Fix encoding crash when LANG environment is empty

[jsxs0]

Description

Fixes encoding crash when LANG= (empty) by using String#scrub to handle invalid characters gracefully.

Problem

When LANG=, debugger crashes with Encoding::CompatibilityError on history files with UTF-8 characters.

Solution

Use String#scrub to clean problematic characters instead of forcing UTF-8 encoding.

Testing

• LANG= ruby -e 'require "debug"; debugger' now works
• Respects system encoding preferences

Fixes #1131

[ko1]

irb seems to handle encoding, but it is not stuck on UTF-8.

ko1@WSL2 ~/ruby/gems/debug
[master]$ irb
irb(main):001> 'あいうえお'
=> "あいうえお"
irb(main):002>

[master]$ tail ~/.irb_history
...
'あいうえお'

[master]$ LANG=C irb
irb(main):001> '???????????????'
=> "???????????????"
irb(main):002>

So I think

• respect LANG at the writing timing (so the patch is too much)
• use String#scrub to prevent hung

seems better.

[jsxs0]

@ko1 Fixed! Using String#scrub now. Thanks!

[ko1]

Thank you!!

[launchable-app]

❌ Tests Failed

✖️no tests failed ✔️74 tests passed(2 flakes)