From: "drbrain (Eric Hodel)" <drbrain@...7.net>
Date: 2013-07-04T08:06:13+09:00
Subject: [ruby-core:55789] [ruby-trunk - Bug #8374] race condition when two threads require a gem


Issue #8374 has been updated by drbrain (Eric Hodel).

Subject changed from race condition when two threads require a gem with a C extension to race condition when two threads require a gem

This is reproducible without a C extension, updated subject.
----------------------------------------
Bug #8374: race condition when two threads require a gem
https://bugs.ruby-lang.org/issues/8374#change-40283

Author: vjoel (Joel VanderWerf)
Status: Assigned
Priority: Normal
Assignee: drbrain (Eric Hodel)
Category: lib
Target version: 
ruby -v: ruby 2.0.0p0 (2013-02-24) [i686-linux]
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


=begin
Requiring a gem with a C extension seems to be not threadsafe.

Any one of the require lines below will frequently (but not always) cause an error like the following:

  /usr/local/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require': cannot load such file -- sqlite3 (LoadError)
        from /usr/local/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require'
        from thread.rb:7:in `block (2 levels) in <main>'

Using one thread avoids the problem.

  ths = (1..2).map do
    Thread.new do
  #    require 'msgpack'
  #    require 'yajl'
  #    require 'sequel'
  #    require 'nio4r'
      require 'sqlite3'
    end
  end

  ths.each {|th| th.join}
=end



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