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=-4.1 required=3.0 tests=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 A7C261F463 for ; Tue, 10 Sep 2019 14:41:15 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id B1508120A12; Tue, 10 Sep 2019 23:41:05 +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 70889120968 for ; Tue, 10 Sep 2019 23:41:03 +0900 (JST) Received: by filter0085p3las1.sendgrid.net with SMTP id filter0085p3las1-27498-5D77B600-74 2019-09-10 14:41:05.102776089 +0000 UTC m=+76966.486566132 Received: from herokuapp.com (unknown [54.210.152.167]) by ismtpd0010p1iad2.sendgrid.net (SG) with ESMTP id ex0SfHVRTEqV0h_xcNvoyQ for ; Tue, 10 Sep 2019 14:41:04.806 +0000 (UTC) Date: Tue, 10 Sep 2019 14:41:05 +0000 (UTC) From: daniel@dan42.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 70442 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?8sy4RigFvRTdBfCVJrT9zb2J88PC92TMQwdNgaWYaq4Ms9wkxba20j4KrXIqc8?= =?us-ascii?Q?cq6dphRj39=2F1QdebhwEiwJid2SzlukxJv8YB1cm?= =?us-ascii?Q?nRQrWdzRVavpSoqOVDiTu3t8XuQxvW7DlNPpnES?= =?us-ascii?Q?onnPIdtOhCfoMbnRomwd7VaVEfFkhyWVEOx3Jzx?= =?us-ascii?Q?0Mdw947OViaelv9r5S7NJtpTZFeG50eSO+w=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 94888 Subject: [ruby-core:94888] [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). Hmm, ok, that's what I was afraid of. I mean, it's not exactly a pretty solution. And it's not limited to method_missing; any method that accepts `*args` and forwards it to another method may have to be changed. Even if it doesn't have to be changed, it has to be checked, which is possibly even more work than a simple find-and-replace. One example that comes to mind is in the stdlib; all the files in json/add/*.rb have something like this which may need to be updated: ```ruby def to_json(*args) as_json.to_json(*args) end ``` Of course since that's the stdlib we don't need the RUBY_VERSION check, but for rubygems.... the issue is really how much is there to fix? If it's a small amount, even an ugly-ish solution can be good enough. Actually, this could be checked lexically to some extent... [workworkwork] I've compiled a list of the most popular gems by number of downloads. https://pastebin.com/MurhpP2j And then installed the top 500. Including pre-installed gems and dependencies, this results in 679 gems (including a few multiple versions). https://pastebin.com/KajXEt7A Then I search through all .rb files for methods that should be checked and/or updated to use the RUBY_VERSION check if they want to stay compatible with 2.6. https://pastebin.com/cmmjMDW8 Result: in `gems/*/lib`: 1949 matches in 1095 files of 225 gems: https://pastebin.com/HNU1cZcD in `gems/*/others`: 256 matches in 167 files of 63 gems: https://pastebin.com/eTciQAc0 That's... a **lot** more than I expected. And only with the top 500 gems. If you can check my methodology... But if I'm correct, I think that the migration required for syntax-based keyword separation goes beyond "challenging" and into the realm of "unrealistic". Of course that's a decision for Matz to take... ---------------------------------------- Misc #16157: What is the correct and *portable* way to do generic delegation? https://bugs.ruby-lang.org/issues/16157#change-81502 * 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/