[ruby-core:111228] [Ruby master Bug#19190] `Regexp.compile('regexp', 'n')` raises `unknown regexp option: n (ArgumentError)`

7 Dec 2022

      Issue #19190 has been reported by koic (Koichi ITO).

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Bug #19190: `Regexp.compile('regexp', 'n')` raises `unknown regexp option: n (ArgumentError)`
https://bugs.ruby-lang.org/issues/19190

* Author: koic (Koichi ITO)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.2.0dev (2022-12-07T03:32:29Z master bcd8b2f00a) [x86_64-darwin19]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
I get the following unexpected error when using Ruby 3.2.0-dev.

## Expected (Ruby 3.1 and prior)

No errors:

```console
% ruby -ve "Regexp.compile('regexp', 'n')"
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-darwin19]
```

## Actual (Ruby 3.2.0-dev)

An unexpected error occurs.

```console
% ruby -ve "Regexp.compile('regexp', 'n')"
ruby 3.2.0dev (2022-12-07T03:32:29Z master bcd8b2f00a) [x86_64-darwin19]
-e:1:in `initialize': unknown regexp option: n (ArgumentError)

Regexp.compile('regexp', 'n')
               ^^^^^^^^^^^^^
        from -e:1:in `compile'
        from -e:1:in `<main>'
```

## Context

I encountered the following error when developing the Parser gem with Ruby 3.2.0-dev. This is not encountered in Ruby 3.1.

```console
% cd whitequark/parser
% bundle exec rake
racc --superclass=Parser::Base lib/parser/ruby32.y -o lib/parser/ruby32.rb --no-line-convert
/Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:219:in `initialize': unknown regexp option: n (ArgumentError)

      Regexp.compile(map, 'n')
                     ^^^^^^^^
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:219:in `compile'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:219:in `mkmapexp'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:179:in `addent'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:122:in `block in gen_action_tables'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/state.rb:56:in `each'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/state.rb:56:in `each_state'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:112:in `gen_action_tables'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:72:in `generate'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/statetransitiontable.rb:35:in `generate'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/state.rb:93:in `state_transition_table'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/grammar.rb:153:in `parser_class'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/grammarfileparser.rb:144:in `<module:Racc>'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/grammarfileparser.rb:20:in `<top (required)>'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/static.rb:3:in `require'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/lib/racc/static.rb:3:in `<top (required)>'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/bin/racc:11:in `require'
        from /Users/koic/.rbenv/versions/3.2.0-dev/lib/ruby/gems/3.2.0+3/gems/racc-1.6.0/bin/racc:11:in `<top (required)>'
        from /Users/koic/.rbenv/versions/3.2.0-dev/bin/racc:25:in `load'
        from /Users/koic/.rbenv/versions/3.2.0-dev/bin/racc:25:in `<main>'
rake aborted!
Command failed with status (1): [racc --superclass=Parser::Base lib/parser/...]
/Users/koic/src/github.com/whitequark/parser/Rakefile:166:in `block in <top (required)>'
/Users/koic/.rbenv/versions/3.2.0-dev/bin/bundle:25:in `load'
/Users/koic/.rbenv/versions/3.2.0-dev/bin/bundle:25:in `<main>'
Tasks: TOP => default => test => generate => lib/parser/ruby32.rb
(See full trace by running task with --trace)
```

-- 
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