module Gem::Deprecate

def self.next_rubygems_major_version # :nodoc:
  Gem::Version.new(Gem.rubygems_version.segments.first).bump
end

def self.skip # :nodoc:
  @skip ||= false
end

def self.skip=(v) # :nodoc:
  @skip = v
end

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 "#{msg.join}." unless Gem::Deprecate.skip
      send old, *args, &block
    end
  end
end

def rubygems_deprecate(name, replacement=:none)
  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",
              replacement == :none ? " with no replacement" : "; use #{replacement} instead",
              ". It will be removed in Rubygems #{Gem::Deprecate.next_rubygems_major_version}",
              "\n#{target}#{name} called from #{Gem.location_of_caller.join(":")}",
      ]
      warn "#{msg.join}." unless Gem::Deprecate.skip
      send old, *args, &block
    end
  end
end

def rubygems_deprecate_command
  class_eval do
    define_method "deprecated?" do
      true
    end
    define_method "deprecation_warning" do
      msg = [ "#{self.command} command is deprecated",
              ". It will be removed in Rubygems #{Gem::Deprecate.next_rubygems_major_version}.\n",
      ]
      alert_warning "#{msg.join}" unless Gem::Deprecate.skip
    end
  end
end

def skip_during
  Gem::Deprecate.skip, original = true, Gem::Deprecate.skip
  yield
ensure
  Gem::Deprecate.skip = original
end