Issue #9906 has been reported by Martin Sarsale.

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Bug #9906: duplicated require of '.so' files?
https://bugs.ruby-lang.org/issues/9906

* Author: Martin Sarsale
* Status: Open
* Priority: Normal
* Assignee: 
* Category: core
* Target version: 
* ruby -v: ruby 2.1.0p0 (2013-12-25 revision 44422) [i686-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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Dear all,

We are trying to get rid of autoload;
We could require everything in the first line of the file but instead we
prefer to require only what we need, when we need it.

So, instead of

 require "digest/md5"
 def foo(n)
  Digest::MD5.hexdigest(n)
 end

we would like to do:

 def foo(n)
  require "digest/md5"
  Digest::MD5.hexdigest(n)
 end


The problem we've found, is that duplicate `require(name)`, satisfied by
".rb" files are only executed once; but when file loaded by
require(name) is a '.so', next requires with the same name will be
executed again and again.

Example:

$ cat require-rb.rb

def foo(n)
  require "set"
  Set.new([n])
end
1000.times{|n|
  puts foo(n)
}

$ strace -e trace=file -o require-rb.log ruby require-rb.rb
$ grep -c -E 'open.*/set'  require-rb.log
8


$ cat require-so.rb

def foo(n)
  require "digest/md5"
  Digest::MD5.hexdigest(n.to_s)
end
1000.times{|n|
  puts foo(n)
}

$ strace -e trace=file -o require-so.log ruby require-so.rb
$ grep -c -E 'open.*/md5'  require-so.log
16001


Is this a bug or a feature?



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