JRuby的Kernel #__ method__的实现是否被破坏? [英] Is JRuby's implementation of Kernel#__method__ broken?

问题描述

这是Kernel#__method__的描述根据Ruby-Doc.org (强调):

在当前方法的定义处返回名称 作为符号.如果在方法外部调用，它将返回nil.

Returns the name at the definition of the current method as a Symbol. If called outside of a method, it returns nil.

现在考虑以下代码片段:

Now consider the following code snippet:

DEFINITION = proc { __method__ }

class C
  define_method :one, DEFINITION
  define_method :two, DEFINITION
end

o = C.new

当我使用MRI v1.8.7 +运行以下命令时，我得到了预期的结果:

When I run the following using MRI v1.8.7+ I'm getting the expected results:

o.one  #=> :one
o.two  #=> :two

但是，当我使用JRuby 1.7+运行相同的代码时(我尚未测试以前的版本):

However when I run the same code using JRuby 1.7+ (I haven't tested the previous versions):

o.one  #=> :two
o.two  #=> :two

这是否可以视为JRuby实现中的缺陷，或者仅仅是对Kernel#__method__的另一种解释?

Could this be considered a defect in JRuby's implementation or is it simply a different interpretation of Kernel#__method__?

推荐答案

这可能是JRuby实现的__method__的缺陷，或者可能是实现的define_method的错误，或者可能受到严格限制两者一起使用.看看使用&运算符将Proc对象转换为块时会发生什么:

It may be a defect in JRuby's implementation of __method__, or it may be a bug in the implementation of define_method, or it may be strictly limited to the use of the two together. Look what happens if you cast the Proc object into a block by using the & operator:

DEFINITION = proc { __method__ }

class C
  define_method :one, &DEFINITION
  define_method :two, &DEFINITION
end

o = C.new

现在像以前一样在MRI中:

Now in MRI, as before:

o.one  #=> :one
o.two  #=> :two

但是，在JRuby中，它是固定的:

However, in JRuby, it's fixed:

o.one  #=> :one
o.two  #=> :two

考虑到MRI的define_method的内部实现，其中包括Proc自变量与块自变量的处理，如果JRuby的相似之处，也可能是问题所在.

Given the internal implementation of MRI's define_method, which includes the handling of Proc arguments vs block arguments, if JRuby's is at all similar, it's also possible that that is where the problem could lie.

无论哪种方式，都无法通过将__method__替换为self，binding，object_id或它们的任何组合或排列来找到相似之处，因此，该问题肯定是局限在.

Either way, there are no parallels to be found by replacing __method__ with self, binding, object_id, or any combination or permutation of them, so the issue is certainly localized to uses of __method__.

更新:扭曲结尾

这是MRI中的一个已知错误1.9.2 ，并且JRuby的实现反映了该行为.

This was a known bug in MRI 1.9.2, and JRuby's implementation mirrors that behavior.

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