From: "marcandre (Marc-Andre Lafortune)" <ruby-core@...>
Date: 2013-02-15T00:57:48+09:00
Subject: [ruby-core:52260] [ruby-trunk - Bug #7836][Open] Need a way to get Method and UnboundMethod objects to methods overridden by prepended modules


Issue #7836 has been updated by marcandre (Marc-Andre Lafortune).

Status changed from Closed to Open
Assignee set to matz (Yukihiro Matsumoto)

Matz, could you please confirm?

I'm not sure what is the right approach. What should A.instance_method(:hello) return:

1) the method that `A.new.hello` will execute, or
2) the method defined in A?

I feel that 1) is currently the case. Otherwise, strictly speaking, `String.instance_method(:object_id)` would raise a NameError!

I would expect:

  meth = A.instance_method :hello
  a = A.new
  meth.bind(a).call `# should be the same effect as a.bar
  meth.source_location ` # thus should be the same as a.method(:hello).source_location
  meth.owner ` # and thus should be the same as a.method(:hello).owner

This is currently true in Ruby 1.9, and this patch changes that.

I agree with John Mair that there should be a way to get the proper instance method of a class, as he suggests. I would add that String.instance_method(:object_id, false) should raise a NameError, as there is no such instance method defined in String.
----------------------------------------
Bug #7836: Need a way to get Method and UnboundMethod objects to methods overridden by prepended modules
https://bugs.ruby-lang.org/issues/7836#change-36291

Author: banister (john mair)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: 
Target version: 
ruby -v: 2.0.0dev


=begin
See the following code:

  module P
    def hello
      puts "from P"
      super
    end
  end

  class A
    def hello
      puts 'from A'
    end

    prepend P
  end

  A.instance_method(:hello).source_location == P.instance_method(:hello).source_location  #=> true

== Discussion

Since (({A.instance_method(:hello)})) effectively returns (({P.instance_method(:hello)})) it is impossible to get an (({UnboundMethod})) object to the original (({A#hello})) method.

Tools like ((<[Pry]|URL:http://pryrepl.org>)) need to access (({UnboundMethod})) objects to every active method in the system for debugging purposes.

== Possible solution

Simply allow (({instance_method()})) to take a second boolean parameter, indicating whether methods injected by prepended modules are to be included, it would default to true:

example:

  A.instance_method(:hello) #=> same as P#hello
  A.instance_method(:hello, false) #=> return strictly A#hello

=end



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