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=-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,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 716EF1F66E for ; Fri, 14 Aug 2020 17:54:18 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 31EEA120A77; Sat, 15 Aug 2020 02:53:43 +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 CAA15120A2D for ; Sat, 15 Aug 2020 02:53:40 +0900 (JST) Received: by filterdrecv-p3iad2-5c98798b7-xhpjb with SMTP id filterdrecv-p3iad2-5c98798b7-xhpjb-20-5F36CFBE-65 2020-08-14 17:54:06.725262789 +0000 UTC m=+91477.472059666 Received: from herokuapp.com (unknown) by ismtpd0092p1mdw1.sendgrid.net (SG) with ESMTP id IMCcjM8SQza4M434G6a70A for ; Fri, 14 Aug 2020 17:54:06.610 +0000 (UTC) Date: Fri, 14 Aug 2020 17:54:06 +0000 (UTC) From: merch-redmine@jeremyevans.net Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 75418 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Bug X-Redmine-Issue-Id: 17017 X-Redmine-Issue-Author: sambostock X-Redmine-Sender: jeremyevans0 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?RVE3t853K5scBhbmJHUzZTFFeVC=2FZSUmHZ0Dc+26wcEi2CTgsF1oz0wTSSxGGN?= =?us-ascii?Q?BI1sZojqAq6l15bSyeyJGxUhbXKD+zjNkm57Xhi?= =?us-ascii?Q?rwNCtHpodZ6b7ry0FfL6ES6wlTiEfX7UytNopEq?= =?us-ascii?Q?2=2FX=2FyeO8M+avLeEaO1Cgbw1TNoayKrMDU27gQyj?= =?us-ascii?Q?6bcagg5Pay1RjYNbuwd8p5+yaUa90X3aMogPEnf?= =?us-ascii?Q?iAOQEdBElV=2FNmgtl4=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 99590 Subject: [ruby-core:99590] [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 jeremyevans0 (Jeremy Evans). Dan0042 (Daniel DeLorme) wrote in #note-22: > 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` `integer..float` is currently treated as a integer range in all other respects. For example: ```ruby (1.0..2.1).to_a # TypeError (can't iterate from Float) (1..2.1).to_a # => [1, 2] ``` So if we want to treat `integer..float` to be a float range, it will require changes far beyond `#max` and `#minmax`. I think this is a fix for a bug/regression introduced in Ruby 1.9 due to an improper optimization: ``` $ ruby18 -ve 'p((1..2.1).max)' ruby 1.8.7 (2013-06-27 patchlevel 374) [x86_64-openbsd] 2 $ ruby19 -ve 'p((1..2.1).max)' ruby 1.9.3p551 (2014-11-13 revision 48407) [x86_64-openbsd] 2.1 ``` ---------------------------------------- Bug #17017: Range#max & Range#minmax incorrectly use Float end as max https://bugs.ruby-lang.org/issues/17017#change-87067 * 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/