From: "nobu (Nobuyoshi Nakada)" <nobu@...>
Date: 2012-06-13T05:13:19+09:00
Subject: [ruby-core:45601] [ruby-trunk - Bug #6580][Rejected] Assigning a value to a single element in an array that is contained in an array of arrays, updates the element in that position in all of the contained	arrays


Issue #6580 has been updated by nobu (Nobuyoshi Nakada).

Status changed from Open to Rejected


----------------------------------------
Bug #6580: Assigning a value to a single element in an array that is contained in an array of arrays, updates the element in that position in all of the contained arrays
https://bugs.ruby-lang.org/issues/6580#change-27199

Author: jmoline (James Moline)
Status: Rejected
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin10.8.0]


=begin
Came across this bug the other day in both 1.8 and 1.9.3. It seems like it would have been discovered before, but I can't find anywhere that it has been reported.

Basically, when you have an array of arrays, and you attempt to assign a value to a single element of one of those arrays, it assigns the value to that element in all of the arrays.

Example:

(({arr = Array.new(5, Array.new(5))}))

  [
    [nil, nil, nil, nil, nil],
    [nil, nil, nil, nil, nil],
    [nil, nil, nil, nil, nil],
    [nil, nil, nil, nil, nil],
    [nil, nil, nil, nil, nil]
  ]

(({arr[0][0] = 3}))

  [
    [3, nil, nil, nil, nil],
    [3, nil, nil, nil, nil],
    [3, nil, nil, nil, nil],
    [3, nil, nil, nil, nil],
    [3, nil, nil, nil, nil],
  ]

(({arr[2][3] = "test"}))

  [
    [3, nil, nil, "test", nil],
    [3, nil, nil, "test", nil],
    [3, nil, nil, "test", nil],
    [3, nil, nil, "test", nil],
    [3, nil, nil, "test", nil],
  ]
=end


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