Refactor using Forwardable and DelegateClass.

Library/Homebrew/cask/lib/hbc/artifact/base.rb

@@ -1,6 +1,8 @@
 module Hbc
   module Artifact
     class Base
+      extend Predicable
+
       def self.artifact_name
         @artifact_name ||= name.sub(/^.*:/, "").gsub(/(.)([A-Z])/, '\1_\2').downcase
       end
@@ -65,13 +67,7 @@ module Hbc
         {}
       end
 
-      def verbose?
-        @verbose
-      end
-
-      def force?
-        @force
-      end
+      attr_predicate :force?, :verbose?
 
       def initialize(cask, command: SystemCommand, force: false, verbose: false)
         @cask = cask

Library/Homebrew/cask/lib/hbc/cask.rb

@@ -1,5 +1,3 @@
-require "forwardable"
-
 require "hbc/dsl"
 require "hbc/metadata"
 

Library/Homebrew/cask/lib/hbc/checkable.rb

@@ -1,29 +1,27 @@
 module Hbc
   module Checkable
     def errors
-      Array(@errors)
+      @errors ||= []
     end
 
     def warnings
-      Array(@warnings)
+      @warnings ||= []
     end
 
     def add_error(message)
-      @errors ||= []
-      @errors << message
+      errors << message
     end
 
     def add_warning(message)
-      @warnings ||= []
-      @warnings << message
+      warnings << message
     end
 
     def errors?
-      Array(@errors).any?
+      errors.any?
     end
 
     def warnings?
-      Array(@warnings).any?
+      warnings.any?
     end
 
     def result

Library/Homebrew/cask/lib/hbc/installer.rb

@@ -6,6 +6,7 @@ require "hbc/verify"
 
 module Hbc
   class Installer
+    extend Predicable
     # TODO: it is unwise for Hbc::Staged to be a module, when we are
     #       dealing with both staged and unstaged Casks here. This should
     #       either be a class which is only sometimes instantiated, or there
@@ -27,21 +28,7 @@ module Hbc
       @reinstall = false
     end
 
-    def skip_cask_deps?
-      @skip_cask_deps
-    end
-
-    def force?
-      @force
-    end
-
-    def binaries?
-      @binaries
-    end
-
-    def verbose?
-      @verbose
-    end
+    attr_predicate :binaries?, :force?, :skip_cask_deps?, :require_sha?, :verbose?
 
     def self.print_caveats(cask)
       odebug "Printing caveats"
@@ -75,7 +62,7 @@ module Hbc
       odebug "Hbc::Installer#fetch"
 
       satisfy_dependencies
-      verify_has_sha if @require_sha && !force?
+      verify_has_sha if require_sha? && !force?
       download
       verify
     end

Library/Homebrew/cask/lib/hbc/url.rb

@@ -1,5 +1,3 @@
-require "forwardable"
-
 module Hbc
   class URL
     FAKE_USER_AGENT = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10) https://caskroom.github.io".freeze

Library/Homebrew/cask/lib/hbc/utils.rb

@@ -14,14 +14,14 @@ class Object
 end
 
 class Buffer < StringIO
+  extend Predicable
+
+  attr_predicate :tty?
+
   def initialize(tty = false)
     super()
     @tty = tty
   end
-
-  def tty?
-    @tty
-  end
 end
 
 # global methods

Library/Homebrew/caveats.rb

@@ -1,4 +1,6 @@
 class Caveats
+  extend Forwardable
+
   attr_reader :f
 
   def initialize(f)
@@ -25,9 +27,7 @@ class Caveats
     caveats.compact.join("\n")
   end
 
-  def empty?
-    caveats.empty?
-  end
+  delegate [:empty?, :to_s] => :caveats
 
   private
 

Library/Homebrew/checksum.rb

@@ -1,6 +1,7 @@
 class Checksum
+  extend Forwardable
+
   attr_reader :hash_type, :hexdigest
-  alias to_s hexdigest
 
   TYPES = [:sha256].freeze
 
@@ -9,9 +10,7 @@ class Checksum
     @hexdigest = hexdigest
   end
 
-  def empty?
-    hexdigest.empty?
-  end
+  delegate [:empty?, :to_s] => :@hexdigest
 
   def ==(other)
     hash_type == other.hash_type && hexdigest == other.hexdigest

Library/Homebrew/cmd/info.rb

@@ -169,8 +169,8 @@ module Homebrew
       Homebrew.dump_options_for_formula f
     end
 
-    c = Caveats.new(f)
-    ohai "Caveats", c.caveats unless c.empty?
+    caveats = Caveats.new(f)
+    ohai "Caveats", caveats.to_s unless caveats.empty?
   end
 
   def decorate_dependencies(dependencies)

Library/Homebrew/cmd/update-report.rb

@@ -547,6 +547,8 @@ class Reporter
 end
 
 class ReporterHub
+  extend Forwardable
+
   attr_reader :reporters
 
   def initialize
@@ -564,9 +566,7 @@ class ReporterHub
     @hash.update(report) { |_key, oldval, newval| oldval.concat(newval) }
   end
 
-  def empty?
-    @hash.empty?
-  end
+  delegate :empty? => :@hash
 
   def dump
     # Key Legend: Added (A), Copied (C), Deleted (D), Modified (M), Renamed (R)

Library/Homebrew/debrew.rb

@@ -74,18 +74,13 @@ module Debrew
     end
   end
 
-  class << self
-    alias original_raise raise
-  end
-
   @active = false
   @debugged_exceptions = Set.new
 
-  def self.active?
-    @active
-  end
-
   class << self
+    extend Predicable
+    alias original_raise raise
+    attr_predicate :active?
     attr_reader :debugged_exceptions
   end
 

Library/Homebrew/dependencies.rb

@@ -1,28 +1,11 @@
-class Dependencies
-  include Enumerable
+require "delegate"
 
-  def initialize
-    @deps = []
+class Dependencies < DelegateClass(Array)
+  def initialize(*args)
+    super(args)
   end
 
-  def each(*args, &block)
-    @deps.each(*args, &block)
-  end
-
-  def <<(o)
-    @deps << o
-    self
-  end
-
-  def empty?
-    @deps.empty?
-  end
-
-  def *(arg)
-    @deps * arg
-  end
-
-  alias to_ary to_a
+  alias eql? ==
 
   def optional
     select(&:optional?)
@@ -44,40 +27,28 @@ class Dependencies
     build + required + recommended
   end
 
-  attr_reader :deps
-  protected :deps
-
-  def ==(other)
-    deps == other.deps
-  end
-  alias eql? ==
-
   def inspect
-    "#<#{self.class.name}: #{to_a.inspect}>"
+    "#<#{self.class.name}: #{to_a}>"
   end
 end
 
-class Requirements
-  include Enumerable
-
-  def initialize
-    @reqs = Set.new
-  end
-
-  def each(*args, &block)
-    @reqs.each(*args, &block)
+class Requirements < DelegateClass(Set)
+  def initialize(*args)
+    super(Set.new(args))
   end
 
   def <<(other)
     if other.is_a?(Comparable)
-      @reqs.grep(other.class) do |req|
+      grep(other.class) do |req|
         return self if req > other
-        @reqs.delete(req)
+        delete(req)
       end
     end
-    @reqs << other
+    super
     self
   end
 
-  alias to_ary to_a
+  def inspect
+    "#<#{self.class.name}: {#{to_a.join(", ")}}>"
+  end
 end

Library/Homebrew/dependency.rb

@@ -2,6 +2,7 @@ require "dependable"
 
 # A dependency on another Homebrew formula.
 class Dependency
+  extend Forwardable
   include Dependable
 
   attr_reader :name, :tags, :env_proc, :option_names
@@ -34,9 +35,7 @@ class Dependency
     formula
   end
 
-  def installed?
-    to_formula.installed?
-  end
+  delegate installed?: :to_formula
 
   def satisfied?(inherited_options)
     installed? && missing_options(inherited_options).empty?

Library/Homebrew/download_strategy.rb

@@ -3,6 +3,7 @@ require "rexml/document"
 require "time"
 
 class AbstractDownloadStrategy
+  extend Forwardable
   include FileUtils
 
   attr_reader :meta, :name, :version, :resource
@@ -181,9 +182,7 @@ class VCSDownloadStrategy < AbstractDownloadStrategy
     @clone
   end
 
-  def head?
-    version.head?
-  end
+  delegate head?: :version
 
   # Return last commit's unique identifier for the repository.
   # Return most recent modified timestamp unless overridden.

Library/Homebrew/extend/predicable.rb

@@ -0,0 +1,9 @@
+module Predicable
+  def attr_predicate(*attrs)
+    attrs.each do |attr|
+      define_method attr do
+        instance_variable_get("@#{attr.to_s.sub(/\?$/, "")}") == true
+      end
+    end
+  end
+end

Library/Homebrew/formula.rb

@@ -45,6 +45,7 @@ class Formula
   include Utils::Inreplace
   include Utils::Shell
   extend Enumerable
+  extend Forwardable
 
   # @!method inreplace(paths, before = nil, after = nil)
   # Actually implemented in {Utils::Inreplace.inreplace}.
@@ -314,37 +315,14 @@ class Formula
     active_spec == head
   end
 
-  # @private
-  def bottle_unneeded?
-    active_spec.bottle_unneeded?
-  end
-
-  # @private
-  def bottle_disabled?
-    active_spec.bottle_disabled?
-  end
-
-  # @private
-  def bottle_disable_reason
-    active_spec.bottle_disable_reason
-  end
-
-  # Does the currently active {SoftwareSpec} have any bottle?
-  # @private
-  def bottle_defined?
-    active_spec.bottle_defined?
-  end
-
-  # Does the currently active {SoftwareSpec} have an installable bottle?
-  # @private
-  def bottled?
-    active_spec.bottled?
-  end
-
-  # @private
-  def bottle_specification
-    active_spec.bottle_specification
-  end
+  delegate [
+    :bottle_unneeded?,
+    :bottle_disabled?,
+    :bottle_disable_reason,
+    :bottle_defined?,
+    :bottled?,
+    :bottle_specification,
+  ] => :active_spec
 
   # The Bottle object for the currently active {SoftwareSpec}.
   # @private
@@ -353,24 +331,21 @@ class Formula
   end
 
   # The description of the software.
+  # @method desc
   # @see .desc
-  def desc
-    self.class.desc
-  end
+  delegate desc: :"self.class"
 
   # The homepage for the software.
+  # @method homepage
   # @see .homepage
-  def homepage
-    self.class.homepage
-  end
+  delegate homepage: :"self.class"
 
   # The version for the currently active {SoftwareSpec}.
   # The version is autodetected from the URL and/or tag so only needs to be
   # declared if it cannot be autodetected correctly.
+  # @method version
   # @see .version
-  def version
-    active_spec.version
-  end
+  delegate version: :active_spec
 
   def update_head_version
     return unless head?
@@ -394,9 +369,8 @@ class Formula
   # Additional downloads can be defined as {#resource}s.
   # {Resource#stage} will create a temporary directory and yield to a block.
   # <pre>resource("additional_files").stage { bin.install "my/extra/tool" }</pre>
-  def resource(name)
-    active_spec.resource(name)
-  end
+  # @method resource
+  delegate resource: :active_spec
 
   # An old name for the formula
   def oldname
@@ -416,68 +390,39 @@ class Formula
   end
 
   # The {Resource}s for the currently active {SoftwareSpec}.
-  def resources
-    active_spec.resources.values
-  end
+  # @method resources
+  def_delegator :"active_spec.resources", :values, :resources
 
   # The {Dependency}s for the currently active {SoftwareSpec}.
-  # @private
-  def deps
-    active_spec.deps
-  end
+  delegate deps: :active_spec
 
   # The {Requirement}s for the currently active {SoftwareSpec}.
-  # @private
-  def requirements
-    active_spec.requirements
-  end
+  delegate requirements: :active_spec
 
   # The cached download for the currently active {SoftwareSpec}.
-  # @private
-  def cached_download
-    active_spec.cached_download
-  end
+  delegate cached_download: :active_spec
 
   # Deletes the download for the currently active {SoftwareSpec}.
-  # @private
-  def clear_cache
-    active_spec.clear_cache
-  end
+  delegate clear_cache: :active_spec
 
   # The list of patches for the currently active {SoftwareSpec}.
-  # @private
-  def patchlist
-    active_spec.patches
-  end
+  def_delegator :active_spec, :patches, :patchlist
 
   # The options for the currently active {SoftwareSpec}.
-  # @private
-  def options
-    active_spec.options
-  end
+  delegate options: :active_spec
 
   # The deprecated options for the currently active {SoftwareSpec}.
-  # @private
-  def deprecated_options
-    active_spec.deprecated_options
-  end
+  delegate deprecated_options: :active_spec
 
   # The deprecated option flags for the currently active {SoftwareSpec}.
-  # @private
-  def deprecated_flags
-    active_spec.deprecated_flags
-  end
+  delegate deprecated_flags: :active_spec
 
   # If a named option is defined for the currently active {SoftwareSpec}.
-  def option_defined?(name)
-    active_spec.option_defined?(name)
-  end
+  # @method option_defined?
+  delegate option_defined?: :active_spec
 
   # All the {.fails_with} for the currently active {SoftwareSpec}.
-  # @private
-  def compiler_failures
-    active_spec.compiler_failures
-  end
+  delegate compiler_failures: :active_spec
 
   # If this {Formula} is installed.
   # This is actually just a check for if the {#installed_prefix} directory

Library/Homebrew/formula_installer.rb

@@ -17,6 +17,7 @@ require "development_tools"
 
 class FormulaInstaller
   include FormulaCellarChecks
+  extend Predicable
 
   def self.mode_attr_accessor(*names)
     attr_accessor(*names)
@@ -559,11 +560,11 @@ class FormulaInstaller
 
     audit_installed if ARGV.homebrew_developer? && !formula.keg_only?
 
-    c = Caveats.new(formula)
+    caveats = Caveats.new(formula)
 
-    return if c.empty?
+    return if caveats.empty?
     @show_summary_heading = true
-    ohai "Caveats", c.caveats
+    ohai "Caveats", caveats.to_s
   end
 
   def finish
@@ -879,9 +880,7 @@ class FormulaInstaller
 
   private
 
-  def hold_locks?
-    @hold_locks || false
-  end
+  attr_predicate :hold_locks?
 
   def lock
     return unless (@@locked ||= []).empty?

Library/Homebrew/formula_support.rb

@@ -81,7 +81,7 @@ class BottleDisableReason
   end
 
   def to_s
-    if @type == :unneeded
+    if unneeded?
       "This formula doesn't require compiling."
     else
       @reason

Library/Homebrew/global.rb

@@ -1,4 +1,6 @@
+require "forwardable"
 require "extend/module"
+require "extend/predicable"
 require "extend/fileutils"
 require "extend/pathname"
 require "extend/git_repository"

Library/Homebrew/resource.rb

@@ -1,7 +1,6 @@
 require "download_strategy"
 require "checksum"
 require "version"
-require "forwardable"
 
 # Resource is the fundamental representation of an external resource. The
 # primary formula download, along with other declared resources, are instances

Library/Homebrew/software_spec.rb

@@ -1,4 +1,3 @@
-require "forwardable"
 require "resource"
 require "checksum"
 require "version"