Bug #7663: Unable to invoke a method with `**kwargs` if the receiver doesn't define keyword arguments

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: 2.0.0dev

[wycats (Yehuda Katz)]

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.

[matz (Yukihiro Matsumoto)]

• Status changed from Open to Rejected

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

Matz.

[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.