## mark a section (Learn more)

require "thread" Thread.abort_on_exception = true module Kernel alias unsafe_require require @@__require_mutex = Mutex.new def require(*args) @@__require_mutex.synchronize do unsafe_require(*args) end end end t1 = Thread.new do require "foo" Foo.new end t2 = Thread.new do require "foo" Foo.new end t1.join; t2.join

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