[ruby-core:126343] [Ruby Bug#20958] fix ENV.keys encoding on windows

9 Aug 2026


      Issue #20958 has been updated by nagachika (Tomoyuki Chikanaga).

Backport changed from 3.3: WONTFIX, 3.4: REQUIRED, 4.0: REQUIRED to 3.3: WONTFIX, 3.4: DONE, 4.0: REQUIRED

ruby_3_4 commit:d784a0b8a5c1f9ca59f95779c6a07eb7c69e223d merged revision(s) commit:239a472609db43bf8a5388c4c8da11b1a4b322f6, commit:d29afc8ab801ab3d32fcd787e43fbae7ea2630a6.

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Bug #20958: fix ENV.keys encoding on windows
https://bugs.ruby-lang.org/issues/20958#change-118460

* Author: YO4 (Yoshinao Muramatsu)
* Status: Closed
* Assignee: windows
* Backport: 3.3: WONTFIX, 3.4: DONE, 4.0: REQUIRED
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[github PR#12368](https://github.com/ruby/ruby/pull/12368)
ENV.keys elements contain UTF-8 byte sequences with locale encoding on Windows.
```
...
ruby -v -e "p ENV.keys.last; p ENV.keys.last.encoding; p ENV.keys.last.dup.force_encoding('utf-8')"
ruby 3.3.5 (2024-09-03 revision ef084cc8f4) [x64-mingw-ucrt]
"\x{E383}\x{86E3}\x{82B9}\x{E383}\x88"
#<Encoding:Windows-31J>
"テスト"
This patch changes the encoding of ENV.keys to utf-8 on Windows.


-- 
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