Method: NameError#missing_name

Defined in:
lib/active_support/core_ext/name_error.rb

#missing_name ⇒ Object

Extract the name of the missing constant from the exception message.

begin
  HelloWorld
rescue NameError => e
  e.missing_name
end
# => "HelloWorld"



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# File 'lib/active_support/core_ext/name_error.rb', line 12

def missing_name
  # Since ruby v2.3.0 `did_you_mean` gem is loaded by default.
  # It extends NameError#message with spell corrections which are SLOW.
  # We should use original_message message instead.
  message = respond_to?(:original_message) ? original_message : self.message
  return unless message.start_with?("uninitialized constant ")

  receiver = begin
    self.receiver
  rescue ArgumentError
    nil
  end

  if receiver == Object
    name.to_s
  elsif receiver
    "#{real_mod_name(receiver)}::#{self.name}"
  else
    if match = message.match(/((::)?([A-Z]\w*)(::[A-Z]\w*)*)$/)
      match[1]
    end
  end
end