diff --git a/Library/Homebrew/Gemfile.lock b/Library/Homebrew/Gemfile.lock
index 11584197bc..2a6303a20a 100644
--- a/Library/Homebrew/Gemfile.lock
+++ b/Library/Homebrew/Gemfile.lock
@@ -54,7 +54,6 @@ GEM
     parser (2.6.0.0)
       ast (~> 2.4.0)
     plist (3.5.0)
-    powerpack (0.1.2)
     psych (3.1.0)
     rainbow (3.0.0)
     rdiscount (2.2.0.1)
@@ -82,15 +81,14 @@ GEM
     rspec-support (3.8.0)
     rspec-wait (0.0.9)
       rspec (>= 3, < 4)
-    rubocop (0.65.0)
+    rubocop (0.66.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
       parser (>= 2.5, != 2.5.1.1)
-      powerpack (~> 0.1)
       psych (>= 3.1.0)
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (~> 1.4.0)
+      unicode-display_width (>= 1.4.0, < 1.6)
     rubocop-rspec (1.32.0)
       rubocop (>= 0.60.0)
     ruby-macho (2.2.0)
@@ -112,7 +110,7 @@ GEM
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.5)
-    unicode-display_width (1.4.1)
+    unicode-display_width (1.5.0)
     webrobots (0.1.2)
 
 PLATFORMS
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index dc967d623d..f7be8eb219 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -511,7 +511,7 @@ module Homebrew
       end
 
       def check_git_version
-        minimum_version = ENV["HOMEBREW_MINIMUM_GIT_VERSION"].freeze
+        minimum_version = ENV["HOMEBREW_MINIMUM_GIT_VERSION"]
         return unless Utils.git_available?
         return if Version.create(Utils.git_version) >= Version.create(minimum_version)
 
diff --git a/Library/Homebrew/exceptions.rb b/Library/Homebrew/exceptions.rb
index 183551578c..7e47382b58 100644
--- a/Library/Homebrew/exceptions.rb
+++ b/Library/Homebrew/exceptions.rb
@@ -419,7 +419,7 @@ class BuildError < RuntimeError
 
     puts
 
-    unless issues&.empty?
+    if issues.present?
       puts "These open issues may also help:"
       puts issues.map { |i| "#{i["title"]} #{i["html_url"]}" }.join("\n")
     end
diff --git a/Library/Homebrew/tab.rb b/Library/Homebrew/tab.rb
index 7a58ed6e2c..28c3e6594f 100644
--- a/Library/Homebrew/tab.rb
+++ b/Library/Homebrew/tab.rb
@@ -324,7 +324,7 @@ class Tab < OpenStruct
     Time.at(super)
   end
 
-  def to_json
+  def to_json(options = nil)
     attributes = {
       "homebrew_version"        => homebrew_version,
       "used_options"            => used_options.as_flags,
@@ -344,7 +344,7 @@ class Tab < OpenStruct
       "source"                  => source,
     }
 
-    JSON.generate(attributes)
+    JSON.generate(attributes, options)
   end
 
   def write
diff --git a/Library/Homebrew/vendor/bundle/bundler/setup.rb b/Library/Homebrew/vendor/bundle/bundler/setup.rb
index 90bd8cff1d..5f66e21917 100644
--- a/Library/Homebrew/vendor/bundle/bundler/setup.rb
+++ b/Library/Homebrew/vendor/bundle/bundler/setup.rb
@@ -47,7 +47,6 @@ $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parallel-1.14.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parallel_tests-2.28.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/parser-2.6.0.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/plist-3.5.0/lib"
-$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/powerpack-0.1.2/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/extensions/universal-darwin-18/2.3.0/psych-3.1.0"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/psych-3.1.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rainbow-3.0.0/lib"
@@ -63,8 +62,8 @@ $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rspec-its-1.2.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rspec-retry-0.6.1/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rspec-wait-0.0.9/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/ruby-progressbar-1.10.0/lib"
-$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/unicode-display_width-1.4.1/lib"
-$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rubocop-0.65.0/lib"
+$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/unicode-display_width-1.5.0/lib"
+$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rubocop-0.66.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/rubocop-rspec-1.32.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/ruby-macho-2.2.0/lib"
 $:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/simplecov-cobertura-1.3.0/lib"