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/resolver/spec_group.rb

@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+module Bundler
+  class Resolver
+    class SpecGroup
+      include GemHelpers
+
+      attr_accessor :name, :version, :source
+      attr_accessor :ignores_bundler_dependencies
+
+      def initialize(all_specs)
+        raise ArgumentError, "cannot initialize with an empty value" unless exemplary_spec = all_specs.first
+        @name = exemplary_spec.name
+        @version = exemplary_spec.version
+        @source = exemplary_spec.source
+
+        @activated_platforms = []
+        @dependencies = nil
+        @specs        = Hash.new do |specs, platform|
+          specs[platform] = select_best_platform_match(all_specs, platform)
+        end
+        @ignores_bundler_dependencies = true
+      end
+
+      def to_specs
+        @activated_platforms.map do |p|
+          next unless s = @specs[p]
+          lazy_spec = LazySpecification.new(name, version, s.platform, source)
+          lazy_spec.dependencies.replace s.dependencies
+          lazy_spec
+        end.compact
+      end
+
+      def activate_platform!(platform)
+        return unless for?(platform)
+        return if @activated_platforms.include?(platform)
+        @activated_platforms << platform
+      end
+
+      def for?(platform)
+        spec = @specs[platform]
+        !spec.nil?
+      end
+
+      def to_s
+        @to_s ||= "#{name} (#{version})"
+      end
+
+      def dependencies_for_activated_platforms
+        dependencies = @activated_platforms.map {|p| __dependencies[p] }
+        metadata_dependencies = @activated_platforms.map do |platform|
+          metadata_dependencies(@specs[platform], platform)
+        end
+        dependencies.concat(metadata_dependencies).flatten
+      end
+
+      def ==(other)
+        return unless other.is_a?(SpecGroup)
+        name == other.name &&
+          version == other.version &&
+          source == other.source
+      end
+
+      def eql?(other)
+        name.eql?(other.name) &&
+          version.eql?(other.version) &&
+          source.eql?(other.source)
+      end
+
+      def hash
+        to_s.hash ^ source.hash
+      end
+
+    private
+
+      def __dependencies
+        @dependencies = Hash.new do |dependencies, platform|
+          dependencies[platform] = []
+          if spec = @specs[platform]
+            spec.dependencies.each do |dep|
+              next if dep.type == :development
+              next if @ignores_bundler_dependencies && dep.name == "bundler".freeze
+              dependencies[platform] << DepProxy.new(dep, platform)
+            end
+          end
+          dependencies[platform]
+        end
+      end
+
+      def metadata_dependencies(spec, platform)
+        return [] unless spec
+        # Only allow endpoint specifications since they won't hit the network to
+        # fetch the full gemspec when calling required_ruby_version
+        return [] if !spec.is_a?(EndpointSpecification) && !spec.is_a?(Gem::Specification)
+        dependencies = []
+        if !spec.required_ruby_version.nil? && !spec.required_ruby_version.none?
+          dependencies << DepProxy.new(Gem::Dependency.new("ruby\0", spec.required_ruby_version), platform)
+        end
+        if !spec.required_rubygems_version.nil? && !spec.required_rubygems_version.none?
+          dependencies << DepProxy.new(Gem::Dependency.new("rubygems\0", spec.required_rubygems_version), platform)
+        end
+        dependencies
+      end
+    end
+  end
+end