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-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 8F3091F5AE for ; Fri, 24 Jul 2020 17:24:09 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id CE3CA12099F; Sat, 25 Jul 2020 02:23:35 +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 DFAC712099E for ; Sat, 25 Jul 2020 02:23:32 +0900 (JST) Received: by filterdrecv-p3iad2-5b55dcd864-622mb with SMTP id filterdrecv-p3iad2-5b55dcd864-622mb-16-5F1B192F-72 2020-07-24 17:23:59.862668424 +0000 UTC m=+2420080.172114697 Received: from herokuapp.com (unknown) by ismtpd0001p1iad1.sendgrid.net (SG) with ESMTP id vysAGZmRT42LkUceM-QvZQ for ; Fri, 24 Jul 2020 17:23:59.707 +0000 (UTC) Date: Fri, 24 Jul 2020 17:23:59 +0000 (UTC) From: XrXr@users.noreply.github.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 75104 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Bug X-Redmine-Issue-Id: 17048 X-Redmine-Issue-Author: alanwu X-Redmine-Sender: alanwu 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?PWg67P6owy8ojUUZg1G=2FQM4Z0jTQ2XLCqLM8Y2L8tUvRFuUPM6+aKANjRFY5CJ?= =?us-ascii?Q?rIRgb+nyxA7Hs=2Fdf9+z73zio=2F2Ta7ocW6d8k1iT?= =?us-ascii?Q?JFiYop42MZWqx=2FlRPRJG9DhmNrFxncejt4c3Yey?= =?us-ascii?Q?RKhF=2FrlOnSkxlYU9oIEILj7T2VU1gUd1exRJ=2F8y?= =?us-ascii?Q?eFUKR8pr76kmdL5rAmGb2Y97fy9prkCmWWs=2FbQa?= =?us-ascii?Q?P6DM15EMiXVzzwU5o=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 99313 Subject: [ruby-core:99313] [Ruby master Bug#17048] Calling initialize_copy on live modules leads to crashes 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 #17048 has been updated by alanwu (Alan Wu). I'm not proposing that we remove `initialize_copy`, but to make it raise when the receiver has children. So this is what it would look like: ```ruby module A end A.send(:initialize_copy, Module.new) # fine, no one inherits from A class B include A A.send(:initialize_copy, Module.new) # raise, since A now has one child end ``` Admittedly this proposed behavior is designed to sidestep the problem that the current implementation has. Though maybe it's fine since this is a seldom used private method and other Ruby implementations don't have to follow this behavior? Now that you've mentioned it, removing the method and moving the logic into `Module#{dup,clone}` feels like the cleanest solution. It's more likely to be a breaking change though. ---------------------------------------- Bug #17048: Calling initialize_copy on live modules leads to crashes https://bugs.ruby-lang.org/issues/17048#change-86707 * Author: alanwu (Alan Wu) * Status: Open * Priority: Normal * ruby -v: ruby 2.8.0dev (2020-07-23T14:44:25Z master 098e8c2873) [x86_64-linux] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- Here's a repro script ```ruby loop do m = Module.new do prepend Module.new def hello end end klass = Class.new { include m } m.send(:initialize_copy, Module.new) GC.start klass.new.hello rescue nil end ``` Here's a script that shows that it has broken semantics even when it happens to not crash. ```ruby module A end class B include A end module C Const = :C end module D Const = :D end A.send(:initialize_copy, C) p B::Const # :C, makes sense A.send(:initialize_copy, D) p B::Const # :D, makes sense A.send(:initialize_copy, Module.new) p (begin B::Const rescue NameError; 'NameError' end) # NameError, makes sense A.send(:initialize_copy, C) p B::Const # still NameErorr. Weird ``` This example shows that the problem exists [as far back as 2.0.0](https://wandbox.org/permlink/4dVDY9sNXJ803jh8). I think the easiest way to fix this is to forbid calling `:initialize_copy` on modules that have children. Another option is to try to decide on the semantics of this. Though I don't think it's worth the effort as this has been broken for a long time and people don't seem to to be using it. Thoughts? -- https://bugs.ruby-lang.org/