[Rubocop] Fix SpecialGlobalVars

Rakefile

@@ -80,7 +80,7 @@ end
 desc 'Print the options of the various downloaders'
 task :print_options do
   title 'Downloaders options'
-  $:.unshift File.expand_path('../lib', __FILE__)
+  $LOAD_PATH.unshift File.expand_path('../lib', __FILE__)
   require 'cocoapods-downloader'
   include Pod::Downloader
 

examples/downloading_a_git_repo.rb

@@ -1,4 +1,4 @@
-$:.unshift(File.expand_path('../../lib', __FILE__))
+$LOAD_PATH.unshift(File.expand_path('../../lib', __FILE__))
 
 require 'cocoapods-downloader'
 

lib/cocoapods-downloader.rb

@@ -3,7 +3,7 @@ module Downloader
     if RUBY_VERSION >= '1.9.3'
       require 'English'
     else
-      alias $CHILD_STATUS $?
+      alias $CHILD_STATUS $CHILD_STATUS
     end
 
     require 'cocoapods-downloader/gem_version'

lib/cocoapods-downloader/api.rb

@@ -21,7 +21,7 @@ def execute_command(executable, command, raise_on_failure = false)
       # @return [void]
       #
       def check_exit_code!(executable, command, output)
-        if $?.to_i != 0
+        if $CHILD_STATUS.to_i != 0
           raise DownloaderError, "Error on `#{executable} #{command}`.\n#{output}"
         end
       end

lib/cocoapods-downloader/git.rb

@@ -143,7 +143,7 @@ def download_branch
       def ref_exists?(ref)
         if cache_exist?
           Dir.chdir(cache_path) { git "rev-list --max-count=1 #{ref}" }
-          $? == 0
+          $CHILD_STATUS == 0
         else
           false
         end
@@ -164,7 +164,7 @@ def ensure_ref_exists(ref)
       #
       def branch_exists?(branch)
         Dir.chdir(cache_path) { git "branch --all | grep #{branch}$" } # check for remote branch and do suffix matching ($ anchor)
-        $? == 0
+        $CHILD_STATUS == 0
       end
 
       # @return [void] Checks if a branch exists in the cache and updates
@@ -175,7 +175,7 @@ def branch_exists?(branch)
       def ensure_remote_branch_exists(branch)
         return if branch_exists?(branch)
         update_cache
-        raise DownloaderError, "Cache unable to find git reference `#{branch}' for `#{url}' (#{$?})." unless branch_exists?(branch)
+        raise DownloaderError, "Cache unable to find git reference `#{branch}' for `#{url}' (#{$CHILD_STATUS})." unless branch_exists?(branch)
       end
 
       #--------------------------------------#

rubocop-todo.yml

@@ -23,8 +23,6 @@ RaiseArgs:
   Enabled: false
 RegexpLiteral:
   Enabled: false
-SpecialGlobalVars:
-  Enabled: false
 TrailingComma:
   Enabled: false
 UnusedMethodArgument:

spec/spec_helper.rb

@@ -20,7 +20,7 @@
 require 'vcr'
 require 'webmock'
 
-$:.unshift File.expand_path('../../lib', __FILE__)
+$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
 require 'cocoapods-downloader'
 
 #-- Output suppression -------------------------------------------------------#