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 6C7351F45A for ; Tue, 13 Aug 2019 13:21:31 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 89208120A7A; Tue, 13 Aug 2019 22:21:23 +0900 (JST) Received: from o1678916x28.outbound-mail.sendgrid.net (o1678916x28.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 86B87120A64 for ; Tue, 13 Aug 2019 22:21:20 +0900 (JST) Received: by filter0189p3mdw1.sendgrid.net with SMTP id filter0189p3mdw1-28570-5D52B952-23 2019-08-13 13:21:22.573575433 +0000 UTC m=+1534875.842964488 Received: from herokuapp.com (unknown [54.224.29.177]) by ismtpd0038p1iad2.sendgrid.net (SG) with ESMTP id Bvde9ymeS9KgVypQn4brHg for ; Tue, 13 Aug 2019 13:21:22.501 +0000 (UTC) Date: Tue, 13 Aug 2019 13:21:22 +0000 (UTC) From: deivid.rodriguez@riseup.net Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 69871 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 15912 X-Redmine-Issue-Author: deivid X-Redmine-Issue-Assignee: ko1 X-Redmine-Sender: deivid 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?klzXTY0v3jOvaMSihdVenmzxCeXPrK4t1AV7GwiE8Thd3sUxBh4JuGHTAn51xb?= =?us-ascii?Q?3w06NP0Ytlomw5CfPa9+jzWqy5bb0CaTt4WvwIz?= =?us-ascii?Q?6Rxvupc+Ev8AldAEDyS6fMWG2SCkmMwo4toC8md?= =?us-ascii?Q?CGJ5d23+eBwWeq3QV3h11UxdoN2Cx4bWnM6ANbi?= =?us-ascii?Q?3QVzkgQxkWHUWWbDo=2FFklVd2=2FNfpWLXPV4w=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 94324 Subject: [ruby-core:94324] [Ruby master Feature#15912] Allow some reentrancy during TracePoint events 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="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #15912 has been updated by deivid (David Rodr=EDguez). Yes, that was initial proposal (to prohibit other events of the same type, = while a handler for a certain event type is running). But then I thought th= at we could even allow events of the same type, as long as we forbid handle= rs currently being run from being triggered. So in my example, line_handler2 executions in lines 5 and 7 would not run l= ine_handler1, but the execution in line 8 would run it (twice, actually). ``` 1: * main 2: * :line event 3: * line_handler1 4: * :line event 5: * line_handler2 6: * :line event 7: * line_handler2 8: * line_handler2 9: * :line event 10: * line_handler1 11: * :line event 12: * line_handler1 13: * finish all line hooks 14: * continue main ``` The idea is running any possible relevant event handler as long as it's not= already in the stack of event handlers currently being run. ---------------------------------------- Feature #15912: Allow some reentrancy during TracePoint events https://bugs.ruby-lang.org/issues/15912#change-80712 * Author: deivid (David Rodr=EDguez) * Status: Assigned * Priority: Normal * Assignee: ko1 (Koichi Sasada) * Target version: = ---------------------------------------- I got a report in byebug about byebug being incompatible with zeitwerk. Thi= s one: https://github.com/deivid-rodriguez/byebug/issues/564. This is a pro= blem because zeitwerk is the default Rails code loader, and byebug is the d= efault Rails debugger. Both of these tools rely on the TracePoint API: * Byebug uses a bunch of TracePoint events to stop execution at certain poi= nts in your program. * Zeitwek uses `:class` events to be able to resolve some circular edge cas= es. I investigated the problem and I think the issue is that while stopped at t= he byebug prompt, we're actually in the middle of processing a TracePoint e= vent. That means that further TracePoint events triggered at the byebug's p= rompt will be ignored, because otherwise we could get into an infinite loop= where the handling of events would trigger more events that trigger themse= lves the execution of handlers again. I understand why the TracePoint API does this, but if we could allow some l= evel of reentrancy here, we could probably make these tools play nice toget= her. I figure if we kept a stack of TracePoint event handlers being run, an= d check that the current event type is not already in the stack, we would a= llow :class events to be triggered from :line events, and I think that woul= d allow Zeitwerk to work within byebug. What do you think about this, @ko1? -- = https://bugs.ruby-lang.org/ Unsubscribe: