From: "ddebernardy (Denis de Bernardy)" <ddebernardy@...>
Date: 2012-11-09T02:32:10+09:00
Subject: [ruby-core:49118] [ruby-trunk - Bug #6037] #freeze bug


Issue #6037 has been updated by ddebernardy (Denis de Bernardy).


Adding a note in case someone new to ruby ever wonders why it got rejected.

    >> array = ['a', 'b'].freeze
    => ["a", "b"]
    >> puts array.map { |o| o.object_id }
    70282007609720
    70282007609700
    => nil
    >> array[0].gsub!(/.+/s, 'b')
    => "b"
    >> puts array.map { |o| o.object_id }
    70282007609720
    70282007609700
    >> array.map { |o| o.gsub!(/.+/s, 'c') }
    => ["c", "c"]
    >> puts array.map { |o| o.object_id }
    70282007609720
    70282007609700
    => nil

In other words, `gsub!` for an array is equivalent to calling `map { |o| o.gsub! ... }`.
----------------------------------------
Bug #6037: #freeze bug
https://bugs.ruby-lang.org/issues/6037#change-32650

Author: ddebernardy (Denis de Bernardy)
Status: Rejected
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: 1.9.3


freeze should deep freeze, to avoid inconsistent behavior:

array = ['a', 'b'].freeze
array[0] = 'b'
array[0].gsub!(/.+/s, 'b')
array

>> RUBY_VERSION
=> "1.9.3"
>> array = ['a', 'b'].freeze
=> ["a", "b"]
>> array[0] = 'b'
RuntimeError: can't modify frozen Array
	from (irb):269:in `[]='
	from (irb):269
	from /opt/local/bin/irb:12:in `<main>'
>> array[0].gsub!(/.+/s, 'b')
=> "b"
>> array
=> ["b", "b"]



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