[ruby-core:104464] [Ruby master Bug#17757] Hash#slice does not keep compare_by_identity on the results
From:
marcandre-ruby-core@...
Date:
2021-07-01 20:16:46 UTC
List:
ruby-core #104464
Issue #17757 has been updated by marcandre (Marc-Andre Lafortune).
Thanks for the PR @jeremyevans0, looks pretty good.
On the other hand, I'd like to revise what I wrote and suggest that `transform_keys` remain untouched. It's the only one of these methods that changes the keys so has a reason to interpret them differently.
Matz, do you agree?
----------------------------------------
Bug #17757: Hash#slice does not keep compare_by_identity on the results
https://bugs.ruby-lang.org/issues/17757#change-92720
* Author: kachick (Kenichi Kamiya)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
GH-PR: https://github.com/ruby/ruby/pull/4330
```console
$ ruby -v
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]
```
```ruby
str1 = +'str'
str2 = +'str'
hash = {a: :a, b: :b, c: :c}.compare_by_identity
hash[str1] = 1
hash[str2] = 2
p hash.values_at(str1, str2) #=> [1, 2]
p hash.except.compare_by_identity? #=> true
p hash.slice.compare_by_identity? #=> false
p hash.except(str1, str2) #=> {:a=>:a, :b=>:b, :c=>:c}
p hash.slice(str1, str2) #=> {"str"=>2}
```
Is this an intentional behavior?
I would expect Hash#slice keeps compare_by_identity behaviors.
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