Bug #11236: inconsistent behavior using ** vs hash as method parameter

• Status: Open
• Priority: Normal
• Assignee: -
• Target version: -
• ruby -v: ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-linux]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN

[akostadinov (Aleksandar Kostadinov)]

Using ruby 2.2.2 I see this work:

[18] pry(main)> def test(cmd, opts={})
[18] pry(main)*   puts cmd,opts
[18] pry(main)* end  
=> :test
[19] pry(main)> test(:ads, :d => 6, :f => :gah, {a:3,b:4} => 3)
ads
{:d=>6, :f=>:gah, {:a=>3, :b=>4}=>3}
=> nil

But this fails:

[2] pry(main)> def test(cmd, **opts)
[2] pry(main)*   puts cmd, opts
[2] pry(main)* end  
[9] pry(main)> test(:ads, :d => 6, :f => :gah, {a:3,b:4} => 3)
ArgumentError: wrong number of arguments (2 for 1)
from (pry):2:in `test'

[jeremyevans0 (Jeremy Evans)]

This is expected behavior, keyword argument hashes only support symbol keys, not hash keys. I suppose the error message could be better, though.

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

What message would be better?

[akostadinov (Aleksandar Kostadinov)]

Nobuyoshi Nakada wrote:

What message would be better?

Unsupported key type?

btw what is the reason to have that limitation? Not that I need this functionality, I just happened to notice the difference...

[hsbt (Hiroshi SHIBATA)]

• Related to Feature #14183: "Real" keyword argument added

[marcandre (Marc-Andre Lafortune)]

When last argument is hash-like but has keys that are not symbols, we could output instead "wrong number of arguments (2 for 1); note that the last argument has keys that are not symbols and thus was not considered as keyword parameters"