Issue #9913 has been updated by Tomoyuki Chikanaga.

Backport changed from 2.0.0: REQUIRED, 2.1: REQUIRED to 2.0.0: REQUIRED, 2.1: DONE

Backported into `ruby_2_1` branch at r46809.

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Bug #9913: Digest == throws TypeError when testing against nil
https://bugs.ruby-lang.org/issues/9913#change-47744

* Author: Bryan Hockey
* Status: Closed
* Priority: Normal
* Assignee: 
* Category: lib
* Target version: 
* ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]
* Backport: 2.0.0: REQUIRED, 2.1: DONE
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Also present in ruby -v: jruby 1.7.10 (1.9.3p392) 2014-01-09 c4ecd6b on OpenJDK 64-Bit Server VM 1.7.0_55-b14 [linux-amd64]

To recreate: 

require 'digest'
x = Digest::SHA256.new()
x == nil
TypeError: can't convert nil into String

Workaround:
w1: use #nil?
w2: reverse rhs, lhs, e.g. if nil == some_digest



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