Remove debugger support

bebugger doesn't work with Ruby 2.2 so we don't need to support it
anymore

Gemfile

@@ -68,8 +68,8 @@ group :test do
     gem 'stackprof'
   end
 
-  # platforms :mri_19, :mri_20 do
-  #   gem 'debugger'
+  # platforms :mri do
+  #   gem 'byebug'
   # end
 
   gem 'benchmark-ips'

activesupport/lib/active_support/core_ext/kernel.rb

 require 'active_support/core_ext/kernel/agnostics'
 require 'active_support/core_ext/kernel/concern'
-require 'active_support/core_ext/kernel/debugger' if RUBY_VERSION < '2.0.0'
 require 'active_support/core_ext/kernel/reporting'
 require 'active_support/core_ext/kernel/singleton_class'

activesupport/lib/active_support/core_ext/kernel/debugger.rb

-module Kernel
-  unless respond_to?(:debugger)
-    # Starts a debugging session if the +debugger+ gem has been loaded (call rails server --debugger to load it).
-    def debugger
-      message = "\n***** Debugger requested, but was not available (ensure the debugger gem is listed in Gemfile/installed as gem): Start server with --debugger to enable *****\n"
-      defined?(Rails.logger) ? Rails.logger.info(message) : $stderr.puts(message)
-    end
-    alias breakpoint debugger unless respond_to?(:breakpoint)
-  end
-end
+require 'active_support/deprecation'
+
+ActiveSupport::Deprecation.warn("This file is deprecated and will be removed in Rails 5.1 with no replacement.")

activesupport/test/core_ext/kernel_test.rb

@@ -65,27 +65,3 @@ def write(message)
     puts(message)
   end
 end
-
-class KernelDebuggerTest < ActiveSupport::TestCase
-  def test_debugger_not_available_message_to_stderr
-    old_stderr = $stderr
-    $stderr = MockStdErr.new
-    debugger
-    assert_match(/Debugger requested/, $stderr.output.first)
-  ensure
-    $stderr = old_stderr
-  end
-
-  def test_debugger_not_available_message_to_rails_logger
-    rails = Class.new do
-      def self.logger
-        @logger ||= MockStdErr.new
-      end
-    end
-    Object.const_set(:Rails, rails)
-    debugger
-    assert_match(/Debugger requested/, rails.logger.output.first)
-  ensure
-    Object.send(:remove_const, :Rails)
-  end
-end if RUBY_VERSION < '2.0.0'

guides/source/rails_on_rack.md

@@ -63,7 +63,6 @@ Here's how it loads the middlewares:
 ```ruby
 def middleware
   middlewares = []
-  middlewares << [Rails::Rack::Debugger] if options[:debugger]
   middlewares << [::Rack::ContentLength]
   Hash.new(middlewares)
 end

railties/lib/rails/commands/console.rb

@@ -18,14 +18,6 @@ def parse_arguments(arguments)
           opt.on("-e", "--environment=name", String,
                   "Specifies the environment to run this console under (test/development/production).",
                   "Default: development") { |v| options[:environment] = v.strip }
-          opt.on("--debugger", 'Enables the debugger.') do |v|
-            if RUBY_VERSION < '2.0.0'
-              options[:debugger] = v
-            else
-              puts "=> Notice: debugger option is ignored since Ruby 2.0 and " \
-                   "it will be removed in future versions."
-            end
-          end
           opt.parse!(arguments)
         end
 
@@ -76,25 +68,7 @@ def set_environment!
       Rails.env = environment
     end
 
-    if RUBY_VERSION < '2.0.0'
-      def debugger?
-        options[:debugger]
-      end
-
-      def require_debugger
-        require 'debugger'
-        puts "=> Debugger enabled"
-      rescue LoadError
-        puts "You're missing the 'debugger' gem. Add it to your Gemfile, bundle it and try again."
-        exit(1)
-      end
-    end
-
     def start
-      if RUBY_VERSION < '2.0.0'
-        require_debugger if debugger?
-      end
-
       set_environment! if environment?
 
       if sandbox?

railties/lib/rails/commands/server.rb

@@ -28,14 +28,6 @@ def option_parser(options)
           opts.on("-c", "--config=file", String,
                   "Uses a custom rackup configuration.") { |v| options[:config] = v }
           opts.on("-d", "--daemon", "Runs server as a Daemon.") { options[:daemonize] = true }
-          opts.on("-u", "--debugger", "Enables the debugger.") do
-            if RUBY_VERSION < '2.0.0'
-              options[:debugger] = true
-            else
-              puts "=> Notice: debugger option is ignored since Ruby 2.0 and " \
-                   "it will be removed in future versions."
-            end
-          end
           opts.on("-e", "--environment=name", String,
                   "Specifies the environment to run this server under (test/development/production).",
                   "Default: development") { |v| options[:environment] = v }
@@ -86,9 +78,6 @@ def start
 
     def middleware
       middlewares = []
-      if RUBY_VERSION < '2.0.0'
-        middlewares << [Rails::Rack::Debugger] if options[:debugger]
-      end
       middlewares << [::Rack::ContentLength]
 
       # FIXME: add Rack::Lock in the case people are using webrick.
@@ -112,7 +101,6 @@ def default_options
         DoNotReverseLookup: true,
         environment:        (ENV['RAILS_ENV'] || ENV['RACK_ENV'] || "development").dup,
         daemonize:          false,
-        debugger:           false,
         pid:                File.expand_path("tmp/pids/server.pid"),
         config:             File.expand_path("config.ru")
       })

railties/lib/rails/generators/rails/app/templates/Gemfile

@@ -23,13 +23,8 @@ source 'https://rubygems.org'
 
 group :development, :test do
 <% if RUBY_ENGINE == 'ruby' -%>
-  <%- if RUBY_VERSION < '2.0.0' -%>
-  # Call 'debugger' anywhere in the code to stop execution and get a debugger console
-  gem 'debugger'
-  <%- else -%>
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug'
-  <%- end -%>
 
   # Access an IRB console on exception pages or by using <%%= console %> in views
   <%- if options.dev? || options.edge? -%>

railties/lib/rails/generators/rails/plugin/templates/Gemfile

@@ -39,11 +39,7 @@ end
 <% end -%>
 <% if RUBY_ENGINE == 'ruby' -%>
 # To use a debugger
-  <%- if RUBY_VERSION < '2.0.0' -%>
-# gem 'debugger', group: [:development, :test]
-  <%- else -%>
 # gem 'byebug', group: [:development, :test]
-  <%- end -%>
 <% end -%>
 
 <% if RUBY_PLATFORM.match(/bccwin|cygwin|emx|mingw|mswin|wince|java/) -%>

railties/lib/rails/rack.rb

 module Rails
   module Rack
-    autoload :Debugger,      "rails/rack/debugger"   if RUBY_VERSION < '2.0.0'
-    autoload :Logger,        "rails/rack/logger"
+    autoload :Logger, "rails/rack/logger"
   end
 end

railties/lib/rails/rack/debugger.rb

-module Rails
-  module Rack
-    class Debugger
-      def initialize(app)
-        @app = app
+require 'active_support/deprecation'
 
-        ARGV.clear # clear ARGV so that rails server options aren't passed to IRB
-
-        require 'debugger'
-
-        ::Debugger.start
-        ::Debugger.settings[:autoeval] = true if ::Debugger.respond_to?(:settings)
-        puts "=> Debugger enabled"
-      rescue LoadError
-        puts "You're missing the 'debugger' gem. Add it to your Gemfile, bundle it and try again."
-        exit(1)
-      end
-
-      def call(env)
-        @app.call(env)
-      end
-    end
-  end
-end
+ActiveSupport::Deprecation.warn("This file is deprecated and will be removed in Rails 5.1 with no replacement.")

railties/test/commands/console_test.rb

@@ -46,28 +46,6 @@ def test_start_with_sandbox
     assert_match(/Loading \w+ environment in sandbox \(Rails/, output)
   end
 
-  if RUBY_VERSION < '2.0.0'
-    def test_debugger_option
-      console = Rails::Console.new(app, parse_arguments(["--debugger"]))
-      assert console.debugger?
-    end
-
-    def test_no_options_does_not_set_debugger_flag
-      console = Rails::Console.new(app, parse_arguments([]))
-      assert !console.debugger?
-    end
-
-    def test_start_with_debugger
-      stubbed_console = Class.new(Rails::Console) do
-        def require_debugger
-        end
-      end
-
-      rails_console = stubbed_console.new(app, parse_arguments(["--debugger"]))
-      silence_stream(STDOUT) { rails_console.start }
-    end
-  end
-
   def test_console_with_environment
     start ["-e production"]
     assert_match(/\sproduction\s/, output)

railties/test/generators/app_generator_test.rb

@@ -403,10 +403,7 @@ def test_inclusion_of_a_debugger
     if defined?(JRUBY_VERSION) || RUBY_ENGINE == "rbx"
       assert_file "Gemfile" do |content|
         assert_no_match(/byebug/, content)
-        assert_no_match(/debugger/, content)
       end
-    elsif RUBY_VERSION < '2.0.0'
-      assert_gem 'debugger'
     else
       assert_gem 'byebug'
     end

railties/test/generators/plugin_generator_test.rb

@@ -74,10 +74,7 @@ def test_inclusion_of_a_debugger
     if defined?(JRUBY_VERSION) || RUBY_ENGINE == "rbx"
       assert_file "Gemfile" do |content|
         assert_no_match(/byebug/, content)
-        assert_no_match(/debugger/, content)
       end
-    elsif RUBY_VERSION < '2.0.0'
-      assert_file "Gemfile", /# gem 'debugger'/
     else
       assert_file "Gemfile", /# gem 'byebug'/
     end