Sync latest development version of bundler & rubygems

Merged: https://github.com/ruby/ruby/pull/4143

lib/rubygems/core_ext/tcpsocket_init.rb

@@ -0,0 +1,52 @@
+require 'socket'
+
+module CoreExtensions
+  module TCPSocketExt
+    def self.prepended(base)
+      base.prepend Initializer
+    end
+
+    module Initializer
+      CONNECTION_TIMEOUT = 5
+      IPV4_DELAY_SECONDS = 0.1
+
+      def initialize(host, serv, *rest)
+        mutex = Mutex.new
+        addrs = []
+        threads = []
+        cond_var = ConditionVariable.new
+
+        Addrinfo.foreach(host, serv, nil, :STREAM) do |addr|
+          Thread.report_on_exception = false if defined? Thread.report_on_exception = ()
+
+          threads << Thread.new(addr) do
+            # give head start to ipv6 addresses
+            sleep IPV4_DELAY_SECONDS if addr.ipv4?
+
+            # raises Errno::ECONNREFUSED when ip:port is unreachable
+            Socket.tcp(addr.ip_address, serv, connect_timeout: CONNECTION_TIMEOUT).close
+            mutex.synchronize do
+              addrs << addr.ip_address
+              cond_var.signal
+            end
+          end
+        end
+
+        mutex.synchronize do
+          timeout_time = CONNECTION_TIMEOUT + Time.now.to_f
+          while addrs.empty? && (remaining_time = timeout_time - Time.now.to_f) > 0
+            cond_var.wait(mutex, remaining_time)
+          end
+
+          host = addrs.shift unless addrs.empty?
+        end
+
+        threads.each {|t| t.kill.join if t.alive? }
+
+        super(host, serv, *rest)
+      end
+    end
+  end
+end
+
+TCPSocket.prepend CoreExtensions::TCPSocketExt