From: "rits (First Last)" <redmine@...>
Date: 2013-09-16T08:24:32+09:00
Subject: [ruby-core:57228] [ruby-trunk - Feature #7274] UnboundMethods	should be bindable to any object that is_a?(owner of the	UnboundMethod)


Issue #7274 has been updated by rits (First Last).


marcandre (Marc-Andre Lafortune) wrote:
> matz (Yukihiro Matsumoto) wrote:
> > The structure of instances of subclass (TT_XXX) may be different from superclasses.
> > In that case, the C implemented methods would crash.
> 
> I'm not sure I understand exactly what you are saying, but I am sure that the proposed patch would not cause crashes. Do you had a concrete example in mind?
> 
> Note that the request is not about binding methods across unrelated classes or going from a subclass up to a superclass (both of which could create crashes). It is only about using the actual owner instead of the class used to access it.
> 
> Can you explain why, for example, Kernel#dup can be bound to a String, but not if it was accessed using Array, even though the exact same code would be executed?
> 
>     Kernel.instance_method(:dup).bind("hello") # => accepted
>     Array.instance_method(:dup).bind("hello")  # => raises error, but really this is the same method.

It's also not clear to me what the concern is, please explain.

----------------------------------------
Feature #7274: UnboundMethods should be bindable  to any object that is_a?(owner of the UnboundMethod)
https://bugs.ruby-lang.org/issues/7274#change-41843

Author: rits (First Last)
Status: Rejected
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: next minor


as a corollary, UnboundMethods referencing the same method name on the same owner, should be equal

currently UnboundMethods binding is determined by the class via which they were retrieved, not the owner
____________________________________
class Base; def foo; end end
class Sub < Base; end

base_foo = Base.instance_method :foo
sub_foo = Sub.instance_method :foo
sub_foo.bind(Base.new).call
__________________________________

sub_foo.owner is Base so there does not seem to be any reason why it's not safe for it to bind to an instance of Base.

and there does not seem to be any reason for sub_foo and base_foo to be unequal, they both refer to the same method, foo on Base.


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