[ruby-core:27697] Re: able to re-require $0

2010/1/22 Yusuke ENDOH <[e-mail]>:
> Hi,
>
> 2010/1/22 Benoit Daloze <[e-mail]>:
>> Hi,
>>> In similar, you can require the same library twice.
>>>
>>> equire "foo"
>>> equire "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.  meant to say neither exception nor warning.
> OTOH, curcular require yields warning:
>
>
> foo.rb
> equire "./bar"
>
> bar.rb
> equire "./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
> rom foo.rb:1:in `<main>'
> rom foo.rb:1:in `require'
> rom /home/mame/work/ruby/bar.rb:1:in `<top (required)>'
> rom /home/mame/work/ruby/bar.rb:1:in `require'
> rom /home/mame/work/ruby/foo.rb:1:in `<top (required)>'
> rom /home/mame/work/ruby/foo.rb:1:in `require'
>
>
> ... Ah, I get Roger's point now.
>
>
> bad.rb:
> equire $0
>  :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

-- 
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