End of Life Ruby 3.1 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

OptionParser::ParseError#reason

reason

# File tmp/rubies/ruby-3.1.3/lib/optparse.rb, line 2063
def reason
  @reason || self.class::Reason
end

Returns error reason. Override this for I18N.

See also #message #recover #inspect #set_backtrace also in 3.3 · 3.2 · 3.0