From: Adam Prescott <adam@...>
Date: 2011-08-05T19:06:47+09:00
Subject: [ruby-core:38814] Re: to_ary not respecting respond_to?

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On Thu, Aug 4, 2011 at 11:37 PM, Ryan Davis <ryand-ruby@zenspider.com>wrote:
>
> Extra Info:
> http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary/
>

Someone made a comment on that post linking to
http://yehudakatz.com/2010/01/02/the-craziest-fing-bug-ive-ever-seen/ which
explains, specifically for Array#flatten:

----

In Ruby 1.8, the process is essentially the following:

if obj.respond_to?(:to_ary)
  obj.__send__(:to_ary)
else
  obj
end

In Ruby 1.9, it was changed to:

begin
  obj.__send__(:to_ary)
rescue NoMethodError
  obj
end

----

I'm not sure why that changed happened, but at least that seems to be the
source of the behaviour.

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<div class=3D"gmail_quote">On Thu, Aug 4, 2011 at 11:37 PM, Ryan Davis <spa=
n dir=3D"ltr">&lt;<a href=3D"mailto:ryand-ruby@zenspider.com" target=3D"_bl=
ank">ryand-ruby@zenspider.com</a>&gt;</span> wrote:<blockquote class=3D"gma=
il_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-lef=
t:1ex">


Extra Info: <a href=3D"http://tenderlovemaking.com/2011/06/28/til-its-ok-to=
-return-nil-from-to_ary/" target=3D"_blank">http://tenderlovemaking.com/201=
1/06/28/til-its-ok-to-return-nil-from-to_ary/</a><br>
</blockquote></div><br><div>Someone made a comment on that post linking to=
=C2=A0<a href=3D"http://yehudakatz.com/2010/01/02/the-craziest-fing-bug-ive=
-ever-seen/" target=3D"_blank">http://yehudakatz.com/2010/01/02/the-crazies=
t-fing-bug-ive-ever-seen/</a>=C2=A0which explains, specifically for Array#f=
latten:</div>


<div><br></div><div>----</div><div><br></div>In Ruby 1.8, the process is es=
sentially the following:<br><br><div>if obj.respond_to?(:to_ary)<br>=C2=A0 =
obj.__send__(:to_ary)<br>else<br>=C2=A0 obj<br>end<br><br>In Ruby 1.9, it w=
as changed to:<br>

<br>begin<br>=C2=A0 obj.__send__(:to_ary)<br>
rescue NoMethodError<br>=C2=A0 obj<br><div><div>end</div></div><div><br></d=
iv><div>----</div><div><br></div><div>I&#39;m not sure why that changed hap=
pened, but at least that seems to be the source of the behaviour.</div>
</div>

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