From: meanlogin@...
Date: 2014-09-25T01:44:40+00:00
Subject: [ruby-core:65266] [ruby-trunk - Bug #10293] splatting an empty hash in a method invocation sends an argument to the method (should send nothing)

Issue #10293 has been updated by First Last.


https://bugs.ruby-lang.org/issues/9291 is somewhat related
foo(**nil) should not raise since foo(*nil) does not and it's the more useful behavior

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Bug #10293: splatting an empty hash in a method invocation sends an argument to the method (should send nothing)
https://bugs.ruby-lang.org/issues/10293#change-49091

* Author: First Last
* Status: Assigned
* Priority: Normal
* Assignee: Nobuyoshi Nakada
* Category: core
* Target version: current: 2.2.0
* ruby -v: ruby 2.1.3p242 (2014-09-19 revision 47630) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: REQUIRED
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irb(main):001:0> def foo; end; foo **{}
ArgumentError: wrong number of arguments (1 for 0)

note that splatting an empty array results in no arguments

this behavior is particularly problematic with send (dispatching to different methods)

send method_name, *possibly_empty_arg_list, **possibly_empty_keyarg_hash

one should not have to do

if possibly_empty_keyarg_hash.empty?
  receiver.send method_name, *possibly_empty_arg_list
else  
  receiver.send method_name, *possibly_empty_arg_list, **possibly_empty_keyarg_hash
end

or

possibly_empty_arg_list << possibly_empty_keyarg_hash unless possibly_empty_keyarg_hash.empty?
receiver.send method_name, *possibly_empty_arg_list



-- 
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