From: Florian Gross <florgro@...>
Date: 2007-06-29T11:10:25+09:00
Subject: [BUG] delete_if with destructive methods in block

Hi,

Here's some odd Hash#delete_if behaviour:

h = {1 => 2, 3 => 4, 5 => 6}
h.delete_if do |*a|
  p a
  h.shift

  p h
  puts

  true
end

It outputs the following:

[5, 6]
{1=>2, 3=>4}

[5]
{3=>4}

[3, 4]
{}

[3]
{}

The same behaviour can be produced by replacing h.shift with
h.delete(h.keys.first).

It happens for me on ruby 1.9.0 (2007-04-02 patchlevel 0) and ruby
1.8.4 (2005-12-24).

I'm not sure why this happens instead of a hash modified during
iteration exception being raised.

Kind regards,
Florian Gross