Forum: Ruby-core [ruby-trunk - Bug #7663][Open] Unable to invoke a method with `**kwargs` if the receiver doesn't def

Issue #7663 has been reported by wycats (Yehuda Katz).

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Bug #7663: Unable to invoke a method with `**kwargs` if the receiver 
doesn't define keyword arguments
https://bugs.ruby-lang.org/issues/7663

Author: wycats (Yehuda Katz)
Status: Open
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: 2.0.0dev


This works:

  def hello
    puts "hello"
  end

  hello(*[])

This does not:

  def hello
    puts "hello"
  end

  hello(**{})

I may be misunderstanding the idea behind the keyword arguments, but I 
would expect them to behave similarly to regular arguments when used 
with splat.

Issue #7663 has been updated by matz (Yukihiro Matsumoto).

Status changed from Open to Rejected

Unlike regular argument, empty keyword argument is not equal to empty 
regular list.

Matz.

----------------------------------------
Bug #7663: Unable to invoke a method with `**kwargs` if the receiver 
doesn't define keyword arguments
https://bugs.ruby-lang.org/issues/7663#change-35239

Author: wycats (Yehuda Katz)
Status: Rejected
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: 2.0.0dev


This works:

  def hello
    puts "hello"
  end

  hello(*[])

This does not:

  def hello
    puts "hello"
  end

  hello(**{})

I may be misunderstanding the idea behind the keyword arguments, but I 
would expect them to behave similarly to regular arguments when used 
with splat.

Issue #7663 has been updated by mame (Yusuke Endoh).


In the current design, keyword arguments are NOT omittable at a callee 
side.
In other words, you cannot pass keyword arguments to a method that does 
not support keyword argments.

Other possible behavior is to ignore the passed arguments silently (as 
you expected), but I'm afraid if it is rather error-prone than useful. 
It tends to hide bugs.

If you really want to do so, you can use `**` parameter explicitly.

  def hello(**dummy)
    puts "hello"
  end

A bare `**` (#7662) is indeed useful in this use case.  I'm not so 
positive to this use case itself, though.
----------------------------------------
Bug #7663: Unable to invoke a method with `**kwargs` if the receiver 
doesn't define keyword arguments
https://bugs.ruby-lang.org/issues/7663#change-35251

Author: wycats (Yehuda Katz)
Status: Rejected
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: 2.0.0dev


This works:

  def hello
    puts "hello"
  end

  hello(*[])

This does not:

  def hello
    puts "hello"
  end

  hello(**{})

I may be misunderstanding the idea behind the keyword arguments, but I 
would expect them to behave similarly to regular arguments when used 
with splat.