From: Motohiro KOSAKI <kosaki.motohiro@...>
Date: 2011-08-20T19:08:49+09:00
Subject: [ruby-core:39033] [Ruby 1.9 - Bug #5124] foo = [*bar] implies foo.equal?(bar)


Issue #5124 has been updated by Motohiro KOSAKI.


Sasada-san, ping?
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Bug #5124: foo = [*bar] implies foo.equal?(bar)
http://redmine.ruby-lang.org/issues/5124

Author: Michael Edgar
Status: Assigned
Priority: Normal
Assignee: Koichi Sasada
Category: core
Target version: 1.9.3
ruby -v: ruby 1.9.2p188 (2011-03-28 revision 31204) [x86_64-darwin10.7.0]


I just ran into this as a result of some slightly sloppy coding, but it did disagree with my internal assumptions.

Normally, I expect the Array literal syntax to create a new object, every time. So when I rewrote some code and ended up with something similar to the following, my tests broke, and I'm not sure that's how it should be. Here's the reduced test case:

some_ary = [1, 2, 3]
bar = [*some_ary]
bar << 4

p bar
>> [1, 2, 3, 4]
p some_ary
>> [1, 2, 3, 4]

I see it's clearly taking an opportunity for optimization, so I'm more than happy to hear that as a reason for rejecting this. It does warrant documentation somewhere, though, I'd say. Not sure where that documentation would go.


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