 14:22:16 +0000 (UTC) From: merch-redmine@jeremyevans.net Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 70416 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 16157 X-Redmine-Issue-Author: Dan0042 X-Redmine-Sender: jeremyevans0 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?RVE3t853K5scBhbmJHUzZTFFeVC=2FZSUmHZ0Dc+26wcEi2CTgsF1oz0wTSSxGGN?= =?us-ascii?Q?BI5Tlm=2FdWLgd8gwkP06MG2y6yty11XrcFixLCOc?= =?us-ascii?Q?MSYTHgIEqpV4fB1CubdnFC+8XTtpFtqrZzcsrB8?= =?us-ascii?Q?6tXCf8uVz8ax1v+9DOyGJWdQFVj2lpiy=2F6ZYHip?= =?us-ascii?Q?YsuD8642T8yyriOX=2FFe12COOyaCCcv5z2nw=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 94861 Subject: [ruby-core:94861] [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 jeremyevans0 (Jeremy Evans). I haven't tested this, but I think it should work the same between 2.0 - 3.0 (assuming #16154 is accepted): ```ruby class ProxyWithKW < BasicObject def initialize(target) @target = target end def method_missing(*a, **o, &b) if o.empty? @target.send(*a, &b) else @target.send(*a, **o, &b) end end pass_positional_hash(:method_missing) if respond_to?(:pass_positional_hash, false) end ``` ---------------------------------------- Misc #16157: What is the correct and *portable* way to do generic delegation? https://bugs.ruby-lang.org/issues/16157#change-81480 * 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/