Fix Style/GuardClause.

33 files changed, 324 insertions, 414 deletions

diff --git a/Library/.rubocop_todo.yml b/Library/.rubocop_todo.yml
index 1799ebef5..7f86119ab 100644
--- a/Library/.rubocop_todo.yml
+++ b/Library/.rubocop_todo.yml
@@ -118,43 +118,6 @@ Style/GlobalVars:
     - 'Homebrew/diagnostic.rb'
     - 'Homebrew/utils.rb'
 
-# Offense count: 70
-# Configuration parameters: MinBodyLength.
-Style/GuardClause:
-  Exclude:
-    - 'Taps/**/*'
-    - 'Homebrew/cmd/update-report.rb'
-    - 'Homebrew/dependency_collector.rb'
-    - 'Homebrew/dev-cmd/audit.rb'
-    - 'Homebrew/dev-cmd/pull.rb'
-    - 'Homebrew/dev-cmd/test-bot.rb'
-    - 'Homebrew/download_strategy.rb'
-    - 'Homebrew/extend/ARGV.rb'
-    - 'Homebrew/extend/ENV/shared.rb'
-    - 'Homebrew/extend/ENV/std.rb'
-    - 'Homebrew/extend/ENV/super.rb'
-    - 'Homebrew/extend/fileutils.rb'
-    - 'Homebrew/extend/os/mac/extend/ENV/std.rb'
-    - 'Homebrew/extend/os/mac/formula_cellar_checks.rb'
-    - 'Homebrew/extend/os/mac/utils/bottles.rb'
-    - 'Homebrew/extend/string.rb'
-    - 'Homebrew/formula.rb'
-    - 'Homebrew/formula_installer.rb'
-    - 'Homebrew/formula_lock.rb'
-    - 'Homebrew/formulary.rb'
-    - 'Homebrew/keg.rb'
-    - 'Homebrew/migrator.rb'
-    - 'Homebrew/os/mac/xcode.rb'
-    - 'Homebrew/patch.rb'
-    - 'Homebrew/requirement.rb'
-    - 'Homebrew/tap.rb'
-    - 'Homebrew/test/test_cmd_testbot.rb'
-    - 'Homebrew/test/test_integration_cmds.rb'
-    - 'Homebrew/test/testing_env.rb'
-    - 'Homebrew/utils.rb'
-    - 'Homebrew/utils/popen.rb'
-    - 'Homebrew/version.rb'
-
 # Offense count: 51
 # Cop supports --auto-correct.
 # Configuration parameters: MaxLineLength.
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index 0a6dd5a46..8a8323252 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -203,13 +203,12 @@ module Homebrew
         # If they haven't updated in 48 hours (172800 seconds), that
         # might explain the error
         master = HOMEBREW_REPOSITORY/".git/refs/heads/master"
-        if master.exist? && (Time.now.to_i - File.mtime(master).to_i) > 172800
-          ohai "You haven't updated Homebrew in a while."
-          puts <<-EOS.undent
-            A formula for #{e.name} might have been added recently.
-            Run `brew update` to get the latest Homebrew updates!
-          EOS
-        end
+        return unless master.exist? && (Time.now.to_i - File.mtime(master).to_i) > 172800
+        ohai "You haven't updated Homebrew in a while."
+        puts <<-EOS.undent
+          A formula for #{e.name} might have been added recently.
+          Run `brew update` to get the latest Homebrew updates!
+        EOS
       end
     end
   end
diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 1e9c8ccd3..18f2f370c 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -549,11 +549,10 @@ class ReporterHub
       end
     end
 
-    unless formulae.empty?
-      # Dump formula list.
-      ohai title
-      puts_columns(formulae)
-    end
+    return if formulae.empty?
+    # Dump formula list.
+    ohai title
+    puts_columns(formulae)
   end
 
   def installed?(formula)
diff --git a/Library/Homebrew/dependency_collector.rb b/Library/Homebrew/dependency_collector.rb
index 0b35e7fb4..56463fa29 100644
--- a/Library/Homebrew/dependency_collector.rb
+++ b/Library/Homebrew/dependency_collector.rb
@@ -128,11 +128,11 @@ class DependencyCollector
   end
 
   def parse_class_spec(spec, tags)
-    if spec < Requirement
-      spec.new(tags)
-    else
+    unless spec < Requirement
       raise TypeError, "#{spec.inspect} is not a Requirement subclass"
     end
+
+    spec.new(tags)
   end
 
   def ant_dep(spec, tags)
diff --git a/Library/Homebrew/dev-cmd/audit.rb b/Library/Homebrew/dev-cmd/audit.rb
index 61d136daf..1a6e47dbe 100644
--- a/Library/Homebrew/dev-cmd/audit.rb
+++ b/Library/Homebrew/dev-cmd/audit.rb
@@ -284,9 +284,8 @@ class FormulaAuditor
       problem "Should not have both `head` and `head do`"
     end
 
-    if present.include?("bottle modifier") && present.include?("bottle block")
-      problem "Should not have `bottle :unneeded/:disable` and `bottle do`"
-    end
+    return unless present.include?("bottle modifier") && present.include?("bottle block")
+    problem "Should not have `bottle :unneeded/:disable` and `bottle do`"
   end
 
   def audit_class
@@ -350,9 +349,8 @@ class FormulaAuditor
 
     same_name_tap_formulae.delete(full_name)
 
-    unless same_name_tap_formulae.empty?
-      problem "Formula name conflicts with #{same_name_tap_formulae.join ", "}"
-    end
+    return if same_name_tap_formulae.empty?
+    problem "Formula name conflicts with #{same_name_tap_formulae.join ", "}"
   end
 
   def audit_deps
@@ -485,9 +483,8 @@ class FormulaAuditor
       problem "Description shouldn't start with an indefinite article (#{$1})"
     end
 
-    if desc.downcase.start_with? "#{formula.name} "
-      problem "Description shouldn't include the formula name"
-    end
+    return unless desc.downcase.start_with? "#{formula.name} "
+    problem "Description shouldn't include the formula name"
   end
 
   def audit_homepage
@@ -564,9 +561,9 @@ class FormulaAuditor
   end
 
   def audit_bottle_spec
-    if formula.bottle_disabled? && !formula.bottle_disable_reason.valid?
-      problem "Unrecognized bottle modifier"
-    end
+    return unless formula.bottle_disabled?
+    return if formula.bottle_disable_reason.valid?
+    problem "Unrecognized bottle modifier"
   end
 
   def audit_github_repository
@@ -594,9 +591,8 @@ class FormulaAuditor
       problem "GitHub repository not notable enough (<20 forks, <20 watchers and <50 stars)"
     end
 
-    if Date.parse(metadata["created_at"]) > (Date.today - 30)
-      problem "GitHub repository too new (<30 days old)"
-    end
+    return if Date.parse(metadata["created_at"]) <= (Date.today - 30)
+    problem "GitHub repository too new (<30 days old)"
   end
 
   def audit_specs
@@ -736,9 +732,8 @@ class FormulaAuditor
       problem "Please set plist_options when using a formula-defined plist."
     end
 
-    if text.include?('require "language/go"') && !text.include?("go_resource")
-      problem "require \"language/go\" is unnecessary unless using `go_resource`s"
-    end
+    return unless text.include?('require "language/go"') && !text.include?("go_resource")
+    problem "require \"language/go\" is unnecessary unless using `go_resource`s"
   end
 
   def audit_line(line, lineno)
@@ -983,9 +978,8 @@ class FormulaAuditor
       problem "Use \#{pkgshare} instead of \#{share}/#{formula.name}"
     end
 
-    if line =~ %r{share(\s*[/+]\s*)(['"])#{Regexp.escape(formula.name)}(?:\2|/)}
-      problem "Use pkgshare instead of (share#{$1}\"#{formula.name}\")"
-    end
+    return unless line =~ %r{share(\s*[/+]\s*)(['"])#{Regexp.escape(formula.name)}(?:\2|/)}
+    problem "Use pkgshare instead of (share#{$1}\"#{formula.name}\")"
   end
 
   def audit_caveats
@@ -1115,9 +1109,8 @@ class ResourceAuditor
       problem "version #{version} should not have a leading 'v'"
     end
 
-    if version.to_s =~ /_\d+$/
-      problem "version #{version} should not end with an underline and a number"
-    end
+    return unless version.to_s =~ /_\d+$/
+    problem "version #{version} should not end with an underline and a number"
   end
 
   def audit_checksum
@@ -1183,9 +1176,8 @@ class ResourceAuditor
       end
     end
 
-    if url_strategy == DownloadStrategyDetector.detect("", using)
-      problem "Redundant :using value in URL"
-    end
+    return unless url_strategy == DownloadStrategyDetector.detect("", using)
+    problem "Redundant :using value in URL"
   end
 
   def audit_urls
diff --git a/Library/Homebrew/dev-cmd/pull.rb b/Library/Homebrew/dev-cmd/pull.rb
index b06719fb1..857c55993 100644
--- a/Library/Homebrew/dev-cmd/pull.rb
+++ b/Library/Homebrew/dev-cmd/pull.rb
@@ -531,19 +531,19 @@ module Homebrew
             req = Net::HTTP::Head.new bottle_info.url
             req.initialize_http_header "User-Agent" => HOMEBREW_USER_AGENT_RUBY
             res = http.request req
-            if res.is_a?(Net::HTTPSuccess)
-              break
-            elsif res.is_a?(Net::HTTPClientError)
-              if retry_count >= max_retries
-                raise "Failed to find published #{f} bottle at #{url}!"
-              end
-              print(wrote_dots ? "." : "Waiting on Bintray.")
-              wrote_dots = true
-              sleep poll_retry_delay_seconds
-              retry_count += 1
-            else
+            break if res.is_a?(Net::HTTPSuccess)
+
+            unless res.is_a?(Net::HTTPClientError)
               raise "Failed to find published #{f} bottle at #{url} (#{res.code} #{res.message})!"
             end
+
+            if retry_count >= max_retries
+              raise "Failed to find published #{f} bottle at #{url}!"
+            end
+            print(wrote_dots ? "." : "Waiting on Bintray.")
+            wrote_dots = true
+            sleep poll_retry_delay_seconds
+            retry_count += 1
           end
         end
 
diff --git a/Library/Homebrew/dev-cmd/test-bot.rb b/Library/Homebrew/dev-cmd/test-bot.rb
index abf0235e5..935a40731 100644
--- a/Library/Homebrew/dev-cmd/test-bot.rb
+++ b/Library/Homebrew/dev-cmd/test-bot.rb
@@ -123,13 +123,12 @@ module Homebrew
       end
     end
 
-    if git_url = ENV["UPSTREAM_GIT_URL"] || ENV["GIT_URL"]
-      # Also can get tap from Jenkins GIT_URL.
-      url_path = git_url.sub(%r{^https?://github\.com/}, "").chomp("/").sub(/\.git$/, "")
-      begin
-        return Tap.fetch(url_path) if url_path =~ HOMEBREW_TAP_REGEX
-      rescue
-      end
+    return unless git_url = ENV["UPSTREAM_GIT_URL"] || ENV["GIT_URL"]
+    # Also can get tap from Jenkins GIT_URL.
+    url_path = git_url.sub(%r{^https?://github\.com/}, "").chomp("/").sub(/\.git$/, "")
+    begin
+      return Tap.fetch(url_path) if url_path =~ HOMEBREW_TAP_REGEX
+    rescue
     end
   end
 
@@ -1001,10 +1000,9 @@ module Homebrew
       end
     end
 
-    if git_tag
-      safe_system "git", "tag", "--force", git_tag
-      safe_system "git", "push", "--force", remote, "master:master", "refs/tags/#{git_tag}"
-    end
+    return unless git_tag
+    safe_system "git", "tag", "--force", git_tag
+    safe_system "git", "push", "--force", remote, "master:master", "refs/tags/#{git_tag}"
   end
 
   def sanitize_argv_and_env
@@ -1053,13 +1051,12 @@ module Homebrew
 
     ARGV << "--fast" if ARGV.include?("--ci-master")
 
-    if ARGV.include? "--local"
-      ENV["HOMEBREW_CACHE"] = "#{ENV["HOME"]}/Library/Caches/Homebrew"
-      mkdir_p ENV["HOMEBREW_CACHE"]
-      ENV["HOMEBREW_HOME"] = ENV["HOME"] = "#{Dir.pwd}/home"
-      mkdir_p ENV["HOME"]
-      ENV["HOMEBREW_LOGS"] = "#{Dir.pwd}/logs"
-    end
+    return unless ARGV.include?("--local")
+    ENV["HOMEBREW_CACHE"] = "#{ENV["HOME"]}/Library/Caches/Homebrew"
+    mkdir_p ENV["HOMEBREW_CACHE"]
+    ENV["HOMEBREW_HOME"] = ENV["HOME"] = "#{Dir.pwd}/home"
+    mkdir_p ENV["HOME"]
+    ENV["HOMEBREW_LOGS"] = "#{Dir.pwd}/logs"
   end
 
   def test_bot
diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index b852c1d5f..687e14396 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -158,14 +158,13 @@ class VCSDownloadStrategy < AbstractDownloadStrategy
 
     version.update_commit(last_commit) if head?
 
-    if @ref_type == :tag && @revision && current_revision
-      unless current_revision == @revision
-        raise <<-EOS.undent
-          #{@ref} tag should be #{@revision}
-          but is actually #{current_revision}
-        EOS
-      end
-    end
+    return unless @ref_type == :tag
+    return unless @revision && current_revision
+    return if current_revision == @revision
+    raise <<-EOS.undent
+      #{@ref} tag should be #{@revision}
+      but is actually #{current_revision}
+    EOS
   end
 
   def fetch_last_commit
@@ -336,14 +335,14 @@ class CurlDownloadStrategy < AbstractFileDownloadStrategy
       rescue ErrorDuringExecution
         # 33 == range not supported
         # try wiping the incomplete download and retrying once
-        if $?.exitstatus == 33 && had_incomplete_download
-          ohai "Trying a full download"
-          temporary_path.unlink
-          had_incomplete_download = false
-          retry
-        else
+        unless $?.exitstatus == 33 && had_incomplete_download
           raise CurlDownloadStrategyError, @url
         end
+
+        ohai "Trying a full download"
+        temporary_path.unlink
+        had_incomplete_download = false
+        retry
       end
       ignore_interrupts { temporary_path.rename(cached_location) }
     end
@@ -717,12 +716,12 @@ class GitDownloadStrategy < VCSDownloadStrategy
   end
 
   def update_repo
-    if @ref_type == :branch || !ref?
-      if !shallow_clone? && shallow_dir?
-        quiet_safe_system "git", "fetch", "origin", "--unshallow"
-      else
-        quiet_safe_system "git", "fetch", "origin"
-      end
+    return unless @ref_type == :branch || !ref?
+
+    if !shallow_clone? && shallow_dir?
+      quiet_safe_system "git", "fetch", "origin", "--unshallow"
+    else
+      quiet_safe_system "git", "fetch", "origin"
     end
   end
 
@@ -798,10 +797,10 @@ end
 class GitHubGitDownloadStrategy < GitDownloadStrategy
   def initialize(name, resource)
     super
-    if @url =~ %r{^https?://github\.com/([^/]+)/([^/]+)\.git$}
-      @user = $1
-      @repo = $2
-    end
+
+    return unless %r{^https?://github\.com/(?<user>[^/]+)/(?<repo>[^/]+)\.git$} =~ @url
+    @user = user
+    @repo = repo
   end
 
   def github_last_commit
diff --git a/Library/Homebrew/extend/ARGV.rb b/Library/Homebrew/extend/ARGV.rb
index 92b4cb898..ecd50ce06 100644
--- a/Library/Homebrew/extend/ARGV.rb
+++ b/Library/Homebrew/extend/ARGV.rb
@@ -88,11 +88,11 @@ module HomebrewArgvExtension
             Formulary.from_rack(rack)
           end
 
-          if (prefix = f.installed_prefix).directory?
-            Keg.new(prefix)
-          else
+          unless (prefix = f.installed_prefix).directory?
             raise MultipleVersionsInstalledError, rack.basename
           end
+
+          Keg.new(prefix)
         end
       rescue FormulaUnavailableError
         raise <<-EOS.undent
diff --git a/Library/Homebrew/extend/ENV/shared.rb b/Library/Homebrew/extend/ENV/shared.rb
index 447e4dd29..909dc4f94 100644
--- a/Library/Homebrew/extend/ENV/shared.rb
+++ b/Library/Homebrew/extend/ENV/shared.rb
@@ -289,12 +289,11 @@ module SharedEnvExtension
       EOS
     end
 
-    unless gcc_formula.opt_prefix.exist?
-      raise <<-EOS.undent
-      The requested Homebrew GCC was not installed. You must:
-        brew install #{gcc_formula.full_name}
-      EOS
-    end
+    return if gcc_formula.opt_prefix.exist?
+    raise <<-EOS.undent
+    The requested Homebrew GCC was not installed. You must:
+      brew install #{gcc_formula.full_name}
+    EOS
   end
 
   def permit_arch_flags; end
@@ -328,9 +327,8 @@ module SharedEnvExtension
   end
 
   def check_for_compiler_universal_support
-    if homebrew_cc =~ GNU_GCC_REGEXP
-      raise "Non-Apple GCC can't build universal binaries"
-    end
+    return unless homebrew_cc =~ GNU_GCC_REGEXP
+    raise "Non-Apple GCC can't build universal binaries"
   end
 
   def gcc_with_cxx11_support?(cc)
diff --git a/Library/Homebrew/extend/ENV/std.rb b/Library/Homebrew/extend/ENV/std.rb
index 68bc9499d..b56aa56f3 100644
--- a/Library/Homebrew/extend/ENV/std.rb
+++ b/Library/Homebrew/extend/ENV/std.rb
@@ -48,10 +48,9 @@ module Stdenv
 
     send(compiler)
 
-    if cc =~ GNU_GCC_REGEXP
-      gcc_formula = gcc_version_formula($&)
-      append_path "PATH", gcc_formula.opt_bin.to_s
-    end
+    return unless cc =~ GNU_GCC_REGEXP
+    gcc_formula = gcc_version_formula($&)
+    append_path "PATH", gcc_formula.opt_bin.to_s
   end
   alias generic_setup_build_environment setup_build_environment
 
@@ -174,10 +173,10 @@ module Stdenv
     append_to_cflags Hardware::CPU.universal_archs.as_arch_flags
     append "LDFLAGS", Hardware::CPU.universal_archs.as_arch_flags
 
-    if compiler != :clang && Hardware.is_32_bit?
-      # Can't mix "-march" for a 32-bit CPU  with "-arch x86_64"
-      replace_in_cflags(/-march=\S*/, "-Xarch_#{Hardware::CPU.arch_32_bit} \\0")
-    end
+    return if compiler == :clang
+    return unless Hardware.is_32_bit?
+    # Can't mix "-march" for a 32-bit CPU  with "-arch x86_64"
+    replace_in_cflags(/-march=\S*/, "-Xarch_#{Hardware::CPU.arch_32_bit} \\0")
   end
 
   def cxx11
diff --git a/Library/Homebrew/extend/ENV/super.rb b/Library/Homebrew/extend/ENV/super.rb
index 1c0271685..a3837c695 100644
--- a/Library/Homebrew/extend/ENV/super.rb
+++ b/Library/Homebrew/extend/ENV/super.rb
@@ -276,12 +276,12 @@ module Superenv
     self["HOMEBREW_ARCHFLAGS"] = Hardware::CPU.universal_archs.as_arch_flags
 
     # GCC doesn't accept "-march" for a 32-bit CPU with "-arch x86_64"
-    if compiler != :clang && Hardware::CPU.is_32_bit?
-      self["HOMEBREW_OPTFLAGS"] = self["HOMEBREW_OPTFLAGS"].sub(
-        /-march=\S*/,
-        "-Xarch_#{Hardware::CPU.arch_32_bit} \\0"
-      )
-    end
+    return if compiler == :clang
+    return unless Hardware::CPU.is_32_bit?
+    self["HOMEBREW_OPTFLAGS"] = self["HOMEBREW_OPTFLAGS"].sub(
+      /-march=\S*/,
+      "-Xarch_#{Hardware::CPU.arch_32_bit} \\0"
+    )
   end
 
   def permit_arch_flags
diff --git a/Library/Homebrew/extend/fileutils.rb b/Library/Homebrew/extend/fileutils.rb
index b889f9ded..8b8d21da4 100644
--- a/Library/Homebrew/extend/fileutils.rb
+++ b/Library/Homebrew/extend/fileutils.rb
@@ -89,10 +89,9 @@ module FileUtils
   # A version of mkdir that also changes to that folder in a block.
   def mkdir(name, &_block)
     old_mkdir(name)
-    if block_given?
-      chdir name do
-        yield
-      end
+    return unless block_given?
+    chdir name do
+      yield
     end
   end
   module_function :mkdir
diff --git a/Library/Homebrew/extend/os/mac/extend/ENV/std.rb b/Library/Homebrew/extend/os/mac/extend/ENV/std.rb
index 8efbd3bc9..4853ecf0c 100644
--- a/Library/Homebrew/extend/os/mac/extend/ENV/std.rb
+++ b/Library/Homebrew/extend/os/mac/extend/ENV/std.rb
@@ -20,14 +20,13 @@ module Stdenv
 
     # Leopard's ld needs some convincing that it's building 64-bit
     # See: https://github.com/mistydemeo/tigerbrew/issues/59
-    if MacOS.version == :leopard && MacOS.prefer_64_bit?
-      append "LDFLAGS", "-arch #{Hardware::CPU.arch_64_bit}"
+    return unless MacOS.version == :leopard && MacOS.prefer_64_bit?
+    append "LDFLAGS", "-arch #{Hardware::CPU.arch_64_bit}"
 
-      # Many, many builds are broken thanks to Leopard's buggy ld.
-      # Our ld64 fixes many of those builds, though of course we can't
-      # depend on it already being installed to build itself.
-      ld64 if Formula["ld64"].installed?
-    end
+    # Many, many builds are broken thanks to Leopard's buggy ld.
+    # Our ld64 fixes many of those builds, though of course we can't
+    # depend on it already being installed to build itself.
+    ld64 if Formula["ld64"].installed?
   end
 
   def homebrew_extra_pkg_config_paths
@@ -65,19 +64,18 @@ module Stdenv
     delete("CPATH")
     remove "LDFLAGS", "-L#{HOMEBREW_PREFIX}/lib"
 
-    if (sdk = MacOS.sdk_path(version)) && !MacOS::CLT.installed?
-      delete("SDKROOT")
-      remove_from_cflags "-isysroot #{sdk}"
-      remove "CPPFLAGS", "-isysroot #{sdk}"
-      remove "LDFLAGS", "-isysroot #{sdk}"
-      if HOMEBREW_PREFIX.to_s == "/usr/local"
-        delete("CMAKE_PREFIX_PATH")
-      else
-        # It was set in setup_build_environment, so we have to restore it here.
-        self["CMAKE_PREFIX_PATH"] = HOMEBREW_PREFIX.to_s
-      end
-      remove "CMAKE_FRAMEWORK_PATH", "#{sdk}/System/Library/Frameworks"
+    return unless (sdk = MacOS.sdk_path(version)) && !MacOS::CLT.installed?
+    delete("SDKROOT")
+    remove_from_cflags "-isysroot #{sdk}"
+    remove "CPPFLAGS", "-isysroot #{sdk}"
+    remove "LDFLAGS", "-isysroot #{sdk}"
+    if HOMEBREW_PREFIX.to_s == "/usr/local"
+      delete("CMAKE_PREFIX_PATH")
+    else
+      # It was set in setup_build_environment, so we have to restore it here.
+      self["CMAKE_PREFIX_PATH"] = HOMEBREW_PREFIX.to_s
     end
+    remove "CMAKE_FRAMEWORK_PATH", "#{sdk}/System/Library/Frameworks"
   end
 
   def macosxsdk(version = MacOS.version)
@@ -89,20 +87,19 @@ module Stdenv
     self["CPATH"] = "#{HOMEBREW_PREFIX}/include"
     prepend "LDFLAGS", "-L#{HOMEBREW_PREFIX}/lib"
 
-    if (sdk = MacOS.sdk_path(version)) && !MacOS::CLT.installed?
-      # Extra setup to support Xcode 4.3+ without CLT.
-      self["SDKROOT"] = sdk
-      # Tell clang/gcc where system include's are:
-      append_path "CPATH", "#{sdk}/usr/include"
-      # The -isysroot is needed, too, because of the Frameworks
-      append_to_cflags "-isysroot #{sdk}"
-      append "CPPFLAGS", "-isysroot #{sdk}"
-      # And the linker needs to find sdk/usr/lib
-      append "LDFLAGS", "-isysroot #{sdk}"
-      # Needed to build cmake itself and perhaps some cmake projects:
-      append_path "CMAKE_PREFIX_PATH", "#{sdk}/usr"
-      append_path "CMAKE_FRAMEWORK_PATH", "#{sdk}/System/Library/Frameworks"
-    end
+    return unless (sdk = MacOS.sdk_path(version)) && !MacOS::CLT.installed?
+    # Extra setup to support Xcode 4.3+ without CLT.
+    self["SDKROOT"] = sdk
+    # Tell clang/gcc where system include's are:
+    append_path "CPATH", "#{sdk}/usr/include"
+    # The -isysroot is needed, too, because of the Frameworks
+    append_to_cflags "-isysroot #{sdk}"
+    append "CPPFLAGS", "-isysroot #{sdk}"
+    # And the linker needs to find sdk/usr/lib
+    append "LDFLAGS", "-isysroot #{sdk}"
+    # Needed to build cmake itself and perhaps some cmake projects:
+    append_path "CMAKE_PREFIX_PATH", "#{sdk}/usr"
+    append_path "CMAKE_FRAMEWORK_PATH", "#{sdk}/System/Library/Frameworks"
   end
 
   # Some configure scripts won't find libxml2 without help
diff --git a/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb b/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
index b3f8250ee..8bc42ad35 100644
--- a/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
+++ b/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
@@ -64,13 +64,12 @@ module FormulaCellarChecks
     keg = Keg.new(formula.prefix)
     checker = LinkageChecker.new(keg, formula)
 
-    if checker.broken_dylibs?
-      audit_check_output <<-EOS.undent
-        The installation was broken.
-        Broken dylib links found:
-          #{checker.broken_dylibs.to_a * "\n          "}
-      EOS
-    end
+    return unless checker.broken_dylibs?
+    audit_check_output <<-EOS.undent
+      The installation was broken.
+      Broken dylib links found:
+        #{checker.broken_dylibs.to_a * "\n          "}
+    EOS
   end
 
   def audit_installed
diff --git a/Library/Homebrew/extend/os/mac/utils/bottles.rb b/Library/Homebrew/extend/os/mac/utils/bottles.rb
index accfc6a59..0dd7341ea 100644
--- a/Library/Homebrew/extend/os/mac/utils/bottles.rb
+++ b/Library/Homebrew/extend/os/mac/utils/bottles.rb
@@ -31,10 +31,9 @@ module Utils
       # sometimes a formula has just :tiger_altivec, other times it has
       # :tiger_g4, :tiger_g5, etc.
       def find_altivec_tag(tag)
-        if tag.to_s =~ /(\w+)_(g4|g4e|g5)$/
-          altivec_tag = "#{$1}_altivec".to_sym
-          altivec_tag if key?(altivec_tag)
-        end
+        return unless tag.to_s =~ /(\w+)_(g4|g4e|g5)$/
+        altivec_tag = "#{$1}_altivec".to_sym
+        altivec_tag if key?(altivec_tag)
       end
 
       # Allows a bottle tag to specify a specific OS or later,
diff --git a/Library/Homebrew/extend/string.rb b/Library/Homebrew/extend/string.rb
index bd5994fe1..162666d2d 100644
--- a/Library/Homebrew/extend/string.rb
+++ b/Library/Homebrew/extend/string.rb
@@ -59,9 +59,8 @@ module StringInreplaceExtension
   # Looks for Makefile style variable defintions and replaces the
   # value with "new_value", or removes the definition entirely.
   def change_make_var!(flag, new_value)
-    unless gsub!(/^#{Regexp.escape(flag)}[ \t]*=[ \t]*(.*)$/, "#{flag}=#{new_value}", false)
-      errors << "expected to change #{flag.inspect} to #{new_value.inspect}"
-    end
+    return if gsub!(/^#{Regexp.escape(flag)}[ \t]*=[ \t]*(.*)$/, "#{flag}=#{new_value}", false)
+    errors << "expected to change #{flag.inspect} to #{new_value.inspect}"
   end
 
   # Removes variable assignments completely.
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index b9deb3a67..78dbc6940 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -224,10 +224,9 @@ class Formula
 
   def set_spec(name)
     spec = self.class.send(name)
-    if spec.url
-      spec.owner = self
-      instance_variable_set("@#{name}", spec)
-    end
+    return unless spec.url
+    spec.owner = self
+    instance_variable_set("@#{name}", spec)
   end
 
   def determine_active_spec(requested)
@@ -246,9 +245,8 @@ class Formula
     end
 
     val = version.respond_to?(:to_str) ? version.to_str : version
-    if val.nil? || val.empty? || val =~ /\s/
-      raise FormulaValidationError.new(full_name, :version, val)
-    end
+    return unless val.nil? || val.empty? || val =~ /\s/
+    raise FormulaValidationError.new(full_name, :version, val)
   end
 
   public
@@ -1065,10 +1063,9 @@ class Formula
 
   # @private
   def patch
-    unless patchlist.empty?
-      ohai "Patching"
-      patchlist.each(&:apply)
-    end
+    return if patchlist.empty?
+    ohai "Patching"
+    patchlist.each(&:apply)
   end
 
   # yields |self,staging| with current working directory set to the uncompressed tarball
@@ -1094,10 +1091,11 @@ class Formula
   def lock
     @lock = FormulaLock.new(name)
     @lock.lock
-    if oldname && (oldname_rack = HOMEBREW_CELLAR/oldname).exist? && oldname_rack.resolved_path == rack
-      @oldname_lock = FormulaLock.new(oldname)
-      @oldname_lock.lock
-    end
+    return unless oldname
+    return unless (oldname_rack = HOMEBREW_CELLAR/oldname).exist?
+    return unless oldname_rack.resolved_path == rack
+    @oldname_lock = FormulaLock.new(oldname)
+    @oldname_lock.lock
   end
 
   # @private
@@ -1427,10 +1425,9 @@ class Formula
 
   # @private
   def print_tap_action(options = {})
-    if tap?
-      verb = options[:verb] || "Installing"
-      ohai "#{verb} #{name} from #{tap}"
-    end
+    return unless tap?
+    verb = options[:verb] || "Installing"
+    ohai "#{verb} #{name} from #{tap}"
   end
 
   # @private
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 6e8f2e3b7..3738c3784 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -133,12 +133,10 @@ class FormulaInstaller
     begin
       compute_dependencies
     rescue TapFormulaUnavailableError => e
-      if e.tap.installed?
-        raise
-      else
-        e.tap.install
-        retry
-      end
+      raise if e.tap.installed?
+
+      e.tap.install
+      retry
     end
   rescue FormulaUnavailableError => e
     e.dependent = formula.full_name
@@ -148,23 +146,24 @@ class FormulaInstaller
   def check_install_sanity
     raise FormulaInstallationAlreadyAttemptedError, formula if @@attempted.include?(formula)
 
-    unless skip_deps_check?
-      recursive_deps = formula.recursive_dependencies
-      unlinked_deps = recursive_deps.map(&:to_formula).select do |dep|
-        dep.installed? && !dep.keg_only? && !dep.linked_keg.directory?
-      end
-      raise CannotInstallFormulaError,
-        "You must `brew link #{unlinked_deps*" "}` before #{formula.full_name} can be installed" unless unlinked_deps.empty?
+    return if skip_deps_check?
 
-      pinned_unsatisfied_deps = recursive_deps.select do |dep|
-        dep.to_formula.pinned? && !dep.satisfied?(inherited_options_for(dep))
-      end
+    recursive_deps = formula.recursive_dependencies
+    unlinked_deps = recursive_deps.map(&:to_formula).select do |dep|
+      dep.installed? && !dep.keg_only? && !dep.linked_keg.directory?
+    end
 
-      unless pinned_unsatisfied_deps.empty?
-        raise CannotInstallFormulaError,
-          "You must `brew unpin #{pinned_unsatisfied_deps*" "}` as installing #{formula.full_name} requires the latest version of pinned dependencies"
-      end
+    unless unlinked_deps.empty?
+      raise CannotInstallFormulaError, "You must `brew link #{unlinked_deps*" "}` before #{formula.full_name} can be installed"
+    end
+
+    pinned_unsatisfied_deps = recursive_deps.select do |dep|
+      dep.to_formula.pinned? && !dep.satisfied?(inherited_options_for(dep))
     end
+
+    return if pinned_unsatisfied_deps.empty?
+    raise CannotInstallFormulaError,
+      "You must `brew unpin #{pinned_unsatisfied_deps*" "}` as installing #{formula.full_name} requires the latest version of pinned dependencies"
   end
 
   def build_bottle_preinstall
@@ -285,11 +284,10 @@ class FormulaInstaller
           #{formula}: #{e.message}
           'conflicts_with \"#{c.name}\"' should be removed from #{formula.path.basename}.
         EOS
-        if ARGV.homebrew_developer?
-          raise
-        else
-          $stderr.puts "Please report this to the #{formula.tap} tap!"
-        end
+
+        raise if ARGV.homebrew_developer?
+
+        $stderr.puts "Please report this to the #{formula.tap} tap!"
         false
       else
         f.linked_keg.exist? && f.opt_prefix.exist?
@@ -492,10 +490,9 @@ class FormulaInstaller
 
     c = Caveats.new(formula)
 
-    unless c.empty?
-      @show_summary_heading = true
-      ohai "Caveats", c.caveats
-    end
+    return if c.empty?
+    @show_summary_heading = true
+    ohai "Caveats", c.caveats
   end
 
   def finish
@@ -706,13 +703,12 @@ class FormulaInstaller
       raise
     end
 
-    unless link_overwrite_backup.empty?
-      opoo "These files were overwritten during `brew link` step:"
-      puts link_overwrite_backup.keys
-      puts
-      puts "They have been backed up in #{backup_dir}"
-      @show_summary_heading = true
-    end
+    return if link_overwrite_backup.empty?
+    opoo "These files were overwritten during `brew link` step:"
+    puts link_overwrite_backup.keys
+    puts
+    puts "They have been backed up in #{backup_dir}"
+    @show_summary_heading = true
   end
 
   def install_plist
@@ -804,10 +800,9 @@ class FormulaInstaller
   end
 
   def audit_check_output(output)
-    if output
-      opoo output
-      @show_summary_heading = true
-    end
+    return unless output
+    opoo output
+    @show_summary_heading = true
   end
 
   def audit_installed
@@ -823,22 +818,20 @@ class FormulaInstaller
   end
 
   def lock
-    if (@@locked ||= []).empty?
-      formula.recursive_dependencies.each do |dep|
-        @@locked << dep.to_formula
-      end unless ignore_deps?
-      @@locked.unshift(formula)
-      @@locked.uniq!
-      @@locked.each(&:lock)
-      @hold_locks = true
-    end
+    return unless (@@locked ||= []).empty?
+    formula.recursive_dependencies.each do |dep|
+      @@locked << dep.to_formula
+    end unless ignore_deps?
+    @@locked.unshift(formula)
+    @@locked.uniq!
+    @@locked.each(&:lock)
+    @hold_locks = true
   end
 
   def unlock
-    if hold_locks?
-      @@locked.each(&:unlock)
-      @@locked.clear
-      @hold_locks = false
-    end
+    return unless hold_locks?
+    @@locked.each(&:unlock)
+    @@locked.clear
+    @hold_locks = false
   end
 end
diff --git a/Library/Homebrew/formula_lock.rb b/Library/Homebrew/formula_lock.rb
index 8743eaef8..4bd12df18 100644
--- a/Library/Homebrew/formula_lock.rb
+++ b/Library/Homebrew/formula_lock.rb
@@ -10,16 +10,14 @@ class FormulaLock
   def lock
     HOMEBREW_LOCK_DIR.mkpath
     @lockfile = get_or_create_lockfile
-    unless @lockfile.flock(File::LOCK_EX | File::LOCK_NB)
-      raise OperationInProgressError, @name
-    end
+    return if @lockfile.flock(File::LOCK_EX | File::LOCK_NB)
+    raise OperationInProgressError, @name
   end
 
   def unlock
-    unless @lockfile.nil? || @lockfile.closed?
-      @lockfile.flock(File::LOCK_UN)
-      @lockfile.close
-    end
+    return if @lockfile.nil? || @lockfile.closed?
+    @lockfile.flock(File::LOCK_UN)
+    @lockfile.close
   end
 
   def with_lock
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index a6ec45d3c..e3c893fd6 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -314,7 +314,9 @@ class Formulary
     possible_tap_formulae = tap_paths(ref)
     if possible_tap_formulae.size > 1
       raise TapFormulaAmbiguityError.new(ref, possible_tap_formulae)
-    elsif possible_tap_formulae.size == 1
+    end
+
+    if possible_tap_formulae.size == 1
       path = possible_tap_formulae.first.resolved_path
       name = path.basename(".rb").to_s
       return FormulaLoader.new(name, path)
@@ -336,7 +338,9 @@ class Formulary
 
     if possible_tap_newname_formulae.size > 1
       raise TapFormulaWithOldnameAmbiguityError.new(ref, possible_tap_newname_formulae)
-    elsif !possible_tap_newname_formulae.empty?
+    end
+
+    unless possible_tap_newname_formulae.empty?
       return TapLoader.new(possible_tap_newname_formulae.first)
     end
 
@@ -368,7 +372,9 @@ class Formulary
     possible_pinned_tap_formulae = tap_paths(ref, Dir["#{HOMEBREW_LIBRARY}/PinnedTaps/*/*/"]).map(&:realpath)
     if possible_pinned_tap_formulae.size > 1
       raise TapFormulaAmbiguityError.new(ref, possible_pinned_tap_formulae)
-    elsif possible_pinned_tap_formulae.size == 1
+    end
+
+    if possible_pinned_tap_formulae.size == 1
       selected_formula = factory(possible_pinned_tap_formulae.first, spec)
       if core_path(ref).file?
         opoo <<-EOS.undent
diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index ac31343d0..d2c9e12e8 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -394,10 +394,9 @@ class Keg
     opt_record.delete if opt_record.symlink? || opt_record.exist?
     make_relative_symlink(opt_record, path, mode)
 
-    if oldname_opt_record
-      oldname_opt_record.delete
-      make_relative_symlink(oldname_opt_record, path, mode)
-    end
+    return unless oldname_opt_record
+    oldname_opt_record.delete
+    make_relative_symlink(oldname_opt_record, path, mode)
   end
 
   def delete_pyc_files!
@@ -423,18 +422,19 @@ class Keg
       return
     end
 
-    if stat.directory?
-      begin
-        keg = Keg.for(src)
-      rescue NotAKegError
-        puts "Won't resolve conflicts for symlink #{dst} as it doesn't resolve into the Cellar" if ARGV.verbose?
-        return
+    return unless stat.directory?
+    begin
+      keg = Keg.for(src)
+    rescue NotAKegError
+      if ARGV.verbose?
+        puts "Won't resolve conflicts for symlink #{dst} as it doesn't resolve into the Cellar"
       end
-
-      dst.unlink unless mode.dry_run
-      keg.link_dir(src, mode) { :mkpath }
-      return true
+      return
     end
+
+    dst.unlink unless mode.dry_run
+    keg.link_dir(src, mode) { :mkpath }
+    true
   end
 
   def make_relative_symlink(dst, src, mode)
@@ -462,9 +462,8 @@ class Keg
     dst.delete if mode.overwrite && (dst.exist? || dst.symlink?)
     dst.make_relative_symlink(src)
   rescue Errno::EEXIST => e
-    if dst.exist?
-      raise ConflictError.new(self, src.relative_path_from(path), dst, e)
-    elsif dst.symlink?
+    raise ConflictError.new(self, src.relative_path_from(path), dst, e) if dst.exist?
+    if dst.symlink?
       dst.unlink
       retry
     end
diff --git a/Library/Homebrew/migrator.rb b/Library/Homebrew/migrator.rb
index d8c06de1a..addd97c8a 100644
--- a/Library/Homebrew/migrator.rb
+++ b/Library/Homebrew/migrator.rb
@@ -182,22 +182,21 @@ class Migrator
   end
 
   def repin
-    if pinned?
-      # old_pin_record is a relative symlink and when we try to to read it
-      # from <dir> we actually try to find file
-      # <dir>/../<...>/../Cellar/name/version.
-      # To repin formula we need to update the link thus that it points to
-      # the right directory.
-      # NOTE: old_pin_record.realpath.sub(oldname, newname) is unacceptable
-      # here, because it resolves every symlink for old_pin_record and then
-      # substitutes oldname with newname. It breaks things like
-      # Pathname#make_relative_symlink, where Pathname#relative_path_from
-      # is used to find relative path from source to destination parent and
-      # it assumes no symlinks.
-      src_oldname = old_pin_record.dirname.join(old_pin_link_record).expand_path
-      new_pin_record.make_relative_symlink(src_oldname.sub(oldname, newname))
-      old_pin_record.delete
-    end
+    return unless pinned?
+    # old_pin_record is a relative symlink and when we try to to read it
+    # from <dir> we actually try to find file
+    # <dir>/../<...>/../Cellar/name/version.
+    # To repin formula we need to update the link thus that it points to
+    # the right directory.
+    # NOTE: old_pin_record.realpath.sub(oldname, newname) is unacceptable
+    # here, because it resolves every symlink for old_pin_record and then
+    # substitutes oldname with newname. It breaks things like
+    # Pathname#make_relative_symlink, where Pathname#relative_path_from
+    # is used to find relative path from source to destination parent and
+    # it assumes no symlinks.
+    src_oldname = old_pin_record.dirname.join(old_pin_link_record).expand_path
+    new_pin_record.make_relative_symlink(src_oldname.sub(oldname, newname))
+    old_pin_record.delete
   end
 
   def unlink_oldname
@@ -254,10 +253,9 @@ class Migrator
 
   # Link keg to opt if it was linked before migrating.
   def link_oldname_opt
-    if old_opt_record
-      old_opt_record.delete if old_opt_record.symlink?
-      old_opt_record.make_relative_symlink(new_linked_keg_record)
-    end
+    return unless old_opt_record
+    old_opt_record.delete if old_opt_record.symlink?
+    old_opt_record.make_relative_symlink(new_linked_keg_record)
   end
 
   # After migtaion every INSTALL_RECEIPT.json has wrong path to the formula
@@ -316,23 +314,22 @@ class Migrator
       end
     end
 
-    unless old_linked_keg.nil?
-      # The keg used to be linked and when we backup everything we restore
-      # Cellar/oldname, the target also gets restored, so we are able to
-      # create a keg using its old path
-      if old_linked_keg_record
-        begin
-          old_linked_keg.link
-        rescue Keg::LinkError
-          old_linked_keg.unlink
-          raise
-        rescue Keg::AlreadyLinkedError
-          old_linked_keg.unlink
-          retry
-        end
-      else
-        old_linked_keg.optlink
+    return if old_linked_keg.nil?
+    # The keg used to be linked and when we backup everything we restore
+    # Cellar/oldname, the target also gets restored, so we are able to
+    # create a keg using its old path
+    if old_linked_keg_record
+      begin
+        old_linked_keg.link
+      rescue Keg::LinkError
+        old_linked_keg.unlink
+        raise
+      rescue Keg::AlreadyLinkedError
+        old_linked_keg.unlink
+        retry
       end
+    else
+      old_linked_keg.optlink
     end
   end
 
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index dac8b8f1e..0f78e4412 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -18,12 +18,10 @@ module OS
         when "10.11" then "8.0"
         when "10.12" then "8.0"
         else
+          raise "macOS '#{MacOS.version}' is invalid" unless OS::Mac.prerelease?
+
           # Default to newest known version of Xcode for unreleased macOS versions.
-          if OS::Mac.prerelease?
-            "8.0"
-          else
-            raise "macOS '#{MacOS.version}' is invalid"
-          end
+          "8.0"
         end
       end
 
diff --git a/Library/Homebrew/patch.rb b/Library/Homebrew/patch.rb
index 74e58e526..1b7751ba3 100644
--- a/Library/Homebrew/patch.rb
+++ b/Library/Homebrew/patch.rb
@@ -130,14 +130,13 @@ class ExternalPatch
       patch_dir = Pathname.pwd
       if patch_files.empty?
         children = patch_dir.children
-        if children.length == 1 && children.first.file?
-          patch_files << children.first.basename
-        else
+        if children.length != 1 || !children.first.file?
           raise MissingApplyError, <<-EOS.undent
             There should be exactly one patch file in the staging directory unless
             the "apply" method was used one or more times in the patch-do block.
           EOS
         end
+        patch_files << children.first.basename
       end
       dir.cd do
         patch_files.each do |patch_file|
diff --git a/Library/Homebrew/requirement.rb b/Library/Homebrew/requirement.rb
index 2931b1466..89487fec3 100644
--- a/Library/Homebrew/requirement.rb
+++ b/Library/Homebrew/requirement.rb
@@ -83,12 +83,11 @@ class Requirement
     # PATH.
     # This is undocumented magic and it should be removed, but we need to add
     # a way to declare path-based requirements that work with superenv first.
-    if @satisfied_result.is_a?(Pathname)
-      parent = @satisfied_result.parent
-      unless ENV["PATH"].split(File::PATH_SEPARATOR).include?(parent.to_s)
-        ENV.append_path("PATH", parent)
-      end
-    end
+    return unless @satisfied_result.is_a?(Pathname)
+    parent = @satisfied_result.parent
+
+    return if ENV["PATH"].split(File::PATH_SEPARATOR).include?(parent.to_s)
+    ENV.append_path("PATH", parent)
   end
 
   def env
@@ -199,11 +198,8 @@ class Requirement
 
       formulae.each do |f|
         f.requirements.each do |req|
-          if prune?(f, req, &block)
-            next
-          else
-            reqs << req
-          end
+          next if prune?(f, req, &block)
+          reqs << req
         end
       end
 
diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index ecf81ca37..c73e3f7a7 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -130,9 +130,8 @@ class Tap
   # The issues URL of this {Tap}.
   # e.g. `https://github.com/user/homebrew-repo/issues`
   def issues_url
-    if official? || !custom_remote?
-      "https://github.com/#{user}/homebrew-#{repo}/issues"
-    end
+    return unless official? || !custom_remote?
+    "https://github.com/#{user}/homebrew-#{repo}/issues"
   end
 
   def to_s
@@ -236,15 +235,16 @@ class Tap
     puts "Tapped #{formula_count} formula#{plural(formula_count, "e")} (#{path.abv})" unless quiet
     Descriptions.cache_formulae(formula_names)
 
-    if !options[:clone_target] && private? && !quiet
-      puts <<-EOS.undent
-        It looks like you tapped a private repository. To avoid entering your
-        credentials each time you update, you can use git HTTP credential
-        caching or issue the following command:
-          cd #{path}
-          git remote set-url origin git@github.com:#{user}/homebrew-#{repo}.git
-      EOS
-    end
+    return if options[:clone_target]
+    return unless private?
+    return if quiet
+    puts <<-EOS.undent
+      It looks like you tapped a private repository. To avoid entering your
+      credentials each time you update, you can use git HTTP credential
+      caching or issue the following command:
+        cd #{path}
+        git remote set-url origin git@github.com:#{user}/homebrew-#{repo}.git
+    EOS
   end
 
   def link_manpages
diff --git a/Library/Homebrew/test/test_cmd_testbot.rb b/Library/Homebrew/test/test_cmd_testbot.rb
index d762448d1..239fa7a37 100644
--- a/Library/Homebrew/test/test_cmd_testbot.rb
+++ b/Library/Homebrew/test/test_cmd_testbot.rb
@@ -45,9 +45,8 @@ class TestbotStepTests < Homebrew::TestCase
   end
 
   def teardown
-    unless passed?
-      raise "INFO: Previous test failed with ENV['TRAVIS'] = #{ENV["TRAVIS"].inspect}"
-    end
+    return if passed?
+    raise "INFO: Previous test failed with ENV['TRAVIS'] = #{ENV["TRAVIS"].inspect}"
   end
 
   def stub_test_instance
diff --git a/Library/Homebrew/test/test_integration_cmds.rb b/Library/Homebrew/test/test_integration_cmds.rb
index 11eb6c69d..379e8d90d 100644
--- a/Library/Homebrew/test/test_integration_cmds.rb
+++ b/Library/Homebrew/test/test_integration_cmds.rb
@@ -39,9 +39,8 @@ class IntegrationCommandTests < Homebrew::TestCase
   end
 
   def needs_test_cmd_taps
-    unless ENV["HOMEBREW_TEST_OFFICIAL_CMD_TAPS"]
-      skip "HOMEBREW_TEST_OFFICIAL_CMD_TAPS is not set"
-    end
+    return if ENV["HOMEBREW_TEST_OFFICIAL_CMD_TAPS"]
+    skip "HOMEBREW_TEST_OFFICIAL_CMD_TAPS is not set"
   end
 
   def needs_macos
diff --git a/Library/Homebrew/test/testing_env.rb b/Library/Homebrew/test/testing_env.rb
index 2b4f9422b..02264aa39 100644
--- a/Library/Homebrew/test/testing_env.rb
+++ b/Library/Homebrew/test/testing_env.rb
@@ -57,9 +57,8 @@ module Homebrew
       super
       files_after_test = []
       Find.find(TEST_TMPDIR) { |f| files_after_test << f.sub(TEST_TMPDIR, "") }
-      if @__files_before_test != files_after_test
-        @@log.puts location, diff(@__files_before_test, files_after_test)
-      end
+      return if @__files_before_test == files_after_test
+      @@log.puts location, diff(@__files_before_test, files_after_test)
     end
   end
 
diff --git a/Library/Homebrew/utils.rb b/Library/Homebrew/utils.rb
index be629f1df..58083fe1b 100644
--- a/Library/Homebrew/utils.rb
+++ b/Library/Homebrew/utils.rb
@@ -218,13 +218,9 @@ def interactive_shell(f = nil)
 
   Process.wait fork { exec ENV["SHELL"] }
 
-  if $?.success?
-    return
-  elsif $?.exited?
-    raise "Aborted due to non-zero exit status (#{$?.exitstatus})"
-  else
-    raise $?.inspect
-  end
+  return if $?.success?
+  raise "Aborted due to non-zero exit status (#{$?.exitstatus})" if $?.exited?
+  raise $?.inspect
 end
 
 module Homebrew
@@ -325,13 +321,12 @@ module Homebrew
       end
     end
 
-    if $times.nil?
-      $times = {}
-      at_exit do
-        col_width = [$times.keys.map(&:size).max + 2, 15].max
-        $times.sort_by { |_k, v| v }.each do |method, time|
-          puts format("%-*s %0.4f sec", col_width, "#{method}:", time)
-        end
+    return unless $times.nil?
+    $times = {}
+    at_exit do
+      col_width = [$times.keys.map(&:size).max + 2, 15].max
+      $times.sort_by { |_k, v| v }.each do |method, time|
+        puts format("%-*s %0.4f sec", col_width, "#{method}:", time)
       end
     end
   end
@@ -608,14 +603,14 @@ def link_src_dst_dirs(src_dir, dst_dir, command, link_dir: false)
     dst_dir.parent.mkpath
     dst.make_relative_symlink(src)
   end
-  unless conflicts.empty?
-    onoe <<-EOS.undent
-      Could not link:
-      #{conflicts.join("\n")}
 
-      Please delete these paths and run `#{command}`.
-    EOS
-  end
+  return if conflicts.empty?
+  onoe <<-EOS.undent
+    Could not link:
+    #{conflicts.join("\n")}
+
+    Please delete these paths and run `#{command}`.
+  EOS
 end
 
 def link_path_manpages(path, command)
diff --git a/Library/Homebrew/utils/popen.rb b/Library/Homebrew/utils/popen.rb
index 76e67b3a9..350d9a09f 100644
--- a/Library/Homebrew/utils/popen.rb
+++ b/Library/Homebrew/utils/popen.rb
@@ -14,11 +14,8 @@ module Utils
   def self.popen(args, mode)
     IO.popen("-", mode) do |pipe|
       if pipe
-        if block_given?
-          yield pipe
-        else
-          return pipe.read
-        end
+        return pipe.read unless block_given?
+        yield pipe
       else
         $stderr.reopen("/dev/null", "w")
         exec(*args)
diff --git a/Library/Homebrew/version.rb b/Library/Homebrew/version.rb
index 60eb6b571..a1f482192 100644
--- a/Library/Homebrew/version.rb
+++ b/Library/Homebrew/version.rb
@@ -192,11 +192,10 @@ class Version
   end
 
   def initialize(val)
-    if val.respond_to?(:to_str)
-      @version = val.to_str
-    else
+    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?