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 1AAA41F66E for ; Fri, 14 Aug 2020 16:09:17 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id F22B3120A2F; Sat, 15 Aug 2020 01:08:42 +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 4BFBB120A2A for ; Sat, 15 Aug 2020 01:08:41 +0900 (JST) Received: by filterdrecv-p3iad2-5c98798b7-pp5gm with SMTP id filterdrecv-p3iad2-5c98798b7-pp5gm-19-5F36B721-192 2020-08-14 16:09:05.611201215 +0000 UTC m=+85181.491547959 Received: from herokuapp.com (unknown) by geopod-ismtpd-2-0 (SG) with ESMTP id 1ir4D1LBQ7qHyZMrEpQFFg for ; Fri, 14 Aug 2020 16:09:05.550 +0000 (UTC) Date: Fri, 14 Aug 2020 16:09:05 +0000 (UTC) From: daniel@dan42.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 75417 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Bug X-Redmine-Issue-Id: 17017 X-Redmine-Issue-Author: sambostock X-Redmine-Sender: Dan0042 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?8sy4RigFvRTdBfCVJrT9zb2J88PC92TMQwdNgaWYaq7GgW4uj4Q4U4urW4Nsa1?= =?us-ascii?Q?2od6o8uyasglSvElcN8vktc=2FH5ri5jJArg=2FGuvN?= =?us-ascii?Q?h6M1ngBWdWsEKQZOYEDSUMv1xisJ2cB=2FuBsJ=2Fra?= =?us-ascii?Q?usyO95NC+JTMTRUpcKS=2FbbCQg0uSzI=2FIkiq7003?= =?us-ascii?Q?AVQjfhmcnhYFuOH7c72tyZt0sw=2FgT0ejH+fZT2e?= =?us-ascii?Q?bqYIjWk97bln+DHFY=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 99589 Subject: [ruby-core:99589] [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 Dan0042 (Daniel DeLorme). jeremyevans0 (Jeremy Evans) wrote in #note-18: > The behavior change in this issue is to fix an obvious bug, which is that `(1..2.1).max` returned `2.1` instead of `2`. FWIW I consider the previous behavior correct. Intuitively I see `1..2.1` as a float range because one of the ends is a float. And so I expect `(1..2.1).max` to be equivalent to `(1.0..2.1).max` ---------------------------------------- Bug #17017: Range#max & Range#minmax incorrectly use Float end as max https://bugs.ruby-lang.org/issues/17017#change-87066 * Author: sambostock (Sam Bostock) * Status: Closed * Priority: Normal * ruby -v: ruby 2.8.0dev (2020-07-14T04:19:55Z master e60cd14d85) [x86_64-darwin17] * 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/