Merge bundler to standard libraries.

rubygems 2.7.x depends bundler-1.15.x. This is preparation for
  rubygems and bundler migration.

  * lib/bundler.rb, lib/bundler/*: files of bundler-1.15.4
  * spec/bundler/*: rspec examples of bundler-1.15.4. I applied patches.
    * https://github.com/bundler/bundler/pull/6007
    * Exclude not working examples on ruby repository.
    * Fake ruby interpriter instead of installed ruby.
  * Makefile.in: Added test task named `test-bundler`. This task is only
    working macOS/linux yet. I'm going to support Windows environment later.
  * tool/sync_default_gems.rb: Added sync task for bundler.

  [Feature #12733][ruby-core:77172]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59779 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/bundler/cli/info.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+require "bundler/cli/common"
+
+module Bundler
+  class CLI::Info
+    attr_reader :gem_name, :options
+    def initialize(options, gem_name)
+      @options = options
+      @gem_name = gem_name
+    end
+
+    def run
+      spec = spec_for_gem(gem_name)
+
+      spec_not_found(gem_name) unless spec
+      return print_gem_path(spec) if @options[:path]
+      print_gem_info(spec)
+    end
+
+  private
+
+    def spec_for_gem(gem_name)
+      spec = Bundler.definition.specs.find {|s| s.name == gem_name }
+      spec || default_gem_spec(gem_name)
+    end
+
+    def default_gem_spec(gem_name)
+      return unless Gem::Specification.respond_to?(:find_all_by_name)
+      gem_spec = Gem::Specification.find_all_by_name(gem_name).last
+      return gem_spec if gem_spec && gem_spec.respond_to?(:default_gem?) && gem_spec.default_gem?
+    end
+
+    def spec_not_found(gem_name)
+      raise GemNotFound, Bundler::CLI::Common.gem_not_found_message(gem_name, Bundler.definition.dependencies)
+    end
+
+    def print_gem_path(spec)
+      Bundler.ui.info spec.full_gem_path
+    end
+
+    def print_gem_info(spec)
+      gem_info = String.new
+      gem_info << "  * #{spec.name} (#{spec.version}#{spec.git_version})\n"
+      gem_info << "\tSummary: #{spec.summary}\n" if spec.summary
+      gem_info << "\tHomepage: #{spec.homepage}\n" if spec.homepage
+      gem_info << "\tPath: #{spec.full_gem_path}\n"
+      gem_info << "\tDefault Gem: yes" if spec.respond_to?(:default_gem?) && spec.default_gem?
+      Bundler.ui.info gem_info
+    end
+  end
+end