Promote did_you_mean to default gem

At the moment, there are some problems with regard to bundler + did_you_mean because of did_you_mean being a bundled gem. Since the vendored version of thor inside bundler and ruby itself explicitly requires did_you_mean, it can become difficult to load it when using Bundler.setup. See this issue: ruby/did_you_mean#117 (comment) for more details.

doc/maintainers.rdoc

@@ -162,6 +162,9 @@ Zachary Scott (zzak)
   _unmaintained_
   https://github.com/ruby/delegate
   https://rubygems.org/gems/delegate
+[lib/did_you_mean.rb]
+  Yuki Nishijima (yuki24)
+  https://github.com/ruby/did_you_mean
 [lib/fileutils.rb]
   _unmaintained_
   https://github.com/ruby/fileutils
@@ -342,8 +345,6 @@ Zachary Scott (zzak)
 
 == Bundled gems upstream repositories
 
-[did_you_mean]
-  https://github.com/yuki24/did_you_mean
 [minitest]
   https://github.com/seattlerb/minitest
 [net-telnet]

doc/standard_library.rdoc

@@ -62,6 +62,7 @@ Bundler:: Manage your Ruby application's gem dependencies
 CGI:: Support for the Common Gateway Interface protocol
 CSV:: Provides an interface to read and write CSV files and data
 Delegator:: Provides three abilities to delegate method calls to an object
+DidYouMean:: "Did you mean?" experience in Ruby
 FileUtils:: Several file utility methods for copying, moving, removing, etc
 Forwardable:: Provides delegation of specified methods to a designated object
 GetoptLong:: Parse command line options similar to the GNU C getopt_long()
@@ -112,7 +113,6 @@ Zlib:: Ruby interface for the zlib compression/decompression library
 
 == Libraries
 
-DidYouMean:: "Did you mean?" experience in Ruby
 MiniTest:: A test suite with TDD, BDD, mocking and benchmarking
 Net::Telnet:: Telnet client library for Ruby
 PowerAssert:: Power Assert for Ruby.

gems/bundled_gems

@@ -1,4 +1,3 @@
-did_you_mean 1.3.1 https://github.com/yuki24/did_you_mean
 minitest 5.13.0 https://github.com/seattlerb/minitest
 net-telnet 0.2.0 https://github.com/ruby/net-telnet
 power_assert 1.1.5 https://github.com/k-tsj/power_assert

lib/did_you_mean.rb

@@ -0,0 +1,110 @@
+require_relative "did_you_mean/version"
+require_relative "did_you_mean/core_ext/name_error"
+
+require_relative "did_you_mean/spell_checker"
+require_relative 'did_you_mean/spell_checkers/name_error_checkers'
+require_relative 'did_you_mean/spell_checkers/method_name_checker'
+require_relative 'did_you_mean/spell_checkers/key_error_checker'
+require_relative 'did_you_mean/spell_checkers/null_checker'
+require_relative 'did_you_mean/formatters/plain_formatter'
+require_relative 'did_you_mean/tree_spell_checker'
+
+# 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)
+#
+module DidYouMean
+  # Map of error types and spell checker objects.
+  SPELL_CHECKERS = Hash.new(NullChecker)
+
+  # Adds +DidYouMean+ functionality to an error using a given spell checker
+  def self.correct_error(error_class, spell_checker)
+    SPELL_CHECKERS[error_class.name] = spell_checker
+    error_class.prepend(Correctable) unless error_class < Correctable
+  end
+
+  correct_error NameError, NameErrorCheckers
+  correct_error KeyError, KeyErrorChecker
+  correct_error NoMethodError, MethodNameChecker
+
+  # Returns the currenctly set formatter. By default, it is set to +DidYouMean::Formatter+.
+  def self.formatter
+    @@formatter
+  end
+
+  # Updates the primary formatter used to format the suggestions.
+  def self.formatter=(formatter)
+    @@formatter = formatter
+  end
+
+  self.formatter = PlainFormatter.new
+end

lib/did_you_mean/core_ext/name_error.rb

@@ -0,0 +1,25 @@
+module DidYouMean
+  module Correctable
+    def original_message
+      method(:to_s).super_method.call
+    end
+
+    def to_s
+      msg = super.dup
+      suggestion = DidYouMean.formatter.message_for(corrections)
+
+      msg << suggestion if !msg.end_with?(suggestion)
+      msg
+    rescue
+      super
+    end
+
+    def corrections
+      @corrections ||= spell_checker.corrections
+    end
+
+    def spell_checker
+      SPELL_CHECKERS[self.class.to_s].new(self)
+    end
+  end
+end

lib/did_you_mean/did_you_mean.gemspec

@@ -0,0 +1,23 @@
+# coding: utf-8
+lib = File.expand_path('../lib', __FILE__)
+$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
+require 'did_you_mean/version'
+
+Gem::Specification.new do |spec|
+  spec.name          = "did_you_mean"
+  spec.version       = DidYouMean::VERSION
+  spec.authors       = ["Yuki Nishijima"]
+  spec.email         = ["[email protected]"]
+  spec.summary       = '"Did you mean?" experience in Ruby'
+  spec.description   = 'The gem that has been saving people from typos since 2014.'
+  spec.homepage      = "https://github.com/ruby/did_you_mean"
+  spec.license       = "MIT"
+
+  spec.files         = `git ls-files`.split($/).reject{|path| path.start_with?('evaluation/') }
+  spec.test_files    = spec.files.grep(%r{^(test)/})
+  spec.require_paths = ["lib"]
+
+  spec.required_ruby_version = '>= 2.5.0'
+
+  spec.add_development_dependency "rake"
+end

lib/did_you_mean/experimental.rb

@@ -0,0 +1,2 @@
+warn "Experimental features in the did_you_mean gem has been removed " \
+     "and `require \"did_you_mean/experimental\"' has no effect."

lib/did_you_mean/experimental/initializer_name_correction.rb

@@ -0,0 +1,20 @@
+# frozen-string-literal: true
+
+require_relative '../levenshtein'
+
+module DidYouMean
+  module Experimental
+    module InitializerNameCorrection
+      def method_added(name)
+        super
+
+        distance = Levenshtein.distance(name.to_s, 'initialize')
+        if distance != 0 && distance <= 2
+          warn "warning: #{name} might be misspelled, perhaps you meant initialize?"
+        end
+      end
+    end
+
+    ::Class.prepend(InitializerNameCorrection)
+  end
+end

lib/did_you_mean/experimental/ivar_name_correction.rb

@@ -0,0 +1,76 @@
+# frozen-string-literal: true
+
+require_relative '../../did_you_mean'
+
+module DidYouMean
+  module Experimental #:nodoc:
+    class IvarNameCheckerBuilder #:nodoc:
+      attr_reader :original_checker
+
+      def initialize(original_checker) #:nodoc:
+        @original_checker = original_checker
+      end
+
+      def new(no_method_error) #:nodoc:
+        IvarNameChecker.new(no_method_error, original_checker: @original_checker)
+      end
+    end
+
+    class IvarNameChecker #:nodoc:
+      REPLS = {
+        "(irb)" => -> { Readline::HISTORY.to_a.last }
+      }
+
+      TRACE = TracePoint.trace(:raise) do |tp|
+        e = tp.raised_exception
+
+        if SPELL_CHECKERS.include?(e.class.to_s) && !e.instance_variable_defined?(:@frame_binding)
+          e.instance_variable_set(:@frame_binding, tp.binding)
+        end
+      end
+
+      attr_reader :original_checker
+
+      def initialize(no_method_error, original_checker: )
+        @original_checker = original_checker.new(no_method_error)
+
+        @location   = no_method_error.backtrace_locations.first
+        @ivar_names = no_method_error.frame_binding.receiver.instance_variables
+
+        no_method_error.remove_instance_variable(:@frame_binding)
+      end
+
+      def corrections
+        original_checker.corrections + ivar_name_corrections
+      end
+
+      def ivar_name_corrections
+        @ivar_name_corrections ||= SpellChecker.new(dictionary: @ivar_names).correct(receiver_name.to_s)
+      end
+
+      private
+
+      def receiver_name
+        return unless @original_checker.receiver.nil?
+
+        abs_path = @location.absolute_path
+        lineno   = @location.lineno
+
+        /@(\w+)*\.#{@original_checker.method_name}/ =~ line(abs_path, lineno).to_s && $1
+      end
+
+      def line(abs_path, lineno)
+        if REPLS[abs_path]
+          REPLS[abs_path].call
+        elsif File.exist?(abs_path)
+          File.open(abs_path) do |file|
+            file.detect { file.lineno == lineno }
+          end
+        end
+      end
+    end
+  end
+
+  NameError.send(:attr, :frame_binding)
+  SPELL_CHECKERS['NoMethodError'] = Experimental::IvarNameCheckerBuilder.new(SPELL_CHECKERS['NoMethodError'])
+end

lib/did_you_mean/formatters/plain_formatter.rb

@@ -0,0 +1,33 @@
+# frozen-string-literal: true
+
+module DidYouMean
+  # The +DidYouMean::PlainFormatter+ is the basic, default formatter for the
+  # gem. The formatter responds to the +message_for+ method and it returns a
+  # human readable string.
+  class PlainFormatter
+
+    # Returns a human readable string that contains +corrections+. This
+    # formatter is designed to be less verbose to not take too much screen
+    # space while being helpful enough to the user.
+    #
+    # @example
+    #
+    #   formatter = DidYouMean::PlainFormatter.new
+    #
+    #   # displays suggestions in two lines with the leading empty line
+    #   puts formatter.message_for(["methods", "method"])
+    #
+    #   Did you mean?  methods
+    #                   method
+    #   # => nil
+    #
+    #   # displays an empty line
+    #   puts formatter.message_for([])
+    #
+    #   # => nil
+    #
+    def message_for(corrections)
+      corrections.empty? ? "" : "\nDid you mean?  #{corrections.join("\n               ")}"
+    end
+  end
+end

lib/did_you_mean/formatters/verbose_formatter.rb

@@ -0,0 +1,49 @@
+# frozen-string-literal: true
+
+module DidYouMean
+  # The +DidYouMean::VerboseFormatter+ uses extra empty lines to make the
+  # suggestion stand out more in the error message.
+  #
+  # In order to activate the verbose formatter,
+  #
+  # @example
+  #
+  #   OBject
+  #   # => NameError: uninitialized constant OBject
+  #   #    Did you mean?  Object
+  #
+  #   require 'did_you_mean/verbose'
+  #
+  #   OBject
+  #   # => NameError: uninitialized constant OBject
+  #   #
+  #   #        Did you mean? Object
+  #   #
+  #
+  class VerboseFormatter
+
+    # Returns a human readable string that contains +corrections+. This
+    # formatter is designed to be less verbose to not take too much screen
+    # space while being helpful enough to the user.
+    #
+    # @example
+    #
+    #   formatter = DidYouMean::PlainFormatter.new
+    #
+    #   puts formatter.message_for(["methods", "method"])
+    #
+    #
+    #       Did you mean? methods
+    #                     method
+    #
+    #   # => nil
+    #
+    def message_for(corrections)
+      return "" if corrections.empty?
+
+      output = "\n\n    Did you mean? ".dup
+      output << corrections.join("\n                  ")
+      output << "\n "
+    end
+  end
+end