Completion crashes on a method having invalid name as UTF-8

[pocke]

Description

IRB crashes with the following code:

irb(main):001> define_method("a\xff".force_encoding(Encoding::ASCII_8BIT)){}
=> :"a\xFF"
irb(main):002> a/Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb/completion.rb:184:in `encode': "\xFF" from ASCII-8BIT to UTF-8 (Encoding::UndefinedConversionError)
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb/completion.rb:184:in `block in completion_candidates'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb/completion.rb:184:in `map'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb/completion.rb:184:in `completion_candidates'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb/input-method.rb:251:in `block in initialize'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:1634:in `call_completion_proc_with_checking_args'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:533:in `call_completion_proc_with_checking_args'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:237:in `block in <class:Core>'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:588:in `instance_exec'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:588:in `call'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:623:in `call'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:776:in `update_each_dialog'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:652:in `block in render_dialog'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:650:in `map'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:650:in `render_dialog'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/line_editor.rb:500:in `rerender'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:351:in `block (3 levels) in inner_readline'
	from <internal:array>:52:in `each'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:349:in `block (2 levels) in inner_readline'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:424:in `block in read_io'
	from <internal:kernel>:191:in `loop'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:394:in `read_io'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:347:in `block in inner_readline'
	from <internal:kernel>:191:in `loop'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:345:in `inner_readline'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:273:in `block in readmultiline'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/ansi.rb:152:in `block in with_raw_input'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/ansi.rb:152:in `raw'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline/ansi.rb:152:in `with_raw_input'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/reline.rb:269:in `readmultiline'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/3.4.0+0/forwardable.rb:240:in `readmultiline'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb/input-method.rb:453:in `gets'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:1028:in `block in read_input'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:1316:in `signal_status'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:1026:in `read_input'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:1048:in `readmultiline'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:1075:in `block in each_top_level_statement'
	from <internal:kernel>:191:in `loop'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:1074:in `each_top_level_statement'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:996:in `eval_input'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:983:in `block in run'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:982:in `catch'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:982:in `run'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/lib/irb.rb:884:in `start'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/lib/ruby/gems/3.4.0+0/gems/irb-1.11.2/exe/irb:9:in `<top (required)>'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/bin/irb:25:in `load'
	from /Users/kuwabara.masataka/.rbenv/versions/trunk/bin/irb:25:in `<main>'

Note that IRB crashes when I enter a to the second IRB prompt.

Result of irb_info

Please paste the result of irb_info command in IRB.

ex.)

irb(main):001> irb_info
Ruby version: 3.4.0
IRB version: irb 1.11.2 (2024-02-07)
InputMethod: RelineInputMethod with Reline 0.4.2
Completion: Autocomplete, RegexpCompletor
RUBY_PLATFORM: arm64-darwin21
East Asian Ambiguous Width: 1

Terminal Emulator

Terminal.app of macOS

Setting Files

No irbrc. I removed ~/.irbrc before testing it.

---

BTW, I encountered this problem on the HEAD of ruby/ruby, and also Ruby 3.1.

I think it is an extremely rare case because no one has defined a method with an invalid name as UTF-8, but I reported it just in case.