Clean up code style and remove `.rubocop_todo.yml`.

44 files changed, 295 insertions, 420 deletions

diff --git a/Library/Homebrew/.rubocop.yml b/Library/Homebrew/.rubocop.yml
index 3b440c33c..143468643 100644
--- a/Library/Homebrew/.rubocop.yml
+++ b/Library/Homebrew/.rubocop.yml
@@ -1,6 +1,5 @@
 inherit_from:
   - ../.rubocop.yml
-  - .rubocop_todo.yml
 
 AllCops:
   Include:
@@ -26,9 +25,26 @@ Lint/NestedMethodDefinition:
 Lint/ParenthesesAsGroupedExpression:
   Enabled: true
 
+Metrics/BlockNesting:
+  Max: 5
+
+Metrics/ModuleLength:
+  Max: 360
+
 Metrics/ParameterLists:
   CountKeywordArgs: false
 
+# we won't change backward compatible method names
+Naming/MethodName:
+  Exclude:
+    - 'compat/**/*'
+
+# we won't change backward compatible predicate names
+Naming/PredicateName:
+  Exclude:
+    - 'compat/**/*'
+  NameWhitelist: is_32_bit?, is_64_bit?
+
 Style/BlockDelimiters:
   Exclude:
     - '**/*_spec.rb'
@@ -41,14 +57,3 @@ Style/GuardClause:
 # hash-rockets preferred for formulae, a: 1 preferred elsewhere
 Style/HashSyntax:
   EnforcedStyle: ruby19_no_mixed_keys
-
-# we won't change backward compatible method names
-Naming/MethodName:
-  Exclude:
-    - 'compat/**/*'
-
-# we won't change backward compatible predicate names
-Naming/PredicateName:
-  Exclude:
-    - 'compat/**/*'
-  NameWhitelist: is_32_bit?, is_64_bit?
diff --git a/Library/Homebrew/.rubocop_todo.yml b/Library/Homebrew/.rubocop_todo.yml
deleted file mode 100644
index 96c2f3676..000000000
--- a/Library/Homebrew/.rubocop_todo.yml
+++ /dev/null
@@ -1,138 +0,0 @@
-# This configuration was generated by
-# `rubocop --auto-gen-config --exclude-limit 100`
-# on 2017-01-27 21:44:55 +0000 using RuboCop version 0.47.1.
-# The point is for the user to remove these configuration records
-# one by one as the offenses are removed from the code base.
-# Note that changes in the inspected code, or installation of new
-# versions of RuboCop, may require this file to be generated again.
-
-# Offense count: 17
-Lint/HandleExceptions:
-  Exclude:
-    - 'cmd/install.rb'
-    - 'cmd/reinstall.rb'
-    - 'cmd/tap.rb'
-    - 'cmd/update-report.rb'
-    - 'cmd/upgrade.rb'
-    - 'cmd/uses.rb'
-    - 'descriptions.rb'
-    - 'diagnostic.rb'
-    - 'extend/ENV/super.rb'
-    - 'extend/pathname.rb'
-    - 'formula.rb'
-    - 'formula_versions.rb'
-    - 'test/ENV_test.rb'
-
-# Offense count: 3
-Lint/IneffectiveAccessModifier:
-  Exclude:
-    - 'formula.rb'
-    - 'version.rb'
-
-# Offense count: 1
-Lint/Loop:
-  Exclude:
-    - 'patch.rb'
-
-# Offense count: 28
-Lint/RescueException:
-  Exclude:
-    - 'brew.rb'
-    - 'build.rb'
-    - 'cmd/fetch.rb'
-    - 'cmd/reinstall.rb'
-    - 'cmd/update-report.rb'
-    - 'debrew.rb'
-    - 'dev-cmd/pull.rb'
-    - 'dev-cmd/test.rb'
-    - 'formula.rb'
-    - 'formula_installer.rb'
-    - 'migrator.rb'
-    - 'postinstall.rb'
-    - 'readall.rb'
-    - 'test.rb'
-    - 'test/ENV_test.rb'
-    - 'utils/fork.rb'
-
-# Offense count: 1
-Lint/ShadowedException:
-  Exclude:
-    - 'utils/fork.rb'
-
-# Offense count: 13
-# Configuration parameters: CountBlocks.
-Metrics/BlockNesting:
-  Max: 5
-
-# Offense count: 19
-# Configuration parameters: CountComments.
-Metrics/ModuleLength:
-  Max: 400
-
-# Offense count: 1
-# Configuration parameters: CountKeywordArgs.
-Metrics/ParameterLists:
-  Max: 6
-
-# Offense count: 2
-Security/MarshalLoad:
-  Exclude:
-    - 'dependency.rb'
-    - 'utils/fork.rb'
-
-# Offense count: 1
-Naming/AccessorMethodName:
-  Exclude:
-    - 'extend/ENV/super.rb'
-
-# Offense count: 6
-Style/ClassVars:
-  Exclude:
-    - 'dev-cmd/audit.rb'
-    - 'formula_installer.rb'
-    - 'test/support/helper/fs_leak_logger.rb'
-
-# Offense count: 13
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle, SupportedStyles.
-# SupportedStyles: compact, expanded
-Style/EmptyMethod:
-  Exclude:
-    - 'debrew/irb.rb'
-    - 'download_strategy.rb'
-    - 'extend/ENV/super.rb'
-    - 'formula.rb'
-    - 'patch.rb'
-
-# Offense count: 13
-# Configuration parameters: AllowedVariables.
-Style/GlobalVars:
-  Exclude:
-    - 'diagnostic.rb'
-    - 'utils.rb'
-
-# Offense count: 1
-# Configuration parameters: EnforcedStyle, SupportedStyles.
-# SupportedStyles: module_function, extend_self
-Style/ModuleFunction:
-  Exclude:
-    - 'os/mac/xcode.rb'
-
-# Offense count: 8
-Style/MultilineBlockChain:
-  Exclude:
-    - 'cmd/search.rb'
-    - 'dev-cmd/aspell-dictionaries.rb'
-    - 'dev-cmd/audit.rb'
-    - 'dev-cmd/man.rb'
-    - 'diagnostic.rb'
-    - 'test/patching_test.rb'
-
-# Offense count: 4
-# Cop supports --auto-correct.
-Style/MutableConstant:
-  Exclude:
-    - 'dependency_collector.rb'
-    - 'formulary.rb'
-    - 'tab.rb'
-    - 'tap.rb'
diff --git a/Library/Homebrew/brew.rb b/Library/Homebrew/brew.rb
index 41955e60e..86b40a79d 100644
--- a/Library/Homebrew/brew.rb
+++ b/Library/Homebrew/brew.rb
@@ -146,7 +146,7 @@ rescue MethodDeprecatedError => e
     $stderr.puts "  #{Formatter.url(e.issues_url)}"
   end
   exit 1
-rescue Exception => e
+rescue Exception => e # rubocop:disable Lint/RescueException
   onoe e
   if internal_cmd && defined?(OS::ISSUES_URL) &&
      !ENV["HOMEBREW_NO_AUTO_UPDATE"]
diff --git a/Library/Homebrew/build.rb b/Library/Homebrew/build.rb
index cd2fa4c02..836b360da 100644
--- a/Library/Homebrew/build.rb
+++ b/Library/Homebrew/build.rb
@@ -190,7 +190,7 @@ begin
   options = Options.create(ARGV.flags_only)
   build   = Build.new(formula, options)
   build.install
-rescue Exception => e
+rescue Exception => e # rubocop:disable Lint/RescueException
   Marshal.dump(e, error_pipe)
   error_pipe.close
   exit! 1
diff --git a/Library/Homebrew/cmd/fetch.rb b/Library/Homebrew/cmd/fetch.rb
index 006c63746..411753992 100644
--- a/Library/Homebrew/cmd/fetch.rb
+++ b/Library/Homebrew/cmd/fetch.rb
@@ -49,8 +49,10 @@ module Homebrew
       if fetch_bottle?(f)
         begin
           fetch_formula(f.bottle)
-        rescue Exception => e
-          raise if ARGV.homebrew_developer? || e.is_a?(Interrupt)
+        rescue Interrupt
+          raise
+        rescue => e
+          raise if ARGV.homebrew_developer?
           fetched_bottle = false
           onoe e.message
           opoo "Bottle fetch failed: fetching the source."
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index 732e96b00..ca8f29477 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -339,6 +339,7 @@ module Homebrew
   rescue FormulaInstallationAlreadyAttemptedError
     # We already attempted to install f as part of the dependency tree of
     # another formula. In that case, don't generate an error, just move on.
+    return
   rescue CannotInstallFormulaError => e
     ofail e.message
   end
diff --git a/Library/Homebrew/cmd/reinstall.rb b/Library/Homebrew/cmd/reinstall.rb
index 94096d2dd..6727c0b6b 100644
--- a/Library/Homebrew/cmd/reinstall.rb
+++ b/Library/Homebrew/cmd/reinstall.rb
@@ -47,8 +47,8 @@ module Homebrew
     fi.install
     fi.finish
   rescue FormulaInstallationAlreadyAttemptedError
-    # next
-  rescue Exception
+    return
+  rescue Exception # rubocop:disable Lint/RescueException
     ignore_interrupts { restore_backup(keg, keg_was_linked) }
     raise
   else
diff --git a/Library/Homebrew/cmd/style.rb b/Library/Homebrew/cmd/style.rb
index e816db5dc..58f430a27 100644
--- a/Library/Homebrew/cmd/style.rb
+++ b/Library/Homebrew/cmd/style.rb
@@ -117,6 +117,7 @@ module Homebrew
 
     case output_type
     when :print
+      args << "--debug" if ARGV.debug?
       args << "--display-cop-names" if ARGV.include? "--display-cop-names"
       args << "--format" << "simple" if files
       system(cache_env, "rubocop", "_#{HOMEBREW_RUBOCOP_VERSION}_", *args)
diff --git a/Library/Homebrew/cmd/tap.rb b/Library/Homebrew/cmd/tap.rb
index 2a07c1b2f..fa520e2c5 100644
--- a/Library/Homebrew/cmd/tap.rb
+++ b/Library/Homebrew/cmd/tap.rb
@@ -54,8 +54,7 @@ module Homebrew
                     quiet: ARGV.quieter?
       rescue TapRemoteMismatchError => e
         odie e
-      rescue TapAlreadyTappedError, TapAlreadyUnshallowError
-        # Do nothing.
+      rescue TapAlreadyTappedError, TapAlreadyUnshallowError # rubocop:disable Lint/HandleExceptions
       end
     end
   end
diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 781ee8808..0974df0b4 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -372,7 +372,7 @@ class Reporter
           new_version = formula.pkg_version
           old_version = FormulaVersions.new(formula).formula_at_revision(@initial_revision, &:pkg_version)
           next if new_version == old_version
-        rescue Exception => e
+        rescue Exception => e # rubocop:disable Lint/RescueException
           onoe "#{e.message}\n#{e.backtrace.join "\n"}" if ARGV.homebrew_developer?
         end
         @report[:M] << tap.formula_file_to_name(src)
@@ -460,7 +460,7 @@ class Reporter
           unless Formulary.factory(new_full_name).keg_only?
             system HOMEBREW_BREW_FILE, "link", new_full_name, "--overwrite"
           end
-        rescue Exception => e
+        rescue Exception => e # rubocop:disable Lint/RescueException
           onoe "#{e.message}\n#{e.backtrace.join "\n"}" if ARGV.homebrew_developer?
         end
         next
@@ -521,7 +521,7 @@ class Reporter
 
       begin
         f = Formulary.factory(new_full_name)
-      rescue Exception => e
+      rescue Exception => e # rubocop:disable Lint/RescueException
         onoe "#{e.message}\n#{e.backtrace.join "\n"}" if ARGV.homebrew_developer?
         next
       end
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index 1cdb497cf..f1ce3c7da 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -150,6 +150,7 @@ module Homebrew
   rescue FormulaInstallationAlreadyAttemptedError
     # We already attempted to upgrade f as part of the dependency tree of
     # another formula. In that case, don't generate an error, just move on.
+    return
   rescue CannotInstallFormulaError => e
     ofail e
   rescue BuildError => e
diff --git a/Library/Homebrew/cmd/uses.rb b/Library/Homebrew/cmd/uses.rb
index 24684c3b6..0b09e1bf1 100644
--- a/Library/Homebrew/cmd/uses.rb
+++ b/Library/Homebrew/cmd/uses.rb
@@ -74,12 +74,13 @@ module Homebrew
               end
             end
 
-            dep_formulae = deps.map do |dep|
+            dep_formulae = deps.flat_map do |dep|
               begin
                 dep.to_formula
               rescue
+                []
               end
-            end.compact
+            end
 
             reqs_by_formula = ([f] + dep_formulae).flat_map do |formula|
               formula.requirements.map { |req| [formula, req] }
@@ -118,6 +119,7 @@ module Homebrew
         rescue FormulaUnavailableError
           # Silently ignore this case as we don't care about things used in
           # taps that aren't currently tapped.
+          next
         end
       end
     end
diff --git a/Library/Homebrew/debrew.rb b/Library/Homebrew/debrew.rb
index 5bc3d2daa..6206eb8a2 100644
--- a/Library/Homebrew/debrew.rb
+++ b/Library/Homebrew/debrew.rb
@@ -9,7 +9,7 @@ module Debrew
   module Raise
     def raise(*)
       super
-    rescue Exception => e
+    rescue Exception => e # rubocop:disable Lint/RescueException
       e.extend(Ignorable)
       super(e) unless Debrew.debug(e) == :ignore
     end
@@ -92,7 +92,7 @@ module Debrew
       yield
     rescue SystemExit
       original_raise
-    rescue Exception => e
+    rescue Exception => e # rubocop:disable Lint/RescueException
       debug(e)
     ensure
       @active = false
@@ -119,7 +119,7 @@ module Debrew
           if e.is_a?(Ignorable)
             menu.choice(:irb) do
               puts "When you exit this IRB session, execution will continue."
-              set_trace_func proc { |event, _, _, id, binding, klass|
+              set_trace_func proc { |event, _, _, id, binding, klass| # rubocop:disable Metrics/ParameterLists
                 if klass == Raise && id == :raise && event == "return"
                   set_trace_func(nil)
                   synchronize { IRB.start_within(binding) }
diff --git a/Library/Homebrew/debrew/irb.rb b/Library/Homebrew/debrew/irb.rb
index 069dbe676..eeb3758a9 100644
--- a/Library/Homebrew/debrew/irb.rb
+++ b/Library/Homebrew/debrew/irb.rb
@@ -4,8 +4,7 @@ module IRB
   @setup_done = false
 
   extend Module.new {
-    def parse_opts
-    end
+    def parse_opts; end
 
     def start_within(binding)
       unless @setup_done
diff --git a/Library/Homebrew/dependency.rb b/Library/Homebrew/dependency.rb
index 0fbc2625b..7f0e7fbff 100644
--- a/Library/Homebrew/dependency.rb
+++ b/Library/Homebrew/dependency.rb
@@ -64,7 +64,7 @@ class Dependency
   end
 
   def self._load(marshaled)
-    new(*Marshal.load(marshaled))
+    new(*Marshal.load(marshaled)) # rubocop:disable Security/MarshalLoad
   end
 
   class << self
diff --git a/Library/Homebrew/dependency_collector.rb b/Library/Homebrew/dependency_collector.rb
index fff80a28c..f855669e0 100644
--- a/Library/Homebrew/dependency_collector.rb
+++ b/Library/Homebrew/dependency_collector.rb
@@ -4,6 +4,7 @@ require "ld64_dependency"
 require "requirement"
 require "requirements"
 require "set"
+require "extend/cachable"
 
 ## A dependency is a formula that another formula needs to install.
 ## A requirement is something other than a formula that another formula
@@ -16,17 +17,13 @@ require "set"
 # This class is used by `depends_on` in the formula DSL to turn dependency
 # specifications into the proper kinds of dependencies and requirements.
 class DependencyCollector
+  extend Cachable
+
   # Define the languages that we can handle as external dependencies.
   LANGUAGE_MODULES = Set[
     :lua, :lua51, :perl, :python, :python3, :ruby
   ].freeze
 
-  CACHE = {}
-
-  def self.clear_cache
-    CACHE.clear
-  end
-
   attr_reader :deps, :requirements
 
   def initialize
@@ -45,7 +42,7 @@ class DependencyCollector
   end
 
   def fetch(spec)
-    CACHE.fetch(cache_key(spec)) { |key| CACHE[key] = build(spec) }
+    self.class.cache.fetch(cache_key(spec)) { |key| self.class.cache[key] = build(spec) }
   end
 
   def cache_key(spec)
diff --git a/Library/Homebrew/descriptions.rb b/Library/Homebrew/descriptions.rb
index ac1d68216..bc1982673 100644
--- a/Library/Homebrew/descriptions.rb
+++ b/Library/Homebrew/descriptions.rb
@@ -78,10 +78,10 @@ class Descriptions
 
     formula_names.each do |name|
       begin
-        desc = Formulary.factory(name).desc
+        @cache[name] = Formulary.factory(name).desc
       rescue FormulaUnavailableError, *FormulaVersions::IGNORED_EXCEPTIONS
+        @cache.delete(name)
       end
-      @cache[name] = desc
     end
     save_cache if options[:save]
   end
diff --git a/Library/Homebrew/dev-cmd/aspell-dictionaries.rb b/Library/Homebrew/dev-cmd/aspell-dictionaries.rb
index 955e41b01..ab0e66d2b 100644
--- a/Library/Homebrew/dev-cmd/aspell-dictionaries.rb
+++ b/Library/Homebrew/dev-cmd/aspell-dictionaries.rb
@@ -27,13 +27,12 @@ module Homebrew
       end
     end
 
-    languages.inject([]) do |resources, (lang, path)|
+    languages.each do |lang, path|
       r = Resource.new(lang)
       r.owner = Formulary.factory("aspell")
       r.url "#{dict_url}/#{path}"
       r.mirror "#{dict_mirror}/#{path}"
-      resources << r
-    end.each(&:fetch).each do |r|
+      r.fetch
       puts <<-EOS
         option "with-lang-#{r.name}", "Install #{r.name} dictionary"
         resource "#{r.name}" do
diff --git a/Library/Homebrew/dev-cmd/audit.rb b/Library/Homebrew/dev-cmd/audit.rb
index 16ae7cba1..6afd1f802 100644
--- a/Library/Homebrew/dev-cmd/audit.rb
+++ b/Library/Homebrew/dev-cmd/audit.rb
@@ -53,7 +53,7 @@ module Homebrew
   module_function
 
   def audit
-    Homebrew.inject_dump_stats!(FormulaAuditor, /^audit_/) if ARGV.switch? "D"
+    inject_dump_stats!(FormulaAuditor, /^audit_/) if ARGV.switch? "D"
     Homebrew.auditing = true
 
     formula_count = 0
@@ -387,8 +387,10 @@ class FormulaAuditor
     end
   end
 
-  # core aliases + tap alias names + tap alias full name
-  @@aliases ||= Formula.aliases + Formula.tap_aliases
+  def self.aliases
+    # core aliases + tap alias names + tap alias full name
+    @aliases ||= Formula.aliases + Formula.tap_aliases
+  end
 
   def audit_formula_name
     return unless @strict
@@ -442,7 +444,7 @@ class FormulaAuditor
           problem "Dependency '#{dep.name}' was renamed; use new name '#{dep_f.name}'."
         end
 
-        if @@aliases.include?(dep.name) &&
+        if self.class.aliases.include?(dep.name) &&
            (dep_f.core_formula? || !dep_f.versioned_formula?)
           problem "Dependency '#{dep.name}' is an alias; use the canonical name '#{dep.to_formula.full_name}'."
         end
@@ -453,16 +455,16 @@ class FormulaAuditor
           problem "Dependency '#{dep.name}' may be unnecessary as it is provided by macOS; try to build this formula without it."
         end
 
-        dep.options.reject do |opt|
-          next true if dep_f.option_defined?(opt)
-          dep_f.requirements.detect do |r|
+        dep.options.each do |opt|
+          next if dep_f.option_defined?(opt)
+          next if dep_f.requirements.detect do |r|
             if r.recommended?
               opt.name == "with-#{r.name}"
             elsif r.optional?
               opt.name == "without-#{r.name}"
             end
           end
-        end.each do |opt|
+
           problem "Dependency #{dep} does not define option #{opt.name.inspect}"
         end
 
diff --git a/Library/Homebrew/dev-cmd/bottle.rb b/Library/Homebrew/dev-cmd/bottle.rb
index 8dfd0d12c..fb862c773 100644
--- a/Library/Homebrew/dev-cmd/bottle.rb
+++ b/Library/Homebrew/dev-cmd/bottle.rb
@@ -75,7 +75,7 @@ module Homebrew
 
       @put_filenames ||= []
 
-      return if @put_filenames.include? filename
+      return if @put_filenames.include?(filename)
 
       puts Formatter.error(filename.to_s)
       @put_filenames << filename
@@ -84,8 +84,7 @@ module Homebrew
     result = false
 
     keg.each_unique_file_matching(string) do |file|
-      # skip document file.
-      next if Metafiles::EXTENSIONS.include? file.extname
+      next if Metafiles::EXTENSIONS.include?(file.extname) # Skip document files.
 
       linked_libraries = Keg.file_linked_libraries(file, string)
       result ||= !linked_libraries.empty?
@@ -156,9 +155,7 @@ module Homebrew
       return ofail "Formula not installed or up-to-date: #{f.full_name}"
     end
 
-    tap = f.tap
-
-    unless tap
+    unless tap = f.tap
       unless ARGV.include?("--force-core-tap")
         return ofail "Formula not from core or any taps: #{f.full_name}"
       end
diff --git a/Library/Homebrew/dev-cmd/man.rb b/Library/Homebrew/dev-cmd/man.rb
index 472bb7c2b..b2bb3c8c3 100644
--- a/Library/Homebrew/dev-cmd/man.rb
+++ b/Library/Homebrew/dev-cmd/man.rb
@@ -48,12 +48,9 @@ module Homebrew
   def path_glob_commands(glob)
     Pathname.glob(glob)
             .sort_by { |source_file| sort_key_for_path(source_file) }
-            .map do |source_file|
-      source_file.read.lines
-                 .grep(/^#:/)
-                 .map { |line| line.slice(2..-1) }
-                 .join
-    end.reject { |s| s.strip.empty? || s.include?("@hide_from_man_page") }
+            .map(&:read).map(&:lines)
+            .map { |lines| lines.grep(/^#:/).map { |line| line.slice(2..-1) }.join }
+            .reject { |s| s.strip.empty? || s.include?("@hide_from_man_page") }
   end
 
   def build_man_page
diff --git a/Library/Homebrew/dev-cmd/pull.rb b/Library/Homebrew/dev-cmd/pull.rb
index cd0d6fbd0..8cb270303 100644
--- a/Library/Homebrew/dev-cmd/pull.rb
+++ b/Library/Homebrew/dev-cmd/pull.rb
@@ -154,8 +154,8 @@ module Homebrew
 
         begin
           f = Formula[name]
-        # Make sure we catch syntax errors.
-        rescue Exception
+        rescue Exception # rubocop:disable Lint/RescueException
+          # Make sure we catch syntax errors.
           next
         end
 
diff --git a/Library/Homebrew/dev-cmd/test.rb b/Library/Homebrew/dev-cmd/test.rb
index ab2b0edb0..6622a8c25 100644
--- a/Library/Homebrew/dev-cmd/test.rb
+++ b/Library/Homebrew/dev-cmd/test.rb
@@ -84,7 +84,7 @@ module Homebrew
       rescue ::Test::Unit::AssertionFailedError => e
         ofail "#{f.full_name}: failed"
         puts e.message
-      rescue Exception => e
+      rescue Exception => e # rubocop:disable Lint/RescueException
         ofail "#{f.full_name}: failed"
         puts e, e.backtrace
       ensure
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 88aa4dbc9..3edf31012 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -151,8 +151,10 @@ module Homebrew
         return unless File.directory?(dir)
 
         files = Dir.chdir(dir) do
-          Dir[pattern].select { |f| File.file?(f) && !File.symlink?(f) } - Dir.glob(white_list)
-        end.map { |file| File.join(dir, file) }
+          (Dir.glob(pattern) - Dir.glob(white_list))
+            .select { |f| File.file?(f) && !File.symlink?(f) }
+            .map { |f| File.join(dir, f) }
+        end
         return if files.empty?
 
         inject_file_list(files, message)
@@ -427,15 +429,15 @@ module Homebrew
       end
 
       def check_user_path_1
-        $seen_prefix_bin = false
-        $seen_prefix_sbin = false
+        @seen_prefix_bin = false
+        @seen_prefix_sbin = false
 
         message = ""
 
         paths(ENV["HOMEBREW_PATH"]).each do |p|
           case p
           when "/usr/bin"
-            unless $seen_prefix_bin
+            unless @seen_prefix_bin
               # only show the doctor message if there are any conflicts
               # rationale: a default install should not trigger any brew doctor messages
               conflicts = Dir["#{HOMEBREW_PREFIX}/bin/*"]
@@ -458,9 +460,9 @@ module Homebrew
               end
             end
           when "#{HOMEBREW_PREFIX}/bin"
-            $seen_prefix_bin = true
+            @seen_prefix_bin = true
           when "#{HOMEBREW_PREFIX}/sbin"
-            $seen_prefix_sbin = true
+            @seen_prefix_sbin = true
           end
         end
 
@@ -468,7 +470,7 @@ module Homebrew
       end
 
       def check_user_path_2
-        return if $seen_prefix_bin
+        return if @seen_prefix_bin
 
         <<-EOS.undent
           Homebrew's bin was not found in your PATH.
@@ -478,7 +480,7 @@ module Homebrew
       end
 
       def check_user_path_3
-        return if $seen_prefix_sbin
+        return if @seen_prefix_sbin
 
         # Don't complain about sbin not being in the path if it doesn't exist
         sbin = HOMEBREW_PREFIX/"sbin"
@@ -952,6 +954,7 @@ module Homebrew
           Putting non-prefixed coreutils in your path can cause gmp builds to fail.
         EOS
       rescue FormulaUnavailableError
+        return
       end
 
       def check_for_non_prefixed_findutils
@@ -966,6 +969,7 @@ module Homebrew
           Putting non-prefixed findutils in your path can cause python builds to fail.
         EOS
       rescue FormulaUnavailableError
+        return
       end
 
       def check_for_pydistutils_cfg_in_home
diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 7012fccc8..e69a56ddf 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -18,8 +18,7 @@ class AbstractDownloadStrategy
   end
 
   # Download and cache the resource as {#cached_location}.
-  def fetch
-  end
+  def fetch; end
 
   # Suppress output
   def shutup!
@@ -37,13 +36,11 @@ class AbstractDownloadStrategy
   # Unpack {#cached_location} into the current working directory, and possibly
   # chdir into the newly-unpacked directory.
   # Unlike {Resource#stage}, this does not take a block.
-  def stage
-  end
+  def stage; end
 
   # @!attribute [r] cached_location
   # The path to the cached file or directory associated with the resource.
-  def cached_location
-  end
+  def cached_location; end
 
   # @!attribute [r]
   # return most recent modified time for all files in the current working directory after stage.
@@ -204,14 +201,11 @@ class VCSDownloadStrategy < AbstractDownloadStrategy
     true
   end
 
-  def clone_repo
-  end
+  def clone_repo; end
 
-  def update
-  end
+  def update; end
 
-  def current_revision
-  end
+  def current_revision; end
 
   def extract_ref(specs)
     key = REF_TYPES.find { |type| specs.key?(type) }
diff --git a/Library/Homebrew/extend/ENV/super.rb b/Library/Homebrew/extend/ENV/super.rb
index b518c22a1..b4f0dfcac 100644
--- a/Library/Homebrew/extend/ENV/super.rb
+++ b/Library/Homebrew/extend/ENV/super.rb
@@ -24,8 +24,7 @@ module Superenv
   end
 
   # @private
-  def self.bin
-  end
+  def self.bin; end
 
   def reset
     super
@@ -324,11 +323,9 @@ module Superenv
     end
   end
 
-  def set_x11_env_if_installed
-  end
+  def set_x11_env_if_installed; end
 
-  def set_cpu_flags(*)
-  end
+  def set_cpu_flags(_, _ = "", _ = {}); end
 end
 
 require "extend/os/extend/ENV/super"
diff --git a/Library/Homebrew/extend/cachable.rb b/Library/Homebrew/extend/cachable.rb
new file mode 100644
index 000000000..69d86ccb7
--- /dev/null
+++ b/Library/Homebrew/extend/cachable.rb
@@ -0,0 +1,9 @@
+module Cachable
+  def cache
+    @cache ||= {}
+  end
+
+  def clear_cache
+    cache.clear
+  end
+end
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index e1acd1f77..e3d6880ba 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -186,7 +186,7 @@ class Pathname
       begin
         tf.chown(uid, gid)
         tf.chmod(old_stat.mode)
-      rescue Errno::EPERM
+      rescue Errno::EPERM # rubocop:disable Lint/HandleExceptions
       end
 
       File.rename(tf.path, self)
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index d999b9c5f..61042aae7 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1041,14 +1041,14 @@ class Formula
     # keg's formula is deleted.
     begin
       keg = Keg.for(path)
-    rescue NotAKegError, Errno::ENOENT
+    rescue NotAKegError, Errno::ENOENT # rubocop:disable Lint/HandleExceptions
       # file doesn't belong to any keg.
     else
       tab_tap = Tab.for_keg(keg).tap
       return false if tab_tap.nil? # this keg doesn't below to any core/tap formula, most likely coming from a DIY install.
       begin
         Formulary.factory(keg.name)
-      rescue FormulaUnavailableError
+      rescue FormulaUnavailableError # rubocop:disable Lint/HandleExceptions
         # formula for this keg is deleted, so defer to whitelist
       rescue TapFormulaAmbiguityError, TapFormulaWithOldnameAmbiguityError
         return false # this keg belongs to another formula
@@ -1379,12 +1379,13 @@ class Formula
   # An array of all installed {Formula}
   # @private
   def self.installed
-    @installed ||= racks.map do |rack|
+    @installed ||= racks.flat_map do |rack|
       begin
         Formulary.from_rack(rack)
       rescue FormulaUnavailableError, TapFormulaAmbiguityError, TapFormulaWithOldnameAmbiguityError
+        []
       end
-    end.compact.uniq(&:name)
+    end.uniq(&:name)
   end
 
   def self.installed_with_alias_path(alias_path)
@@ -1642,7 +1643,7 @@ class Formula
         with_logging("test") do
           test
         end
-      rescue Exception
+      rescue Exception # rubocop:disable Lint/RescueException
         staging.retain! if ARGV.debug?
         raise
       end
@@ -1667,8 +1668,7 @@ class Formula
   end
 
   # @private
-  def test
-  end
+  def test; end
 
   # @private
   def test_fixtures(file)
@@ -1683,8 +1683,7 @@ class Formula
   #   system "./configure", "--prefix=#{prefix}"
   #   system "make", "install"
   # end</pre>
-  def install
-  end
+  def install; end
 
   protected
 
@@ -1932,28 +1931,28 @@ class Formula
     end
   end
 
-  def self.method_added(method)
-    case method
-    when :brew
-      raise "You cannot override Formula#brew in class #{name}"
-    when :test
-      define_method(:test_defined?) { true }
-    when :options
-      instance = allocate
+  # The methods below define the formula DSL.
+  class << self
+    include BuildEnvironment::DSL
 
-      specs.each do |spec|
-        instance.options.each do |opt, desc|
-          spec.option(opt[/^--(.+)$/, 1], desc)
+    def method_added(method)
+      case method
+      when :brew
+        raise "You cannot override Formula#brew in class #{name}"
+      when :test
+        define_method(:test_defined?) { true }
+      when :options
+        instance = allocate
+
+        specs.each do |spec|
+          instance.options.each do |opt, desc|
+            spec.option(opt[/^--(.+)$/, 1], desc)
+          end
         end
-      end
 
-      remove_method(:options)
+        remove_method(:options)
+      end
     end
-  end
-
-  # The methods below define the formula DSL.
-  class << self
-    include BuildEnvironment::DSL
 
     # The reason for why this software is not linked (by default) to
     # {::HOMEBREW_PREFIX}.
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 56238ad73..7cd87e751 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -58,13 +58,14 @@ class FormulaInstaller
     @options = Options.new
     @invalid_option_names = []
     @requirement_messages = []
-
-    @@attempted ||= Set.new
-
     @poured_bottle = false
     @pour_failed   = false
   end
 
+  def self.attempted
+    @attempted ||= Set.new
+  end
+
   # When no build tools are available and build flags are passed through ARGV,
   # it's necessary to interrupt the user before any sort of installation
   # can proceed. Only invoked when the user has no developer tools.
@@ -145,7 +146,7 @@ class FormulaInstaller
   end
 
   def check_install_sanity
-    raise FormulaInstallationAlreadyAttemptedError, formula if @@attempted.include?(formula)
+    raise FormulaInstallationAlreadyAttemptedError, formula if self.class.attempted.include?(formula)
 
     return if ignore_deps?
 
@@ -287,12 +288,12 @@ class FormulaInstaller
       end
     end
 
-    @@attempted << formula
+    self.class.attempted << formula
 
     if pour_bottle?(warn: true)
       begin
         pour
-      rescue Exception => e
+      rescue Exception => e # rubocop:disable Lint/RescueException
         # any exceptions must leave us with nothing installed
         ignore_interrupts do
           formula.prefix.rmtree if formula.prefix.directory?
@@ -567,7 +568,7 @@ class FormulaInstaller
     oh1 "Installing #{formula.full_name} dependency: #{Formatter.identifier(dep.name)}"
     fi.install
     fi.finish
-  rescue Exception
+  rescue Exception # rubocop:disable Lint/RescueException
     ignore_interrupts do
       tmp_keg.rename(installed_keg) if tmp_keg && !installed_keg.directory?
       linked_keg.link if keg_was_linked
@@ -723,7 +724,7 @@ class FormulaInstaller
     if !formula.prefix.directory? || Keg.new(formula.prefix).empty_installation?
       raise "Empty installation"
     end
-  rescue Exception => e
+  rescue Exception => e # rubocop:disable Lint/RescueException
     e.options = display_options(formula) if e.is_a?(BuildError)
     ignore_interrupts do
       # any exceptions must leave us with nothing installed
@@ -784,7 +785,7 @@ class FormulaInstaller
       puts "  brew link #{formula.name}"
       @show_summary_heading = true
       Homebrew.failed = true
-    rescue Exception => e
+    rescue Exception => e # rubocop:disable Lint/RescueException
       onoe "An unexpected error occurred during the `brew link` step"
       puts "The formula built, but is not symlinked into #{HOMEBREW_PREFIX}"
       puts e
@@ -815,7 +816,7 @@ class FormulaInstaller
     formula.plist_path.chmod 0644
     log = formula.var/"log"
     log.mkpath if formula.plist.include? log.to_s
-  rescue Exception => e
+  rescue Exception => e # rubocop:disable Lint/RescueException
     onoe "Failed to install plist file"
     ohai e, e.backtrace if debug?
     Homebrew.failed = true
@@ -823,7 +824,7 @@ class FormulaInstaller
 
   def fix_dynamic_linkage(keg)
     keg.fix_dynamic_linkage
-  rescue Exception => e
+  rescue Exception => e # rubocop:disable Lint/RescueException
     onoe "Failed to fix install linkage"
     puts "The formula built, but you may encounter issues using it or linking other"
     puts "formula against it."
@@ -835,7 +836,7 @@ class FormulaInstaller
   def clean
     ohai "Cleaning" if verbose?
     Cleaner.new(formula).clean
-  rescue Exception => e
+  rescue Exception => e # rubocop:disable Lint/RescueException
     opoo "The cleaning step did not complete successfully"
     puts "Still, the installation was successful, so we will link it into your prefix"
     ohai e, e.backtrace if debug?
@@ -845,7 +846,7 @@ class FormulaInstaller
 
   def post_install
     Homebrew.run_post_install(formula)
-  rescue Exception => e
+  rescue Exception => e # rubocop:disable Lint/RescueException
     opoo "The post-install step did not complete successfully"
     puts "You can try again using `brew postinstall #{formula.full_name}`"
     ohai e, e.backtrace if debug?
@@ -905,27 +906,31 @@ class FormulaInstaller
     super
   end
 
+  def self.locked
+    @locked ||= []
+  end
+
   private
 
   attr_predicate :hold_locks?
 
   def lock
-    return unless (@@locked ||= []).empty?
+    return unless self.class.locked.empty?
     unless ignore_deps?
       formula.recursive_dependencies.each do |dep|
-        @@locked << dep.to_formula
+        self.class.locked << dep.to_formula
       end
     end
-    @@locked.unshift(formula)
-    @@locked.uniq!
-    @@locked.each(&:lock)
+    self.class.locked.unshift(formula)
+    self.class.locked.uniq!
+    self.class.locked.each(&:lock)
     @hold_locks = true
   end
 
   def unlock
     return unless hold_locks?
-    @@locked.each(&:unlock)
-    @@locked.clear
+    self.class.locked.each(&:unlock)
+    self.class.locked.clear
     @hold_locks = false
   end
 
diff --git a/Library/Homebrew/formula_versions.rb b/Library/Homebrew/formula_versions.rb
index bb6803567..c10c69e67 100644
--- a/Library/Homebrew/formula_versions.rb
+++ b/Library/Homebrew/formula_versions.rb
@@ -44,7 +44,7 @@ class FormulaVersions
     # continue walking the history
     ohai "#{e} in #{name} at revision #{rev}", e.backtrace if ARGV.debug?
   rescue FormulaUnavailableError
-    # Suppress this error
+    return
   ensure
     Homebrew.raise_deprecation_exceptions = false
   end
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index 0eb34ee2a..fddeac631 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -1,18 +1,19 @@
 require "digest/md5"
 require "tap"
+require "extend/cachable"
 
 # The Formulary is responsible for creating instances of Formula.
 # It is not meant to be used directly from formulae.
 
 module Formulary
-  FORMULAE = {}
+  extend Cachable
 
   def self.formula_class_defined?(path)
-    FORMULAE.key?(path)
+    cache.key?(path)
   end
 
   def self.formula_class_get(path)
-    FORMULAE.fetch(path)
+    cache.fetch(path)
   end
 
   def self.load_formula(name, path, contents, namespace)
@@ -44,7 +45,7 @@ module Formulary
     contents = path.open("r") { |f| ensure_utf8_encoding(f).read }
     namespace = "FormulaNamespace#{Digest::MD5.hexdigest(path.to_s)}"
     klass = load_formula(name, path, contents, namespace)
-    FORMULAE[path] = klass
+    cache[path] = klass
   end
 
   if IO.method_defined?(:set_encoding)
diff --git a/Library/Homebrew/migrator.rb b/Library/Homebrew/migrator.rb
index 7ecdafe2f..0eb7492df 100644
--- a/Library/Homebrew/migrator.rb
+++ b/Library/Homebrew/migrator.rb
@@ -100,7 +100,7 @@ class Migrator
     begin
       migrator = Migrator.new(formula)
       migrator.migrate
-    rescue Exception => e
+    rescue => e
       onoe e
     end
   end
@@ -196,7 +196,7 @@ class Migrator
     update_tabs
   rescue Interrupt
     ignore_interrupts { backup_oldname }
-  rescue Exception => e
+  rescue Exception => e # rubocop:disable Lint/RescueException
     onoe "Error occurred while migrating."
     puts e
     puts e.backtrace if ARGV.debug?
@@ -304,7 +304,7 @@ class Migrator
       puts
       puts "You can try again using:"
       puts "  brew link #{formula.name}"
-    rescue Exception => e
+    rescue Exception => e # rubocop:disable Lint/RescueException
       onoe "An unexpected error occurred during linking"
       puts e
       puts e.backtrace if ARGV.debug?
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index 59e7026bd..5071aafcf 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -183,7 +183,7 @@ module OS
     end
 
     module CLT
-      extend self
+      module_function
 
       STANDALONE_PKG_ID = "com.apple.pkg.DeveloperToolsCLILeo".freeze
       FROM_XCODE_PKG_ID = "com.apple.pkg.DeveloperToolsCLI".freeze
diff --git a/Library/Homebrew/patch.rb b/Library/Homebrew/patch.rb
index 7045adf5e..8a1b00930 100644
--- a/Library/Homebrew/patch.rb
+++ b/Library/Homebrew/patch.rb
@@ -60,8 +60,7 @@ class EmbeddedPatch
     false
   end
 
-  def contents
-  end
+  def contents; end
 
   def apply
     data = contents.gsub("HOMEBREW_PREFIX", HOMEBREW_PREFIX)
@@ -87,10 +86,13 @@ class DATAPatch < EmbeddedPatch
   def contents
     data = ""
     path.open("rb") do |f|
-      begin
+      loop do
         line = f.gets
-      end until line.nil? || line =~ /^__END__$/
-      data << line while line = f.gets
+        break if line.nil? || line =~ /^__END__$/
+      end
+      while line = f.gets
+        data << line
+      end
     end
     data
   end
diff --git a/Library/Homebrew/postinstall.rb b/Library/Homebrew/postinstall.rb
index 0b6d8f6b0..53a5b7e75 100644
--- a/Library/Homebrew/postinstall.rb
+++ b/Library/Homebrew/postinstall.rb
@@ -14,7 +14,7 @@ begin
   formula = ARGV.resolved_formulae.first
   formula.extend(Debrew::Formula) if ARGV.debug?
   formula.run_post_install
-rescue Exception => e
+rescue Exception => e # rubocop:disable Lint/RescueException
   Marshal.dump(e, error_pipe)
   error_pipe.close
   exit! 1
diff --git a/Library/Homebrew/readall.rb b/Library/Homebrew/readall.rb
index 3595c16be..5f4fd947c 100644
--- a/Library/Homebrew/readall.rb
+++ b/Library/Homebrew/readall.rb
@@ -52,7 +52,7 @@ module Readall
           Formulary.factory(file)
         rescue Interrupt
           raise
-        rescue Exception => e
+        rescue Exception => e # rubocop:disable Lint/RescueException
           onoe "Invalid formula: #{file}"
           puts e
           failed = true
diff --git a/Library/Homebrew/tab.rb b/Library/Homebrew/tab.rb
index af19cabe6..aa0208d51 100644
--- a/Library/Homebrew/tab.rb
+++ b/Library/Homebrew/tab.rb
@@ -3,18 +3,16 @@ require "ostruct"
 require "options"
 require "json"
 require "development_tools"
+require "extend/cachable"
 
 # Inherit from OpenStruct to gain a generic initialization method that takes a
 # hash and creates an attribute for each key and value. `Tab.new` probably
 # should not be called directly, instead use one of the class methods like
 # `Tab.create`.
 class Tab < OpenStruct
-  FILENAME = "INSTALL_RECEIPT.json".freeze
-  CACHE = {}
+  extend Cachable
 
-  def self.clear_cache
-    CACHE.clear
-  end
+  FILENAME = "INSTALL_RECEIPT.json".freeze
 
   # Instantiates a Tab for a new installation of a formula.
   def self.create(formula, compiler, stdlib)
@@ -57,7 +55,7 @@ class Tab < OpenStruct
   # Returns the Tab for an install receipt at `path`.
   # Results are cached.
   def self.from_file(path)
-    CACHE.fetch(path) { |p| CACHE[p] = from_file_content(File.read(p), p) }
+    cache.fetch(path) { |p| cache[p] = from_file_content(File.read(p), p) }
   end
 
   # Like Tab.from_file, but bypass the cache.
@@ -343,7 +341,7 @@ class Tab < OpenStruct
     # will no longer be valid.
     Formula.clear_installed_formulae_cache unless tabfile.exist?
 
-    CACHE[tabfile] = self
+    self.class.cache[tabfile] = self
     tabfile.atomic_write(to_json)
   end
 
diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index f4e7631b4..78dc4cf4e 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -1,4 +1,5 @@
 require "extend/string"
+require "extend/cachable"
 require "readall"
 
 # a {Tap} is used to extend the formulae provided by Homebrew core.
@@ -8,13 +9,9 @@ require "readall"
 # {#user} represents Github username and {#repo} represents repository
 # name without leading `homebrew-`.
 class Tap
-  TAP_DIRECTORY = HOMEBREW_LIBRARY/"Taps"
-
-  CACHE = {}
+  extend Cachable
 
-  def self.clear_cache
-    CACHE.clear
-  end
+  TAP_DIRECTORY = HOMEBREW_LIBRARY/"Taps"
 
   def self.fetch(*args)
     case args.length
@@ -38,7 +35,7 @@ class Tap
     end
 
     cache_key = "#{user}/#{repo}".downcase
-    CACHE.fetch(cache_key) { |key| CACHE[key] = Tap.new(user, repo) }
+    cache.fetch(cache_key) { |key| cache[key] = Tap.new(user, repo) }
   end
 
   def self.from_path(path)
diff --git a/Library/Homebrew/test.rb b/Library/Homebrew/test.rb
index d9ec8250e..3d5e62a88 100644
--- a/Library/Homebrew/test.rb
+++ b/Library/Homebrew/test.rb
@@ -27,7 +27,7 @@ begin
   Timeout.timeout TEST_TIMEOUT_SECONDS do
     raise "test returned false" if formula.run_test == false
   end
-rescue Exception => e
+rescue Exception => e # rubocop:disable Lint/RescueException
   Marshal.dump(e, error_pipe)
   error_pipe.close
   exit! 1
diff --git a/Library/Homebrew/test/formula_installer_spec.rb b/Library/Homebrew/test/formula_installer_spec.rb
index 7365b2758..7b729312b 100644
--- a/Library/Homebrew/test/formula_installer_spec.rb
+++ b/Library/Homebrew/test/formula_installer_spec.rb
@@ -107,7 +107,7 @@ describe FormulaInstaller do
       end
     EOS
 
-    Formulary::FORMULAE.delete(dep_path)
+    Formulary.cache.delete(dep_path)
     dependency = Formulary.factory(dep_name)
 
     dependent = formula do
diff --git a/Library/Homebrew/utils.rb b/Library/Homebrew/utils.rb
index d293b2a6f..237ffa74e 100644
--- a/Library/Homebrew/utils.rb
+++ b/Library/Homebrew/utils.rb
@@ -229,10 +229,9 @@ module Homebrew
     EOS
   end
 
-  # Hash of Module => Set(method_names)
-  @injected_dump_stat_modules = {}
-
+  # rubocop:disable Style/GlobalVars
   def inject_dump_stats!(the_module, pattern)
+    @injected_dump_stat_modules ||= {}
     @injected_dump_stat_modules[the_module] ||= []
     injected_methods = @injected_dump_stat_modules[the_module]
     the_module.module_eval do
@@ -260,6 +259,7 @@ module Homebrew
       end
     end
   end
+  # rubocop:enable Style/GlobalVars
 end
 
 def with_system_path
diff --git a/Library/Homebrew/utils/fork.rb b/Library/Homebrew/utils/fork.rb
index 2f2a403e2..57ddbfae2 100644
--- a/Library/Homebrew/utils/fork.rb
+++ b/Library/Homebrew/utils/fork.rb
@@ -14,7 +14,7 @@ module Utils
             read.close
             write.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
             yield
-          rescue Exception => e
+          rescue Exception => e # rubocop:disable Lint/RescueException
             Marshal.dump(e, write)
             write.close
             exit!
@@ -26,8 +26,11 @@ module Utils
         ignore_interrupts(:quietly) do # the child will receive the interrupt and marshal it back
           begin
             socket = server.accept_nonblock
+          # rubocop:disable Lint/ShadowedException
+          # FIXME: https://github.com/bbatsov/rubocop/issues/4843
           rescue Errno::EAGAIN, Errno::EWOULDBLOCK, Errno::ECONNABORTED, Errno::EPROTO, Errno::EINTR
             retry unless Process.waitpid(pid, Process::WNOHANG)
+          # rubocop:enable Lint/ShadowedException
           else
             socket.send_io(write)
             socket.close
@@ -36,7 +39,7 @@ module Utils
           data = read.read
           read.close
           Process.wait(pid) unless socket.nil?
-          raise Marshal.load(data) unless data.nil? || data.empty?
+          raise Marshal.load(data) unless data.nil? || data.empty? # rubocop:disable Security/MarshalLoad
           raise Interrupt if $CHILD_STATUS.exitstatus == 130
           raise "Forked child process failed: #{$CHILD_STATUS}" unless $CHILD_STATUS.success?
         end
diff --git a/Library/Homebrew/version.rb b/Library/Homebrew/version.rb
index 3ac748037..d43e0c665 100644
--- a/Library/Homebrew/version.rb
+++ b/Library/Homebrew/version.rb
@@ -213,110 +213,6 @@ class Version
     end
   end
 
-  def initialize(val)
-    unless val.respond_to?(:to_str)
-      raise TypeError, "Version value must be a string; got a #{val.class} (#{val})"
-    end
-    @version = val.to_str
-  end
-
-  def detected_from_url?
-    false
-  end
-
-  def head?
-    false
-  end
-
-  def null?
-    false
-  end
-
-  def <=>(other)
-    # Needed to retain API compatibility with older string comparisons
-    # for compiler versions, etc.
-    other = Version.new(other) if other.is_a? String
-    # Used by the *_build_version comparisons, which formerly returned Fixnum
-    other = Version.new(other.to_s) if other.is_a? Integer
-    return 1 if other.nil?
-
-    return unless other.is_a?(Version)
-    return 0 if version == other.version
-    return 1 if head? && !other.head?
-    return -1 if !head? && other.head?
-    return 0 if head? && other.head?
-
-    ltokens = tokens
-    rtokens = other.tokens
-    max = max(ltokens.length, rtokens.length)
-    l = r = 0
-
-    while l < max
-      a = ltokens[l] || NULL_TOKEN
-      b = rtokens[r] || NULL_TOKEN
-
-      if a == b
-        l += 1
-        r += 1
-        next
-      elsif a.numeric? && b.numeric?
-        return a <=> b
-      elsif a.numeric?
-        return 1 if a > NULL_TOKEN
-        l += 1
-      elsif b.numeric?
-        return -1 if b > NULL_TOKEN
-        r += 1
-      else
-        return a <=> b
-      end
-    end
-
-    0
-  end
-  alias eql? ==
-
-  def hash
-    version.hash
-  end
-
-  def to_f
-    version.to_f
-  end
-
-  def to_s
-    version.dup
-  end
-  alias to_str to_s
-
-  protected
-
-  attr_reader :version
-
-  def tokens
-    @tokens ||= tokenize
-  end
-
-  private
-
-  def max(a, b)
-    (a > b) ? a : b
-  end
-
-  def tokenize
-    version.scan(SCAN_PATTERN).map! do |token|
-      case token
-      when /\A#{AlphaToken::PATTERN}\z/o   then AlphaToken
-      when /\A#{BetaToken::PATTERN}\z/o    then BetaToken
-      when /\A#{RCToken::PATTERN}\z/o      then RCToken
-      when /\A#{PreToken::PATTERN}\z/o     then PreToken
-      when /\A#{PatchToken::PATTERN}\z/o   then PatchToken
-      when /\A#{NumericToken::PATTERN}\z/o then NumericToken
-      when /\A#{StringToken::PATTERN}\z/o  then StringToken
-      end.new(token)
-    end
-  end
-
   def self.parse(spec)
     version = _parse(spec)
     version.nil? ? NULL : new(version)
@@ -461,6 +357,112 @@ class Version
     m = /[-.vV]?((?:\d+\.)+\d+(?:[-_.]?(?i:alpha|beta|pre|rc)\.?\d{,2})?)/.match(spec_s)
     return m.captures.first unless m.nil?
   end
+
+  private_class_method :_parse
+
+  def initialize(val)
+    unless val.respond_to?(:to_str)
+      raise TypeError, "Version value must be a string; got a #{val.class} (#{val})"
+    end
+    @version = val.to_str
+  end
+
+  def detected_from_url?
+    false
+  end
+
+  def head?
+    false
+  end
+
+  def null?
+    false
+  end
+
+  def <=>(other)
+    # Needed to retain API compatibility with older string comparisons
+    # for compiler versions, etc.
+    other = Version.new(other) if other.is_a? String
+    # Used by the *_build_version comparisons, which formerly returned Fixnum
+    other = Version.new(other.to_s) if other.is_a? Integer
+    return 1 if other.nil?
+
+    return unless other.is_a?(Version)
+    return 0 if version == other.version
+    return 1 if head? && !other.head?
+    return -1 if !head? && other.head?
+    return 0 if head? && other.head?
+
+    ltokens = tokens
+    rtokens = other.tokens
+    max = max(ltokens.length, rtokens.length)
+    l = r = 0
+
+    while l < max
+      a = ltokens[l] || NULL_TOKEN
+      b = rtokens[r] || NULL_TOKEN
+
+      if a == b
+        l += 1
+        r += 1
+        next
+      elsif a.numeric? && b.numeric?
+        return a <=> b
+      elsif a.numeric?
+        return 1 if a > NULL_TOKEN
+        l += 1
+      elsif b.numeric?
+        return -1 if b > NULL_TOKEN
+        r += 1
+      else
+        return a <=> b
+      end
+    end
+
+    0
+  end
+  alias eql? ==
+
+  def hash
+    version.hash
+  end
+
+  def to_f
+    version.to_f
+  end
+
+  def to_s
+    version.dup
+  end
+  alias to_str to_s
+
+  protected
+
+  attr_reader :version
+
+  def tokens
+    @tokens ||= tokenize
+  end
+
+  private
+
+  def max(a, b)
+    (a > b) ? a : b
+  end
+
+  def tokenize
+    version.scan(SCAN_PATTERN).map! do |token|
+      case token
+      when /\A#{AlphaToken::PATTERN}\z/o   then AlphaToken
+      when /\A#{BetaToken::PATTERN}\z/o    then BetaToken
+      when /\A#{RCToken::PATTERN}\z/o      then RCToken
+      when /\A#{PreToken::PATTERN}\z/o     then PreToken
+      when /\A#{PatchToken::PATTERN}\z/o   then PatchToken
+      when /\A#{NumericToken::PATTERN}\z/o then NumericToken
+      when /\A#{StringToken::PATTERN}\z/o  then StringToken
+      end.new(token)
+    end
+  end
 end
 
 class HeadVersion < Version