From: "wanabe (_ wanabe) via ruby-core" <ruby-core@...>
Date: 2026-08-16T08:11:55+00:00
Subject: [ruby-core:126401] [Ruby Bug#11808] Different behavior between Enumerable#grep and Array#grep

Issue #11808 has been updated by wanabe (_ wanabe).

Status changed from Assigned to Closed

It has been fixed at 0a82bfe5e18ac86da72c27389db6eb8da156a0b5  == https://github.com/ruby/ruby/pull/7225

```
$ cat a.rb
class Test
  include Enumerable
  def each
    return enum_for(:each) unless block_given?
    yield "Hello"
    yield "World"
  end
end

enum = Test.new
array = ["Hello", "World"]

p enum.grep(/^(.)/) {$1}
p array.grep(/^(.)/) {$1}

$ git checkout 0a82bfe5e18ac86da72c27389db6eb8da156a0b5~ && make -j miniruby > /dev/null 2>&1 && ./miniruby a.rb
HEAD is now at 2675f2c864f Remove whitespace
[nil, nil]
["H", "W"]
$ git checkout 0a82bfe5e18ac86da72c27389db6eb8da156a0b5 && make -j miniruby > /dev/null 2>&1 && ./miniruby a.rb
Previous HEAD position was 2675f2c864f Remove whitespace
HEAD is now at 0a82bfe5e18 use correct svar (#7225)
["H", "W"]
["H", "W"]
```
This commit is included in 3.3.
Since 3.2 is end-of-life, there is no need to backport it.

----------------------------------------
Bug #11808: Different behavior between Enumerable#grep and Array#grep
https://bugs.ruby-lang.org/issues/11808#change-118539

* Author: BenOlive (Ben Olive)
* Status: Closed
* Assignee: ko1 (Koichi Sasada)
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
Regex special global variables are available within the block for `Array#grep`, but are nil within the block for `Enumerable#grep`.

Here is an example that explains it better:

~~~ruby
class Test
  include Enumerable
  def each
    return enum_for(:each) unless block_given?
    yield "Hello"
    yield "World"
  end
end

enum = Test.new
array = ["Hello", "World"]

enum.grep(/^(.)/) {$1} # => [nil, nil]
array.grep(/^(.)/) {$1} # => ["H", "W"]
~~~

Tested on 2.0.0, 2.1.5, & 2.2.2



-- 
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