The DidYouMean gem adds functionality to suggest possible method/class names upon errors such as NameError and NoMethodError. In Ruby 2.3 or later, it is automatically activated during startup.
@example
methosd # => NameError: undefined local variable or method `methosd' for main:Object # Did you mean? methods # method OBject # => NameError: uninitialized constant OBject # Did you mean? Object @full_name = "Yuki Nishijima" first_name, last_name = full_name.split(" ") # => NameError: undefined local variable or method `full_name' for main:Object # Did you mean? @full_name @@full_name = "Yuki Nishijima" @@full_anme # => NameError: uninitialized class variable @@full_anme in Object # Did you mean? @@full_name full_name = "Yuki Nishijima" full_name.starts_with?("Y") # => NoMethodError: undefined method `starts_with?' for "Yuki Nishijima":String # Did you mean? start_with? hash = {foo: 1, bar: 2, baz: 3} hash.fetch(:fooo) # => KeyError: key not found: :fooo # Did you mean? :foo
Disabling did_you_mean
Occasionally, you may want to disable the did_you_mean gem for e.g. debugging issues in the error object itself. You can disable it entirely by specifying --disable-did_you_mean option to the ruby command:
$ ruby --disable-did_you_mean -e "1.zeor?" -e:1:in `<main>': undefined method `zeor?' for 1:Integer (NameError)
When you do not have direct access to the ruby command (e.g. +rails console+, irb), you could applyoptions using the RUBYOPT environment variable:
$ RUBYOPT='--disable-did_you_mean' irb irb:0> 1.zeor? # => NoMethodError (undefined method `zeor?' for 1:Integer)
Getting the original error message
Sometimes, you do not want to disable the gem entirely, but need to get the original error message without suggestions (e.g. testing). In this case, you could use the #original_message method on the error object:
no_method_error = begin 1.zeor? rescue NoMethodError => error error end no_method_error.message # => NoMethodError (undefined method `zeor?' for 1:Integer) # Did you mean? zero? no_method_error.original_message # => NoMethodError (undefined method `zeor?' for 1:Integer)
TODO: Remove on the 3.4 development start:
The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.
The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.
# File tmp/rubies/ruby-master/lib/did_you_mean.rb, line 97
def self.correct_error(error_class, spell_checker)
if defined?(Ractor)
new_mapping = { **@spell_checkers, error_class.to_s => spell_checker }
new_mapping.default = NullChecker
@spell_checkers = Ractor.make_shareable(new_mapping)
else
spell_checkers[error_class.to_s] = spell_checker
end
error_class.prepend(Correctable) if error_class.is_a?(Class) && !(error_class < Correctable)
end
Adds DidYouMean functionality to an error using a given spell checker
# File tmp/rubies/ruby-master/lib/did_you_mean.rb, line 141
def self.formatter
if defined?(Ractor)
Ractor.current[:__did_you_mean_formatter__] || Formatter
else
Formatter
end
end
Returns the currently set formatter. By default, it is set to DidYouMean::Formatter.
# File tmp/rubies/ruby-master/lib/did_you_mean.rb, line 150
def self.formatter=(formatter)
if defined?(Ractor)
Ractor.current[:__did_you_mean_formatter__] = formatter
end
end
Updates the primary formatter used to format the suggestions.
# File tmp/rubies/ruby-master/lib/did_you_mean.rb, line 92
def self.spell_checkers
@spell_checkers
end
Returns a sharable hash map of error types and spell checker objects.