make all rails commands work in engine

Currently, all rails commands can be executed in engine,
but `server`, `console`, `dbconsole` and `runner` do not work.

This make all rails commands work in engine.
Related to #22588

9 files changed, 121 insertions, 51 deletions

diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index 6cb88ca01d..b2208193d2 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Make every Rails command work within engines.
+
+    *Sean Collins*, *Yuji Yaginuma*
+
 *   Don't generate HTML/ERB templates for scaffold controller with `--api` flag.
 
     Fixes #27591.
diff --git a/railties/lib/rails/command/actions.rb b/railties/lib/rails/command/actions.rb
index 31b656ec31..fb80e9d997 100644
--- a/railties/lib/rails/command/actions.rb
+++ b/railties/lib/rails/command/actions.rb
@@ -11,6 +11,11 @@ module Rails
       if defined?(ENGINE_PATH)
         def require_application_and_environment!
           require ENGINE_PATH
+
+          if defined?(APP_PATH)
+            require APP_PATH
+            Rails.application.require_environment!
+          end
         end
 
         def load_tasks
diff --git a/railties/lib/rails/commands/help/USAGE b/railties/lib/rails/commands/help/USAGE
index 348f41861f..c5f8ab72bb 100644
--- a/railties/lib/rails/commands/help/USAGE
+++ b/railties/lib/rails/commands/help/USAGE
@@ -1,16 +1,3 @@
-Usage: bin/rails COMMAND [args] [options]
-<% if engine? %>
-The common Rails commands available for engines are:
- generate    Generate new code (short-cut alias: "g")
- destroy     Undo code generated with "generate" (short-cut alias: "d")
- test        Run tests (short-cut alias: "t")
-
-All commands can be run with -h for more information.
-
-If you want to run any commands that need to be run in context
-of the application, like `bin/rails server` or `bin/rails console`,
-you should do it from the application's directory (typically test/dummy).
-<% else %>
 The most common rails commands are:
  generate    Generate new code (short-cut alias: "g")
  console     Start the Rails console (short-cut alias: "c")
@@ -18,10 +5,11 @@ The most common rails commands are:
  test        Run tests (short-cut alias: "t")
  dbconsole   Start a console for the database specified in config/database.yml
              (short-cut alias: "db")
+<% unless engine? %>
  new         Create a new Rails application. "rails new my_app" creates a
              new application called MyApp in "./my_app"
+<% end %>
 
 All commands can be run with -h (or --help) for more information.
-<% end %>
 In addition to those commands, there are:
 
diff --git a/railties/lib/rails/commands/server/server_command.rb b/railties/lib/rails/commands/server/server_command.rb
index 15c636103b..d58721f648 100644
--- a/railties/lib/rails/commands/server/server_command.rb
+++ b/railties/lib/rails/commands/server/server_command.rb
@@ -95,7 +95,7 @@ module Rails
 
   module Command
     class ServerCommand < Base # :nodoc:
-      DEFAULT_PID_PATH = File.expand_path("tmp/pids/server.pid").freeze
+      DEFAULT_PID_PATH = "tmp/pids/server.pid".freeze
 
       class_option :port, aliases: "-p", type: :numeric,
         desc: "Runs Rails on the specified port.", banner: :port, default: 3000
@@ -141,7 +141,7 @@ module Rails
             config:             options[:config],
             environment:        environment,
             daemonize:          options[:daemon],
-            pid:                options[:pid],
+            pid:                pid,
             caching:            options["dev-caching"],
             restart_cmd:        restart_command
           }
@@ -165,6 +165,10 @@ module Rails
           "bin/rails server #{@server} #{@original_options.join(" ")}"
         end
 
+        def pid
+          File.expand_path(options[:pid])
+        end
+
         def self.banner(*)
           "rails server [puma, thin etc] [options]"
         end
diff --git a/railties/lib/rails/engine/commands.rb b/railties/lib/rails/engine/commands.rb
index a23ae44b0b..b9ef63243a 100644
--- a/railties/lib/rails/engine/commands.rb
+++ b/railties/lib/rails/engine/commands.rb
@@ -1,12 +1,7 @@
-require "rails/command"
+unless defined?(APP_PATH)
+  if File.exist?(File.expand_path("test/dummy/config/application.rb", ENGINE_ROOT))
+    APP_PATH = File.expand_path("test/dummy/config/application", ENGINE_ROOT)
+  end
+end
 
-aliases = {
-  "g" => "generate",
-  "d" => "destroy",
-  "t" => "test"
-}
-
-command = ARGV.shift
-command = aliases[command] || command
-
-Rails::Command.invoke command, ARGV
+require "rails/commands"
diff --git a/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt b/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt
index 56e7925c6b..c03d9953d4 100644
--- a/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt
+++ b/railties/lib/rails/generators/rails/plugin/templates/bin/rails.tt
@@ -3,6 +3,7 @@
 
 ENGINE_ROOT = File.expand_path('../..', __FILE__)
 ENGINE_PATH = File.expand_path('../../lib/<%= namespaced_name -%>/engine', __FILE__)
+APP_PATH = File.expand_path('../../<%= dummy_path -%>/config/application', __FILE__)
 
 # Set up gems listed in the Gemfile.
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__)
diff --git a/railties/test/engine/commands_tasks_test.rb b/railties/test/engine/commands_tasks_test.rb
deleted file mode 100644
index 817175b9ef..0000000000
--- a/railties/test/engine/commands_tasks_test.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-require "abstract_unit"
-
-class Rails::Engine::CommandsTasksTest < ActiveSupport::TestCase
-  def setup
-    @destination_root = Dir.mktmpdir("bukkits")
-    Dir.chdir(@destination_root) { `bundle exec rails plugin new bukkits --mountable` }
-  end
-
-  def teardown
-    FileUtils.rm_rf(@destination_root)
-  end
-
-  def test_help_command_work_inside_engine
-    output = capture(:stderr) do
-      Dir.chdir(plugin_path) { `bin/rails --help` }
-    end
-    assert_no_match "NameError", output
-  end
-
-  private
-    def plugin_path
-      "#{@destination_root}/bukkits"
-    end
-end
diff --git a/railties/test/engine/commands_test.rb b/railties/test/engine/commands_test.rb
new file mode 100644
index 0000000000..b1c937143f
--- /dev/null
+++ b/railties/test/engine/commands_test.rb
@@ -0,0 +1,96 @@
+require "abstract_unit"
+begin
+  require "pty"
+rescue LoadError
+end
+
+class Rails::Engine::CommandsTest < ActiveSupport::TestCase
+  def setup
+    @destination_root = Dir.mktmpdir("bukkits")
+    Dir.chdir(@destination_root) { `bundle exec rails plugin new bukkits --mountable` }
+  end
+
+  def teardown
+    FileUtils.rm_rf(@destination_root)
+  end
+
+  def test_help_command_work_inside_engine
+    output = capture(:stderr) do
+      Dir.chdir(plugin_path) { `bin/rails --help` }
+    end
+    assert_no_match "NameError", output
+  end
+
+  def test_runner_command_work_inside_engine
+    output = capture(:stdout) do
+      Dir.chdir(plugin_path) { system("bin/rails runner 'puts Rails.env'") }
+    end
+
+    assert_equal "test", output.strip
+  end
+
+  def test_console_command_work_inside_engine
+    skip "PTY unavailable" unless available_pty?
+
+    master, slave = PTY.open
+    spawn_command("console", slave)
+    assert_output(">", master)
+  ensure
+    master.puts "quit"
+  end
+
+  def test_dbconsole_command_work_inside_engine
+    skip "PTY unavailable" unless available_pty?
+
+    master, slave = PTY.open
+    spawn_command("dbconsole", slave)
+    assert_output("sqlite>", master)
+  ensure
+    master.puts ".exit"
+  end
+
+  def test_server_command_work_inside_engine
+    skip "PTY unavailable" unless available_pty?
+
+    master, slave = PTY.open
+    pid = spawn_command("server", slave)
+    assert_output("Listening on", master)
+  ensure
+    kill(pid)
+  end
+
+  private
+    def plugin_path
+      "#{@destination_root}/bukkits"
+    end
+
+    def assert_output(expected, io, timeout = 10)
+      timeout = Time.now + timeout
+
+      output = ""
+      until output.include?(expected) || Time.now > timeout
+        if IO.select([io], [], [], 0.1)
+          output << io.read(1)
+        end
+      end
+
+      assert_includes output, expected, "#{expected.inspect} expected, but got:\n\n#{output}"
+    end
+
+    def spawn_command(command, fd)
+      Process.spawn(
+        "#{plugin_path}/bin/rails #{command}",
+        in: fd, out: fd, err: fd
+      )
+    end
+
+    def available_pty?
+      defined?(PTY) && PTY.respond_to?(:open)
+    end
+
+    def kill(pid)
+      Process.kill("TERM", pid)
+      Process.wait(pid)
+    rescue Errno::ESRCH
+    end
+end
diff --git a/railties/test/generators/plugin_generator_test.rb b/railties/test/generators/plugin_generator_test.rb
index 9921a80342..ddfbc1a698 100644
--- a/railties/test/generators/plugin_generator_test.rb
+++ b/railties/test/generators/plugin_generator_test.rb
@@ -421,6 +421,7 @@ class PluginGeneratorTest < Rails::Generators::TestCase
     run_generator [destination_root, "--full"]
     assert_file "bin/rails", /ENGINE_PATH = File.expand_path\('..\/..\/lib\/bukkits\/engine', __FILE__\)/
     assert_file "bin/rails", /ENGINE_ROOT = File.expand_path\('..\/..', __FILE__\)/
+    assert_file "bin/rails", %r|APP_PATH = File.expand_path\('../../test/dummy/config/application', __FILE__\)|
     assert_file "bin/rails", /require 'rails\/all'/
     assert_file "bin/rails", /require 'rails\/engine\/commands'/
   end