From: "headius (Charles Nutter)" <noreply@ruby-lang.org>
To: ruby-core@neon.ruby-lang.org
Subject: [ruby-core:110815] [Ruby master Bug#19113] Inconsistency in retention of compare_by_identity flag in Hash methods
Date: Fri, 18 Nov 2022 18:37:01 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-100173.20221118183700.1604@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-19113.20221109000421.1604@ruby-lang.org
Issue #19113 has been updated by headius (Charles Nutter).
Even though it's a "new Hash", it is supposed to be populated with "the given objects". If losing identity comparison means some keys don't get populated, I would consider that broken.
----------------------------------------
Bug #19113: Inconsistency in retention of compare_by_identity flag in Hash methods
https://bugs.ruby-lang.org/issues/19113#change-100173
* Author: jeremyevans0 (Jeremy Evans)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.2.0dev (2022-11-07T17:29:28Z master 9001e53e68) [x86_64-openbsd7.2]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
`Hash.[]` and `Hash.ruby2_keywords_hash` retain the compare_by_identity flag for non-empty hashes, but do not retain it for empty hashes:
```ruby
hs = [{}.compare_by_identity, {:a=>1}.compare_by_identity]
hs.map{|h| Hash[h].compare_by_identity?}
# => [false, true]
hs.map{|h| Hash.ruby2_keywords_hash(h).compare_by_identity?}
# => [false, true]
```
This inconsistency seems like a bug.
`Hash#compact` always drops the compare_by_identity flag, but it is documented as returning a copy of self, implying the compare_by_identity flag is kept (since #dup and #clone retain the flag).
```ruby
{}.compare_by_identity.compact.compare_by_identity?
# => false
```
I'm not sure whether is a bug, because it is consistent, but I think retaining the flag makes more sense.
I'll try to work on a fix for both of these issues tomorrow.
--
https://bugs.ruby-lang.org/
next prev parent reply other threads:[~2022-11-18 18:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 0:04 [ruby-core:110663] [Ruby master Bug#19113] Inconsistency in retention of compare_by_identity flag in Hash methods jeremyevans0 (Jeremy Evans)
2022-11-09 20:21 ` [ruby-core:110672] " jeremyevans0 (Jeremy Evans)
2022-11-15 7:38 ` [ruby-core:110759] " ko1 (Koichi Sasada)
2022-11-18 17:03 ` [ruby-core:110812] " headius (Charles Nutter)
2022-11-18 17:03 ` [ruby-core:110813] " headius (Charles Nutter)
2022-11-18 17:32 ` [ruby-core:110814] " jeremyevans0 (Jeremy Evans)
2022-11-18 18:37 ` headius (Charles Nutter) [this message]
2022-11-18 18:57 ` [ruby-core:110816] " jeremyevans0 (Jeremy Evans)
2022-11-18 19:47 ` [ruby-core:110817] " Eregon (Benoit Daloze)
2022-12-23 2:39 ` [ruby-core:111389] " matz (Yukihiro Matsumoto) via ruby-core
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