From: Heesob Park <redmine@...>
Date: 2009-07-31T14:16:53+09:00
Subject: [ruby-core:24638] [Bug #1846] Unexpected behavior of hash of array

Bug #1846: Unexpected behavior of hash of array
http://redmine.ruby-lang.org/issues/show/1846

Author: Heesob Park
Status: Open, Priority: Low
Category: core, Target version: 1.9.1
ruby -v: ruby 1.9.1p243 (2009-07-16 revision 24175) [i686-linux]

I noticed some unexpected behaviors of hash with array key

irb(main):001:0> h={}
=> {}
irb(main):002:0> a=[]
=> []
irb(main):003:0> h[a]=1
=> 1
irb(main):004:0> a<<1
=> [1]
irb(main):005:0> h[a]=2
=> 2
irb(main):006:0> a<<2
=> [1, 2]
irb(main):007:0> h[a]=3
=> 3
irb(main):008:0> h
=> {[1, 2]=>1, [1, 2]=>2, [1, 2]=>3}
irb(main):009:0> h[a]
=> 3
irb(main):010:0> h[[1,2]]
=> 3
irb(main):011:0> Marshal.load(Marshal.dump(h))
=> {[1, 2]=>3}
irb(main):012:0> h.delete(a)
=> 3
irb(main):013:0> h
=> {[1, 2]=>1, [1, 2]=>2}
irb(main):014:0> h[a]
=> nil
irb(main):015:0> h.delete(a)
=> 1
irb(main):016:0> h
=> {[1, 2]=>2}
irb(main):017:0> h[a]
=> nil
irb(main):018:0> h.delete(a)
=> nil


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