Added bundler as default gems. Revisit [Feature #12733]

* bin/*, lib/bundler/*, lib/bundler.rb, spec/bundler, man/*:
    Merge from latest stable branch of bundler/bundler repository and
    added workaround patches. I will backport them into upstream.
  * common.mk, defs/gmake.mk: Added `test-bundler` task for test suite
    of bundler.
  * tool/sync_default_gems.rb: Added sync task for bundler.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65509 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/bundler/cli/exec.rb

@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+require "bundler/current_ruby"
+
+module Bundler
+  class CLI::Exec
+    attr_reader :options, :args, :cmd
+
+    TRAPPED_SIGNALS = %w[INT].freeze
+
+    def initialize(options, args)
+      @options = options
+      @cmd = args.shift
+      @args = args
+
+      if Bundler.current_ruby.ruby_2? && !Bundler.current_ruby.jruby?
+        @args << { :close_others => !options.keep_file_descriptors? }
+      elsif options.keep_file_descriptors?
+        Bundler.ui.warn "Ruby version #{RUBY_VERSION} defaults to keeping non-standard file descriptors on Kernel#exec."
+      end
+    end
+
+    def run
+      validate_cmd!
+      SharedHelpers.set_bundle_environment
+      if bin_path = Bundler.which(cmd)
+        if !Bundler.settings[:disable_exec_load] && ruby_shebang?(bin_path)
+          return kernel_load(bin_path, *args)
+        end
+        # First, try to exec directly to something in PATH
+        if Bundler.current_ruby.jruby_18?
+          kernel_exec(bin_path, *args)
+        else
+          kernel_exec([bin_path, cmd], *args)
+        end
+      else
+        # exec using the given command
+        kernel_exec(cmd, *args)
+      end
+    end
+
+  private
+
+    def validate_cmd!
+      return unless cmd.nil?
+      Bundler.ui.error "bundler: exec needs a command to run"
+      exit 128
+    end
+
+    def kernel_exec(*args)
+      ui = Bundler.ui
+      Bundler.ui = nil
+      Kernel.exec(*args)
+    rescue Errno::EACCES, Errno::ENOEXEC
+      Bundler.ui = ui
+      Bundler.ui.error "bundler: not executable: #{cmd}"
+      exit 126
+    rescue Errno::ENOENT
+      Bundler.ui = ui
+      Bundler.ui.error "bundler: command not found: #{cmd}"
+      Bundler.ui.warn "Install missing gem executables with `bundle install`"
+      exit 127
+    end
+
+    def kernel_load(file, *args)
+      args.pop if args.last.is_a?(Hash)
+      ARGV.replace(args)
+      $0 = file
+      Process.setproctitle(process_title(file, args)) if Process.respond_to?(:setproctitle)
+      ui = Bundler.ui
+      Bundler.ui = nil
+      require "bundler/setup"
+      TRAPPED_SIGNALS.each {|s| trap(s, "DEFAULT") }
+      Kernel.load(file)
+    rescue SystemExit, SignalException
+      raise
+    rescue Exception => e # rubocop:disable Lint/RescueException
+      Bundler.ui = ui
+      Bundler.ui.error "bundler: failed to load command: #{cmd} (#{file})"
+      backtrace = e.backtrace ? e.backtrace.take_while {|bt| !bt.start_with?(__FILE__) } : []
+      abort "#{e.class}: #{e.message}\n  #{backtrace.join("\n  ")}"
+    end
+
+    def process_title(file, args)
+      "#{file} #{args.join(" ")}".strip
+    end
+
+    def ruby_shebang?(file)
+      possibilities = [
+        "#!/usr/bin/env ruby\n",
+        "#!/usr/bin/env jruby\n",
+        "#!/usr/bin/env truffleruby\n",
+        "#!#{Gem.ruby}\n",
+      ]
+
+      if File.zero?(file)
+        Bundler.ui.warn "#{file} is empty"
+        return false
+      end
+
+      first_line = File.open(file, "rb") {|f| f.read(possibilities.map(&:size).max) }
+      possibilities.any? {|shebang| first_line.start_with?(shebang) }
+    end
+  end
+end