Fixup more frozen string handling.

Library/Homebrew/cask/artifact/abstract_uninstall.rb

@@ -94,10 +94,10 @@ module Cask
               sleep 1
             end
             paths = [
-              "/Library/LaunchAgents/#{service}.plist",
+              +"/Library/LaunchAgents/#{service}.plist",
-              "/Library/LaunchDaemons/#{service}.plist",
+              +"/Library/LaunchDaemons/#{service}.plist",
             ]
-            paths.each { |elt| elt.prepend(ENV["HOME"]) } unless with_sudo
+            paths.each { |elt| elt.prepend(ENV["HOME"]).freeze } unless with_sudo
             paths = paths.map { |elt| Pathname(elt) }.select(&:exist?)
             paths.each do |path|
               command.run!("/bin/rm", args: ["-f", "--", path], sudo: with_sudo)

Library/Homebrew/cask/cmd/abstract_command.rb

@@ -61,8 +61,7 @@ module Cask
         if matches.one?
           "Did you mean “#{matches.first}”?"
         elsif !matches.empty?
-          "Did you mean one of these?\n"
+          "Did you mean one of these?\n#{Formatter.columns(matches.take(20))}"
-            .concat(Formatter.columns(matches.take(20)))
         end
       end
     end

Library/Homebrew/cask/cmd/edit.rb

@@ -12,9 +12,9 @@ module Cask
       def run
         exec_editor cask_path
       rescue CaskUnavailableError => e
-        reason = e.reason.empty? ? "" : "#{e.reason} "
+        reason = e.reason.empty? ? +"" : +"#{e.reason} "
         reason.concat("Run #{Formatter.identifier("brew cask create #{e.token}")} to create a new Cask.")
-        raise e.class.new(e.token, reason)
+        raise e.class.new(e.token, reason.freeze)
       end
 
       def cask_path

Library/Homebrew/cask/cmd/info.rb

@@ -106,14 +106,14 @@ module Cask
       end
 
       def self.artifact_info(cask)
-        artifact_output = ohai_title("Artifacts")
+        artifact_output = ohai_title("Artifacts").dup
         cask.artifacts.each do |artifact|
           next unless artifact.respond_to?(:install_phase)
           next unless DSL::ORDINARY_ARTIFACT_CLASSES.include?(artifact.class)
 
           artifact_output << "\n" << artifact.to_s
         end
-        artifact_output
+        artifact_output.freeze
       end
     end
   end

Library/Homebrew/cask/installer.rb

@@ -138,9 +138,10 @@ module Cask
     end
 
     def summary
-      s = ""
+      s = +""
       s << "#{Emoji.install_badge}  " if Emoji.enabled?
       s << "#{@cask} was successfully #{upgrade? ? "upgraded" : "installed"}!"
+      s.freeze
     end
 
     def download

Library/Homebrew/caveats.rb

@@ -42,7 +42,7 @@ class Caveats
         #{f.name} is keg-only, which means it was not symlinked into #{HOMEBREW_PREFIX},
         because #{f.keg_only_reason.to_s.chomp}.
       EOS
-    end
+    end.dup
 
     if f.bin.directory? || f.sbin.directory?
       s << <<~EOS
@@ -120,10 +120,10 @@ class Caveats
           #{root_dir}/share/zsh/site-functions
       EOS
     when :fish
-      fish_caveats = "fish #{installed.join(" and ")} have been installed to:"
+      fish_caveats = +"fish #{installed.join(" and ")} have been installed to:"
       fish_caveats << "\n  #{root_dir}/share/fish/vendor_completions.d" if completion_installed
       fish_caveats << "\n  #{root_dir}/share/fish/vendor_functions.d" if functions_installed
-      fish_caveats
+      fish_caveats.freeze
     end
   end
 

Library/Homebrew/dev-cmd/bottle.rb

@@ -1,4 +1,6 @@
-# frozen_string_literal: true
+# Uses ERB so can't use Frozen String Literals until >=Ruby 2.4:
+# https://bugs.ruby-lang.org/issues/12031
+# frozen_string_literal: false
 
 require "formula"
 require "utils/bottles"
@@ -9,7 +11,7 @@ require "cli/parser"
 require "utils/inreplace"
 require "erb"
 
-BOTTLE_ERB = <<-EOS
+BOTTLE_ERB = <<-EOS.freeze
   bottle do
     <% if  !["#{HOMEBREW_BOTTLE_DEFAULT_DOMAIN}/bottles", "https://homebrew.bintray.com/bottles"].include?(root_url) %>
     root_url "<%= root_url %>"
@@ -41,7 +43,7 @@ module Homebrew
 
   def bottle_args
     Homebrew::CLI::Parser.new do
-      usage_banner <<~EOS
+      usage_banner <<~EOS.freeze
         `bottle` [<options>] <formula>
 
         Generate a bottle (binary package) from a formula that was installed with
@@ -378,7 +380,7 @@ module Homebrew
           "#{key}: old: #{old_value}, new: #{value}"
         end
 
-        odie <<~EOS
+        odie <<~EOS.freeze
           --keep-old was passed but there are changes in:
           #{mismatches.join("\n")}
         EOS
@@ -489,7 +491,7 @@ module Homebrew
               end
 
               unless mismatches.empty?
-                odie <<~EOS
+                odie <<~EOS.freeze
                   --keep-old was passed but there are changes in:
                   #{mismatches.join("\n")}
                 EOS

Library/Homebrew/dev-cmd/man.rb

@@ -1,4 +1,6 @@
-# frozen_string_literal: true
+# Uses ERB so can't use Frozen String Literals until >=Ruby 2.4:
+# https://bugs.ruby-lang.org/issues/12031
+# frozen_string_literal: false
 
 require "formula"
 require "erb"
@@ -16,7 +18,7 @@ module Homebrew
 
   def man_args
     Homebrew::CLI::Parser.new do
-      usage_banner <<~EOS
+      usage_banner <<~EOS.freeze
         `man` [<options>]
 
         Generate Homebrew's manpages.

Library/Homebrew/diagnostic.rb

@@ -71,7 +71,8 @@ module Homebrew
       end
 
       def inject_file_list(list, string)
-        list.reduce(string) { |acc, elem| acc << "  #{elem}\n" }
+        list.reduce(string.dup) { |acc, elem| acc << "  #{elem}\n" }
+            .freeze
       end
       ############# END HELPERS
 

Library/Homebrew/exceptions.rb

@@ -531,7 +531,7 @@ class ErrorDuringExecution < RuntimeError
       status
     end
 
-    s = "Failure while executing; `#{cmd.shelljoin.gsub(/\\=/, "=")}` exited with #{exitstatus}."
+    s = +"Failure while executing; `#{cmd.shelljoin.gsub(/\\=/, "=")}` exited with #{exitstatus}."
 
     unless [*output].empty?
       format_output_line = lambda do |type_line|
@@ -548,7 +548,7 @@ class ErrorDuringExecution < RuntimeError
       s << "\n" unless s.end_with?("\n")
     end
 
-    super s
+    super s.freeze
   end
 
   def stderr

Library/Homebrew/formula_installer.rb

@@ -666,7 +666,7 @@ class FormulaInstaller
   end
 
   def summary
-    s = ""
+    s = +""
     s << "#{Emoji.install_badge}  " if Emoji.enabled?
     s << "#{formula.prefix.resolved_path}: #{formula.prefix.abv}"
     s << ", built in #{pretty_duration build_time}" if build_time

Library/Homebrew/missing_formula.rb

@@ -200,9 +200,9 @@ module Homebrew
         return if silent
 
         cask = Cask::CaskLoader.load(name)
-        reason = "Found a cask named \"#{name}\" instead.\n"
+        reason = +"Found a cask named \"#{name}\" instead.\n"
         reason << Cask::Cmd::Info.get_info(cask) if show_info
-        reason
+        reason.freeze
       rescue Cask::CaskUnavailableError
         nil
       end

Library/Homebrew/test/formula_spec.rb

@@ -382,7 +382,7 @@ describe Formula do
 
       stamps_with_revisions.each do |stamp, revision|
         version = "HEAD-#{stamp}"
-        version << "_#{revision}" unless revision.zero?
+        version = "#{version}_#{revision}" unless revision.zero?
 
         prefix = f.rack/version
         prefix.mkpath

Library/Homebrew/test/inreplace_spec.rb

@@ -5,7 +5,7 @@ require "tempfile"
 require "utils/inreplace"
 
 describe StringInreplaceExtension do
-  subject { string.extend(described_class) }
+  subject { string.dup.extend(described_class) }
 
   describe "#change_make_var!" do
     context "flag" do

Library/Homebrew/test/string_spec.rb

@@ -5,7 +5,7 @@ require "extend/string"
 describe StringInreplaceExtension do
   subject { string.extend(described_class) }
 
-  let(:string) { "foobar" }
+  let(:string) { +"foobar" }
 
   describe "#sub!" do
     it "adds an error to #errors when no replacement was made" do

Library/Homebrew/utils.rb

@@ -113,8 +113,9 @@ def odeprecated(method, replacement = nil, disable: false, disable_on: nil, call
     break
   end
 
-  message = "Calling #{method} is #{verb}! #{replacement_message}"
+  message = +"Calling #{method} is #{verb}! #{replacement_message}"
   message << tap_message if tap_message
+  message.freeze
 
   if ARGV.homebrew_developer? || disable || Homebrew.raise_deprecation_exceptions?
     exception = MethodDeprecatedError.new(message)
@@ -152,12 +153,12 @@ end
 
 def pretty_duration(s)
   s = s.to_i
-  res = ""
+  res = +""
 
   if s > 59
     m = s / 60
     s %= 60
-    res = "#{m} #{"minute".pluralize(m)}"
+    res = +"#{m} #{"minute".pluralize(m)}"
     return res.freeze if s.zero?
 
     res << " "

Library/Homebrew/utils/inreplace.rb

@@ -3,10 +3,10 @@
 module Utils
   class InreplaceError < RuntimeError
     def initialize(errors)
-      formatted_errors = errors.reduce("inreplace failed\n") do |s, (path, errs)|
+      formatted_errors = errors.reduce(+"inreplace failed\n") do |s, (path, errs)|
         s << "#{path}:\n" << errs.map { |e| "  #{e}\n" }.join
       end
-      super formatted_errors
+      super formatted_errors.freeze
     end
   end