From: "sawa (Tsuyoshi Sawada)" <noreply@...>
Date: 2022-10-24T05:42:38+00:00
Subject: [ruby-core:110494] [Ruby master Bug#19080] String Range inclusion using `===` broken

Issue #19080 has been updated by sawa (Tsuyoshi Sawada).


You need to zero-pad the strings in order to compare them correctly by the number they express. It is and advanced thing, and people without appropriate knowledge would/should not try doing it.

----------------------------------------
Bug #19080: String Range inclusion using `===` broken
https://bugs.ruby-lang.org/issues/19080#change-99815

* Author: baweaver (Brandon Weaver)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.0
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
When using `===` implicitly for a pattern match I noticed a behavior which I believe is a bug in Ruby. `===` does not match with `include?` for ranges of `String` types, but also does so inconsistently:

```ruby
range = '0'..'255'

('1'..'5').map do |v|
  {
    v: v,
    teq: range === v,
    include?: range.include?(v)
  }
end
#  => [
#   { v: "1", teq: true, include?: true },
#   { v: "2", teq: true, include?: true },
#   { v: "3", teq: false, include?: true },
#   { v: "4", teq: false, include?: true },
#   { v: "5", teq: false, include?: true }
# ]

# But numbers work??
range = 0..255

(1..5).map do |v|
  {
    v: v,
    teq: range === v,
    include?: range.include?(v)
  }
end
# => [
#   { v: 1, teq: true, include?: true},
#   { v: 2, teq: true, include?: true},
#   { v: 3, teq: true, include?: true},
#   { v: 4, teq: true, include?: true},
#   { v: 5, teq: true, include?: true}
# ]
```

Am I doing something wrong? This does not feel like it is working as expected. I might dig through the C code to see how this is implemented and why this happens, but am currently confused by it.



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