new --reduce-compat option removes Module#const_missing and Deprecate…

…dObjectDSL

bin/rake

@@ -28,6 +28,10 @@ begin
 rescue LoadError
 end
 
+module Rake
+  REDUCE_COMPAT = true if ARGV.include?("--reduce-compat")
+end
+
 require 'rake'
 
 Rake.application.run

lib/rake/application.rb

@@ -349,6 +349,11 @@ def standard_rake_options
           # HACK Use File::PATH_SEPARATOR
           lambda { |value| options.rakelib = value.split(':') }
         ],
+        ['--reduce-compat', "Remove DSL in Object; remove Module#const_missing which defines ::Task etc.",
+          # Load-time option.
+          # Handled in bin/rake where Rake::REDUCE_COMPAT is defined (or not).
+          lambda { |_| }
+        ],
         ['--require', '-r MODULE', "Require MODULE before executing rakefile.",
           lambda { |value|
             begin

lib/rake/dsl_definition.rb

@@ -165,10 +165,10 @@ def #{name}(*args, &block)
         private :#{name}
       }, __FILE__, line
     end
-  end
+  end unless defined? Rake::REDUCE_COMPAT
 
   extend FileUtilsExt
 end
 
 self.extend Rake::DSL
-include Rake::DeprecatedObjectDSL
+include Rake::DeprecatedObjectDSL unless defined? Rake::REDUCE_COMPAT

lib/rake/ext/module.rb

@@ -36,4 +36,4 @@ def const_missing(const_name)
       rake_original_const_missing(const_name)
     end
   end
-end
+end unless defined? Rake::REDUCE_COMPAT

test/test_rake_reduce_compat.rb

@@ -0,0 +1,65 @@
+require File.expand_path('../helper', __FILE__)
+require 'open3'
+
+class TestRakeReduceCompat < Rake::TestCase
+  # TODO: factor out similar code in test_rake_functional.rb
+  def rake(*args)
+    lib = File.join(@orig_PWD, "lib")
+    bin_rake = File.join(@orig_PWD, "bin", "rake")
+    Open3.popen3(RUBY, "-I", lib, bin_rake, *args) { |_, out, _, _| out.read }
+  end
+
+  def invoke_normal(task_name)
+    rake task_name.to_s
+  end
+
+  def invoke_reduce_compat(task_name)
+    rake "--reduce-compat", task_name.to_s
+  end
+
+  def test_no_deprecated_dsl
+    rakefile %q{
+      task :check_task do
+        Module.new { p defined?(task) }
+      end
+
+      task :check_file do
+        Module.new { p defined?(file) }
+      end
+    }
+
+    assert_equal %{"method"}, invoke_normal(:check_task).chomp
+    assert_equal %{"method"}, invoke_normal(:check_file).chomp
+
+    assert_equal "nil", invoke_reduce_compat(:check_task).chomp
+    assert_equal "nil", invoke_reduce_compat(:check_file).chomp
+  end
+
+  def test_no_classic_namespace
+    rakefile %q{
+      task :check_task do
+        begin
+          Task
+          print "present"
+        rescue NameError
+          print "absent"
+        end
+      end
+
+      task :check_file_task do
+        begin
+          FileTask
+          print "present"
+        rescue NameError
+          print "absent"
+        end
+      end
+    }
+
+    assert_equal "present", invoke_normal(:check_task)
+    assert_equal "present", invoke_normal(:check_file_task)
+
+    assert_equal "absent", invoke_reduce_compat(:check_task)
+    assert_equal "absent", invoke_reduce_compat(:check_file_task)
+  end
+end