[rubygems/rubygems] Restore and deprecate old deprecate method

https://github.com/rubygems/rubygems/commit/024267fa60

lib/rubygems/deprecate.rb

@@ -45,6 +45,31 @@ module Gem::Deprecate
     Gem::Version.new(Gem.rubygems_version.segments.first).bump
   end
 
+  ##
+  # Simple deprecation method that deprecates +name+ by wrapping it up
+  # in a dummy method. It warns on each call to the dummy method
+  # telling the user of +repl+ (unless +repl+ is :none) and the
+  # year/month that it is planned to go away.
+
+  def deprecate(name, repl, year, month)
+    class_eval do
+      old = "_deprecated_#{name}"
+      alias_method old, name
+      define_method name do |*args, &block|
+        klass = self.kind_of? Module
+        target = klass ? "#{self}." : "#{self.class}#"
+        msg = [ "NOTE: #{target}#{name} is deprecated",
+                repl == :none ? " with no replacement" : "; use #{repl} instead",
+                ". It will be removed on or after %4d-%02d-01." % [year, month],
+                "\n#{target}#{name} called from #{Gem.location_of_caller.join(":")}",
+        ]
+        warn "Gem::Deprecate#deprecate has been deprecated with no replacement and it will be removed in Rubygems 4.\n" unless Gem::Deprecate.skip
+        warn "#{msg.join}." unless Gem::Deprecate.skip
+        send old, *args, &block
+      end
+    end
+  end
+
   ##
   # Simple deprecation method that deprecates +name+ by wrapping it up
   # in a dummy method. It warns on each call to the dummy method

test/rubygems/test_deprecate.rb

@@ -54,6 +54,20 @@ class TestDeprecate < Gem::TestCase
 
   end
 
+  class OtherThing
+
+    extend Gem::Deprecate
+    attr_accessor :message
+    def foo
+      @message = "foo"
+    end
+    def bar
+      @message = "bar"
+    end
+    deprecate :foo, :bar, 2099, 3
+
+  end
+
   def test_deprecated_method_calls_the_old_method
     capture_io do
       thing = Thing.new
@@ -91,4 +105,16 @@ class TestDeprecate < Gem::TestCase
     Gem::Commands.send(:remove_const, :FooCommand)
   end
 
+  def test_deprecated_method_outputs_a_warning_old_way
+    out, err = capture_io do
+      thing = OtherThing.new
+      thing.foo
+    end
+
+    assert_equal "", out
+    assert_match(/Gem::Deprecate#deprecate has been deprecated with no replacement and it will be removed in Rubygems 4\./, err)
+    assert_match(/Thing#foo is deprecated; use bar instead\./, err)
+    assert_match(/on or after 2099-03-01/, err)
+  end
+
 end