rubyinheritancemetaprogrammingalias-method

Unexpected value of __callee__ when including a module – is this a Ruby bug?

When invoked via a method created by alias_method, __callee__ ignores the name of the old method (here xxx) and returns the name of the new method, as below:

class Foo
  def xxx() __callee__ end
  alias_method :foo, :xxx
end

Foo.new.foo # => :foo

This behavior holds even when xxx is inherited from a superclass:

class Sup
  def xxx() __callee__ end
end

class Bar < Sup
  alias_method :bar, :xxx
end

Bar.new.bar # => :bar

Given both of the above, I would expect that the same behavior would hold when xxx is included via a module. However, that is not the case:

module Mod
  def xxx() __callee__ end
end

class Baz
  include Mod
  alias_method :baz, :xxx
end

Baz.new.baz # => :xxx

I expect the return value to be :baz, not :xxx.

The above code was executed using Ruby 2.3.1p112. Is this a bug in the implementation of __callee__? Or maybe of alias_method? And if not, can anyone explain why module inclusion behaves differently?

UPDATE 1

I've posted this to the Ruby bug tracker to try to stir up an answer.

UPDATE 2

Apparently, I'm not the only one to be surprised by this issue. I wonder whether Revision 50728 (which was meant to solve Bug 11046: __callee__ returns incorrect method name in orphan proc) might be related.

Solution

  • This was a bug, and it was closed 3 days ago with this note:

    Seems fixed by r56592.