From: nobu@...
Date: 2014-03-05T06:56:57+00:00
Subject: [ruby-core:61302] [ruby-trunk - Bug #9593] [Closed] Keyword arguments default argument assignment behaviour not consistent with optional argument

Issue #9593 has been updated by Nobuyoshi Nakada.

Status changed from Open to Closed
% Done changed from 0 to 100

Applied in changeset r45272.

----------
parse.y: optional arguments in rhs

* parse.y (f_arg_asgn): define optional arguments as argument
  variables in the rhs default expressions.
  [ruby-core:61299] [Bug #9593]

----------------------------------------
Bug #9593: Keyword arguments default argument assignment behaviour not consistent with optional argument
https://bugs.ruby-lang.org/issues/9593#change-45633

* Author: Jack Chen
* Status: Closed
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* Category: syntax
* Target version: current: 2.2.0
* ruby -v: 2.1.1
* Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
Given the following code:

    def var
      100
    end

    def foo(var: var + 1)
      puts "var: #{var.inspect}"
    end

    def bar(var = var + 1)
      puts "var: #{var.inspect}"
    end

    foo(var: 1)
    foo rescue p $!

    bar(1)
    bar

Ruby 2.0.0:

    var: 1
    var: 101
    var: 1
    var: 101

Ruby 2.1.1:

    var: 1
    #<NoMethodError: undefined method `+' for nil:NilClass>
    var: 1
    var: 101

What appears to be happening is that since 2.1.1, the keyword argument defines `var` as a variable before evaluating the default argument. Personally, I prefer 2.0.0 behaviour, but the way 2.1.1 handles default arguments in non keyword arguments is inconsistent.



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