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=AWL,BAYES_00, 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 8AABD1F8C8 for ; Thu, 16 Sep 2021 21:00:43 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 551D71209A0; Fri, 17 Sep 2021 05:59:18 +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 7D7A2120988 for ; Fri, 17 Sep 2021 05:59:16 +0900 (JST) Received: by filterdrecv-canary-6758d84484-dc5hn with SMTP id filterdrecv-canary-6758d84484-dc5hn-1-6143B070-24 2021-09-16 21:00:32.157920106 +0000 UTC m=+1372524.500760914 Received: from herokuapp.com (unknown) by geopod-ismtpd-5-1 (SG) with ESMTP id BKrWXYB_Q8iIhXTJFnOxew for ; Thu, 16 Sep 2021 21:00:32.024 +0000 (UTC) Date: Thu, 16 Sep 2021 21:00:32 +0000 (UTC) From: "alanwu (Alan Wu)" Message-ID: References: Mime-Version: 1.0 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-Redmine-MailingListIntegration-Message-Ids: 81490 X-SG-EID: =?us-ascii?Q?WlXRPNHxHGFfdcQPJIrfDE3RfQp6=2FL4iLf2SoiTsluUkfWCqAJLU=2FcY9pnqY3l?= =?us-ascii?Q?28iupwvwMlsqVgvX2LBzrptwOuP0tjnwdpqJVNj?= =?us-ascii?Q?bknhmIvnmPEsbjs5M3jpz1w0aCiJ=2FmBz11iMd+K?= =?us-ascii?Q?Oq=2FquutWmz4qT8Tjc=2FnRB2RDcfIEJRp1O8l2gCh?= =?us-ascii?Q?JolLrrZYdvGb6QcEK1nesuMlGUbSpNiVXwiO3Ww?= =?us-ascii?Q?tEWiO9h6yKsCbX4UwwofbnJVpt=2F4w5W3f+phCxb?= =?us-ascii?Q?LSx7TVPlkLLXk1jja8MlQ=3D=3D?= To: ruby-core@ruby-lang.org X-Entity-ID: b/2+PoftWZ6GuOu3b0IycA== X-ML-Name: ruby-core X-Mail-Count: 105314 Subject: [ruby-core:105314] [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). Here a repro that that always crashes for me on cbbda3e: ```ruby mod = Module.new { define_method(:foo) {:first} } klass = Class.new { include mod } instance = klass.new p instance.foo new_mod = Module.new { define_method(:foo) { :second } } mod.send(:initialize_copy, new_mod) 4.times { GC.start } p instance.foo # [BUG] unreachable ``` ---------------------------------------- Bug #17048: Calling initialize_copy on live modules leads to crashes https://bugs.ruby-lang.org/issues/17048#change-93727 * 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/