From: Robert Klemme <shortcutter@...>
Date: 2010-01-22T22:53:45+09:00
Subject: [ruby-core:27697] Re: able to re-require $0

2010/1/22 Yusuke ENDOH <mame@tsg.ne.jp>:
> Hi,
>
> 2010/1/22 Benoit Daloze <eregontp@gmail.com>:
>> Hi,
>>> In similar, you can require the same library twice.
>>>
>>> �require "foo"
>>> �require "foo"
>>>
>> Excuse me, but at least in 1.9,
>> p require './test' #=> true
>> p require './test' #=> false
>> (the same happen with a stdlib, like benchmark of course)
>>
>> It's not loaded the second time. And it's very harmful to load 2 times
>> the same file, because it will redefine every method and constant...
>
> Yes. �I meant to say neither exception nor warning.
> OTOH, curcular require yields warning:
>
>
> foo.rb
> �require "./bar"
>
> bar.rb
> �require "./foo"
>
> $ ruby19 -W2 foo.rb
> /home/mame/work/ruby/foo.rb:1: warning: loading in progress, circular
> require considered harmful - /home/mame/work/ruby/bar.rb
> � � � �from foo.rb:1:in `<main>'
> � � � �from foo.rb:1:in `require'
> � � � �from /home/mame/work/ruby/bar.rb:1:in `<top (required)>'
> � � � �from /home/mame/work/ruby/bar.rb:1:in `require'
> � � � �from /home/mame/work/ruby/foo.rb:1:in `<top (required)>'
> � � � �from /home/mame/work/ruby/foo.rb:1:in `require'
>
>
> ... Ah, I get Roger's point now.
>
>
> bad.rb:
> �require $0
> �p :foo
>
> $ ruby19 ./bad.rb
> :foo
> :foo
>
>
> I don't know this is a bug or not, but I guess that Kurt is right.

I don't think it's worth fixing because a) it is unlikely that someone
requires $0 and b) even if that case would be prevented you can still
cause harm by having links in the filesystem pointing to the same
file.  Fixing that would require quite a bit of file system magic I
believe and that is probably not worthwhile because of the time and
runtime overhead (might have to do additional FS accesses).

My 0.02EUR

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
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