3 files changed, 3 insertions, 35 deletions
diff --git a/activesupport/lib/active_support/core_ext/kernel.rb b/activesupport/lib/active_support/core_ext/kernel.rb
index 293a3b2619..364ed9d65f 100644
--- a/activesupport/lib/active_support/core_ext/kernel.rb
+++ b/activesupport/lib/active_support/core_ext/kernel.rb
@@ -1,5 +1,4 @@
 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'
diff --git a/activesupport/lib/active_support/core_ext/kernel/debugger.rb b/activesupport/lib/active_support/core_ext/kernel/debugger.rb
index ddf66b2022..1fde3db070 100644
--- a/activesupport/lib/active_support/core_ext/kernel/debugger.rb
+++ b/activesupport/lib/active_support/core_ext/kernel/debugger.rb
@@ -1,10 +1,3 @@
-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.")
diff --git a/activesupport/test/core_ext/kernel_test.rb b/activesupport/test/core_ext/kernel_test.rb
index 8abbd6c69b..503e6595cb 100644
--- a/activesupport/test/core_ext/kernel_test.rb
+++ b/activesupport/test/core_ext/kernel_test.rb
@@ -65,27 +65,3 @@ class MockStdErr
     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'