From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on starla X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 Received: from nue.mailmanlists.eu (nue.mailmanlists.eu [94.130.110.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 9AF02D4809 for ; Thu, 13 Jun 2024 04:28:59 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=Qc2G1YLM; dkim-atps=neutral Received: from nue.mailmanlists.eu (localhost [IPv6:::1]) by nue.mailmanlists.eu (Postfix) with ESMTP id 048EE43A9E for ; Thu, 13 Jun 2024 04:28:27 +0000 (UTC) Received: from s.wrqvtvvn.outbound-mail.sendgrid.net (s.wrqvtvvn.outbound-mail.sendgrid.net [149.72.120.130]) by nue.mailmanlists.eu (Postfix) with ESMTPS id AFA01437AB for ; Thu, 13 Jun 2024 04:28:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ruby-lang.org; h=from:references:subject:mime-version:content-type: content-transfer-encoding:list-id:to:cc:content-type:from:subject:to; s=s1; bh=TWAsV2AGghbrdNTRU3VKbpwNFU8EbJ6m7vlxVXP9L/4=; b=Qc2G1YLM5aI/VYAGo8Z2r0MYryIc/Bk79yIhzc+hWAtDM7WurLr0HST9RfR/8+vryrVE cKrLWBeFNeIWEhOCG0gp6TRMqSbsufJBZcoBvG0YWrFCwusq5o0JxjwwVVGJiG0m33gT1V tWiNhuuW2gqXZ7y5sJIm/jmBNfO3Rg2baK0Qx7il7nIUbkinzAD38QCZ1CB27KR+f+492J sFIxwzTdBjHUcH/o3xQ4fz6qo9hYdC+x+8kSHYivQUCdLuIhXLkQpFRV+xKosyPn54dD19 FRFARMZXmgQkf+ymcDqY8ujblRfe2bWg1WH3U6HA+WCZjW3kkVavYkWp+hZD8a1g== Received: by recvd-67fdc7b4d6-gktx2 with SMTP id recvd-67fdc7b4d6-gktx2-1-666A755B-16 2024-06-13 04:28:11.699354894 +0000 UTC m=+718067.348486606 Received: from herokuapp.com (unknown) by geopod-ismtpd-0 (SG) with ESMTP id S1i3cF90STi6JzgAbVOV4Q for ; Thu, 13 Jun 2024 04:28:11.664 +0000 (UTC) Date: Thu, 13 Jun 2024 04:28:11 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Feature X-Redmine-Issue-Id: 20564 X-Redmine-Issue-Author: kddnewton X-Redmine-Issue-Priority: Normal X-Redmine-Sender: matz 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: 94941 X-SG-EID: =?us-ascii?Q?u001=2Eqca74XLbbBG2T0HhbEZgBN9E1Qhb0c7bGBe1waNAWdTreSqyWPDekZUgq?= =?us-ascii?Q?NYk4+nm=2F0VIqwc8ZBTQxqk7G=2FctsRLtYG2yTl=2FP?= =?us-ascii?Q?2CaGNETxG2T6fcehAsy2PtaTA=2FIGB38FsIvncPw?= =?us-ascii?Q?3NCDifgw66iBGFdHk4J6VJLpLG7V010BdAAXNgm?= =?us-ascii?Q?gRtErehXp8qysn=2FfzLZWlgVLMNHK9WlXwp1wL4F?= =?us-ascii?Q?nrUtGs+TU+QYjRoc+WbSYZBo6lCxnnU0Ielpuai?= =?us-ascii?Q?O7GZ3izmPkXArgc9q7er60WyPw=3D=3D?= To: ruby-core@ml.ruby-lang.org X-Entity-ID: u001.I8uzylDtAfgbeCOeLBYDww== Message-ID-Hash: ZIICZMB4IUUFPYTQKQZACU6LBRXDKVGP X-Message-ID-Hash: ZIICZMB4IUUFPYTQKQZACU6LBRXDKVGP X-MailFrom: bounces+313651-b711-ruby-core=ml.ruby-lang.org@em5188.ruby-lang.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.9 Precedence: list Reply-To: Ruby developers Subject: [ruby-core:118311] [Ruby master Feature#20564] Switch default parser to Prism List-Id: Ruby developers Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: "matz (Yukihiro Matsumoto) via ruby-core" Cc: "matz (Yukihiro Matsumoto)" Issue #20564 has been updated by matz (Yukihiro Matsumoto). Prism needs quality and for that it needs to be experimented with on a wider scale. For that reason, I agree with making Prism the default in previews (when Prism passes all tests). Whether it will eventually become the default in 3.4 depends on quality. Matz. ---------------------------------------- Feature #20564: Switch default parser to Prism https://bugs.ruby-lang.org/issues/20564#change-108819 * Author: kddnewton (Kevin Newton) * Status: Open ---------------------------------------- This issue is to propose switching the default parser for Ruby to Prism on the master branch. The main goal is to get this default into both master and the next preview so that the community has plenty of time to test before the eventual 3.4 release. Matz has indicated that the final decision about the default parser for Ruby 3.4 will be made later in the year. Decisions about the default parser for Ruby 3.5+ and the relationship between Prism, lrama, parse.y, etc. will also be made at a later time. ## Background For some background on the Prism project itself, here are a couple of links in chronological order that you can read: * https://bugs.ruby-lang.org/issues/19741 * https://railsatscale.com/2023-06-12-rewriting-the-ruby-parser/ * https://kddnewton.com/2024/01/23/prism.html * https://railsatscale.com/2024-04-16-prism-in-2024/ ## Status Prism now passes all Ruby tests and specs. Internally at Shopify, it also passes our Core monolith's CI, which is a large and complex Rails application. We are confident that it is ready for production use. External to CRuby, Prism has already been adopted extensively around the ecosystem, including but not limited to: * [JRuby](https://github.com/jruby/jruby/pull/8103) (via Java) * [TruffleRuby](https://github.com/oracle/truffleruby/issues/3117) (via Java) * [Natalie](https://github.com/natalie-lang/natalie/pull/1213) (via C++ and Ruby) * [Opal](https://github.com/opal/opal/pull/2642) (via Ruby and WASM) * [repl_type_completor](https://github.com/ruby/repl_type_completor) * [rubocop](https://docs.rubocop.org/rubocop/configuration.html#setting-the-parser-engine) (via parser translator) * [ruby-lsp](https://github.com/Shopify/ruby-lsp) * [packwerk](https://github.com/Shopify/packwerk/pull/388) (via parser translator) Fortunately with the community adoption, we have been able to find many edge cases and bugs that have been fixed. Thank you so much to everyone who has tried, used, reported problems with, and improved Prism in the last couple of years. We would not have hit this milestone without this community involvement. ## Caveats While Prism correctly accepts and parses all valid Ruby syntax, there are still a number of cases where it does not reject invalid syntax as it should. We are currently working on these cases, and we are confident that we can eliminate them before the next preview release. You can find them listed here: https://github.com/ruby/prism/issues?q=is%3Aopen+is%3Aissue+label%3Ainvalid-syntax. This is our top priority right now, and I anticipate these being resolved quickly. The other caveat is unknown unknowns: bugs or syntax issues that we have yet to discover. At Shopify we are currently taking numerous steps to mitigate this risk, including: * Prism currently passes all Ruby tests and specs, and will continue to going forward. The tests and specs are extensive, and we are confident this gets us almost all of the way there. * Grammar-based fuzzing to ensure we handle all possible syntax variations (both valid and invalid). As an example, that recently led to the discovery that the current compiler was segfaulting on safe navigation in for loops (https://bugs.ruby-lang.org/issues/20468). It has also found several memory leaks that have been fixed. * Mutation testing of existing source files (by adding and deleting random bytes) to find additional edge cases. Our goal is 100% compatibility, and we believe this is achievable through the above techniques and others. The goal of this proposal is to allow more companies to test their codebase against Prism, and to make this easier. We believe that we can sort out the remaining problems much more quickly in that manner. ## Implementation The implementation will be relatively straightforward, as there is already the `--parser` flag that can be used to switch between the current parser and Prism. We will change the default to be `"prism"` instead of `"parse.y"`. There is no plan to remove or change any code related to `parse.y`, `lrama`, or `compile.c` at this time, as we want to create the minimal amount of change possible to ensure stability. -- https://bugs.ruby-lang.org/