From: Shyouhei Urabe <shyouhei@...>
Date: 2012-02-13T16:59:46+09:00
Subject: [ruby-core:42525] [ruby-trunk - Bug #6008][Feedback] {a: 1}.hash not consistent over VM restarts


Issue #6008 has been updated by Shyouhei Urabe.

Status changed from Open to Feedback

Jens Berlips wrote:
> Which implies that you should get the behaviour in 1.8.7.

Why?  I can't get it.  I was wondering if you could describe it in detail.
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Bug #6008: {a: 1}.hash not consistent over VM restarts
https://bugs.ruby-lang.org/issues/6008

Author: Jens Berlips
Status: Feedback
Priority: Normal
Assignee: 
Category: core
Target version: 1.9.3
ruby -v: ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin11.0.0]


$ ruby -e 'puts ({a: 1}.hash)'
-2419336229553239378
$ ruby -e 'puts ({a: 1}.hash)'
-4506930541181251952
$ ruby -e 'puts ({a: 1}.hash)'
2108665473238231010
$ ruby -e 'puts ({a: 1}.hash)'
-3675793335936991568

But if you go to rvm 1.8.7

ruby -e 'puts ({:a => 1}.hash)'
425023
ruby -e 'puts ({:a => 1}.hash)'
425023
ruby -e 'puts ({:a => 1}.hash)'
425023

The documentation read:

> Generates a Fixnum hash value for this object. This function must have the property that a.eql?(b) implies a.hash == b.hash. The hash value is used by class Hash. Any hash value that exceeds the capacity of a Fixnum will be truncated before > being used.

Which implies that you should get the behaviour in 1.8.7.

Regards, 
Jens



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