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=-1.8 required=3.0 tests=AWL,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_BL_SPAMCOP_NET,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY shortcircuit=no autolearn=no 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 A87781F5AE for ; Tue, 7 Jul 2020 20:56:50 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 4C700120997; Wed, 8 Jul 2020 05:56:20 +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 645BF120996 for ; Wed, 8 Jul 2020 05:56:18 +0900 (JST) Received: by filterdrecv-p3mdw1-75c584b9c6-qfkhm with SMTP id filterdrecv-p3mdw1-75c584b9c6-qfkhm-21-5F04E189-7D 2020-07-07 20:56:41.884678594 +0000 UTC m=+964029.398125864 Received: from herokuapp.com (unknown) by ismtpd0036p1mdw1.sendgrid.net (SG) with ESMTP id Gh1yo2GXSBmzSIgLOwL3bQ for ; Tue, 07 Jul 2020 20:56:41.810 +0000 (UTC) Date: Tue, 07 Jul 2020 20:56:41 +0000 (UTC) From: bosticko@gmail.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 74872 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Bug X-Redmine-Issue-Id: 17017 X-Redmine-Issue-Author: sambostock X-Redmine-Sender: sambostock 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?=2FfUu9ySTEdIFkNHOx92Y8rGt0ly8q6z7LdBuQfIFYQvSfLvvwhR8O63Bd3fk1f?= =?us-ascii?Q?VDY9KHLMTnKNVWPEmtc6xXgrr9eLjbtw0u9Y48l?= =?us-ascii?Q?DMyKBvkOET7a2neAyCD0zZICLliJK3zunI+CiYZ?= =?us-ascii?Q?4iU2XwrIb2EYPhf96UhmyyQdd=2Fh+TQTDJhiWbqZ?= =?us-ascii?Q?9RHpqj084zrSpXc3OCOwZ3=2FM7GOo54qmHNekwGC?= =?us-ascii?Q?Xo6jLIXg6UrGl3G5I=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 99082 Subject: [ruby-core:99082] [Ruby master Bug#17017] Range#max & Range#minmax incorrectly use Float end as max 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 #17017 has been updated by sambostock (Sam Bostock). Description updated Add documentation change as an option ---------------------------------------- Bug #17017: Range#max & Range#minmax incorrectly use Float end as max https://bugs.ruby-lang.org/issues/17017#change-86453 * Author: sambostock (Sam Bostock) * Status: Open * Priority: Normal * ruby -v: 2.7.1 * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- While continuing to add edge cases to [`Range#minmax` specs](https://github.com/ruby/spec/pull/777), I discovered the following bug: ```ruby (1..3.1).to_a == [1, 2, 3] # As expected (1..3.1).to_a.max == 3 # As expected (1..3.1).to_a.minmax == [1, 3] # As expected (1..3.1).max == 3.1 # Should be 3, as above (1..3.1).minmax == [1, 3.1] # Should be [1, 3], as above ``` One way to detect this scenario might be to do (whatever the C equivalent is of) ```ruby range_end.is_a?(Numeric) // Is this a numeric range? && (range_end - range_begin).modulo(1) == 0 // Can we reach the range_end using the standard step size (1) ``` As for how to handle it, a couple options come to mind: - We could error out and do something similar to what we do for exclusive ranges ```ruby raise TypeError, 'cannot exclude non Integer end value' ``` - We might be able to calculate the range end by doing something like ```ruby num_steps = (range_end / range_beg).to_i - 1 # one fewer steps than would exceed the range_end max = range_beg + num_steps # take that many steps all at once ``` - We could delegate to `super` and enumerate the range to find the max ```ruby super ``` - We could update the documentation to define the max for this case as the `range_end`, similarly to how the documentation for `include?` says it behaves like `cover?` for numeric ranges. -- https://bugs.ruby-lang.org/