我尝试按照这个railscast将我的 3.0.10 rails 应用程序迁移到 3.1.10，但对我来说事情并没有像 Ryan 那样顺利。在解决了一些 gemset 依赖问题之后，我现在在尝试启动开发服务器时遇到了以下错误：
[nw0.0.1master (migrate_to_31)]$ rails s
=> Booting WEBrick
=> Rails 3.1.10 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.8.7/lib/rake.rb:2503:in `const_missing': uninitialized constant Sass::Plugin (NameError)
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/aws-s3-0.6.3/lib/aws/s3/extensions.rb:212:in `const_missing_from_s3_library'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config/initializers/active_admin.rb:2:in `<top (required)>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/engine.rb:556:in `block (2 levels) in <class:Engine>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/engine.rb:555:in `each'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/engine.rb:555:in `block in <class:Engine>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:30:in `instance_exec'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:30:in `run'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:55:in `block in run_initializers'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:54:in `each'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:54:in `run_initializers'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/application.rb:96:in `initialize!'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config/environment.rb:7:in `<top (required)>'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config.ru:3:in `block in <main>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:51:in `instance_eval'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:51:in `initialize'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config.ru:in `new'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config.ru:in `<main>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:40:in `eval'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:40:in `parse_file'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/server.rb:200:in `app'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands/server.rb:46:in `app'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/server.rb:304:in `wrapped_app'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/server.rb:254:in `start'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands/server.rb:70:in `start'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands.rb:54:in `block in <top (required)>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands.rb:49:in `tap'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands.rb:49:in `<top (required)>'
from script/rails:37:in `require'
from script/rails:37:in `<main>'
这是我当前的 Gemfile：
gem "pg"
gem 'pg_search'
gem 'rails', '3.1.10'
gem 'nokogiri', '1.5.5'
gem 'geocoder', '1.0.2'
gem 'devise', '1.5.3'
gem 'acts_as_api', '0.3.8'
gem 'paperclip', '~>2.4.1'
gem 'rake', '0.8.7'
gem 'omniauth', :git => 'https://github.com/intridea/omniauth.git'
gem 'fb_graph', '1.9.5'
gem 'twitter', :git => 'https://github.com/sferik/twitter.git'
gem 'jquery-rails', '>= 1.0.12'
gem 'aws-s3'
gem 'remotipart', '~> 1.0'
gem 'activeadmin'
gem 'formtastic', '~> 2.1.0'
gem "browser"
gem "httparty"
gem "thin"
# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem 'sass-rails', " ~> 3.1.0"
gem 'coffee-rails', "~> 3.1.0"
gem 'uglifier'
end
group :production, :staging do
end
group :development do
gem 'rspec-rails'
gem 'annotate', '2.4.0'
gem 'faker', '0.3.1'
gem 'ruby-debug19', '0.11.6'
gem 'nifty-generators', '0.4.6'
gem 'silent-postgres'
end
group :test do
gem 'rspec'
gem 'webrat', '0.7.1'
gem 'factory_girl_rails'
gem "mocha", '0.9.12'
gem 'silent-postgres'
end
而且，我在 application.rb 中启用了资产管道。这是application.rb：
require File.expand_path('../boot', __FILE__)
require 'rails/all'
# If you precompile assets before deploying to production, use this line
Bundler.require *Rails.groups(:assets => %w(development test))
# If you want your assets lazily compiled in production, use this line
# Bundler.require(:default, :assets, Rails.env)
module Nw001
class Application < Rails::Application
# Enable the asset pipeline
config.assets.enabled = true
# Version of your assets, change this if you want to expire all your assets
config.assets.version = '1.0'
# Settings in config/environments/* take precedence over those specified here.
# Application configuration should go into files in config/initializers
# -- all .rb files in that directory are automatically loaded.
# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)
# Only load the plugins named here, in the order given (default is alphabetical).
# :all can be used as a placeholder for all plugins not explicitly named.
# config.plugins = [ :exception_notification, :ssl_requirement, :all ]
# Activate observers that should always be running.
# config.active_record.observers = :cacher, :garbage_collector, :forum_observer
# Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
# Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
# config.time_zone = 'Central Time (US & Canada)'
# The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
# config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
# config.i18n.default_locale = :de
# JavaScript files you want as :defaults (application.js is always included).
# config.action_view.javascript_expansions[:defaults] = %w(jquery rails)
# Configure the default encoding used in templates for Ruby 1.9.
config.encoding = "utf-8"
# Configure sensitive parameters which will be filtered from the log file.
config.filter_parameters += [:password]
# Use SQL instead of Active Record's schema dumper when creating the database.
# This is necessary if your schema can't be completely dumped by the schema dumper,
# like if you have constraints or database-specific column types
# Note, the migration that I use to install the unaccented module for pgs requires SQL
# config.active_record.schema_format = :sql
#uncomment to force ssl on localhost
# config.middleware.insert_before ActionDispatch::Static, "Rack::SSL"
end
end
并且，对我的配置/环境文件进行了建议的添加。
知道如何通过未初始化的常量 Sass::Plugin (NameError) 吗？？？
我也尝试过使用 rails 3.1.0，它会抛出同样的错误。我也跑去rails generate active_admin:assets更新 active_admin 资产，但没有爱。
更新
在@andrew 的建议下，我创建了一个新的示例 rails3.1.10 应用程序。实际上，我所做的只是删除了我之前的 3.1 gemset；使用 rvm 创建一个新的 gemset；将 rails 3.1.10 安装到新的 gemset 中；开始使用新的 3.1 gemset；然后创建了一个新的 rails 3.1.10 应用程序。该应用程序按预期运行。
然后，我更进一步，将新应用程序 gemfile 替换为我尝试迁移到 3.1.10 的应用程序中的 gemfile。在解决了几个依赖问题并将 sqlite3 gem 重新插入 gemfile 之后，新的测试应用程序再次按预期运行。
然后，我将测试应用程序的 gemfile 复制回我尝试迁移的应用程序中，并且仍然使用新的 3.1 gemset，尝试加载开发服务器。我仍然得到一个错误，它与上面列出的错误相似，但有些不同。看看这个：
[nw0.0.1master (master)]$ rails s
=> Booting WEBrick
=> Rails 3.1.10 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/aws-s3-0.6.3/lib/aws/s3/extensions.rb:212:in `const_missing_from_s3_library': uninitialized constant Sass::Plugin (NameError)
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config/initializers/active_admin.rb:2:in `<top (required)>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/engine.rb:556:in `block (2 levels) in <class:Engine>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/engine.rb:555:in `each'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/engine.rb:555:in `block in <class:Engine>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:30:in `instance_exec'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:30:in `run'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:55:in `block in run_initializers'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:54:in `each'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/initializable.rb:54:in `run_initializers'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/application.rb:96:in `initialize!'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config/environment.rb:7:in `<top (required)>'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config.ru:3:in `block in <main>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:51:in `instance_eval'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:51:in `initialize'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config.ru:in `new'
from /Users/charlesweinberger/rails_projects/nw0.0.1master/config.ru:in `<main>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:40:in `eval'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/builder.rb:40:in `parse_file'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/server.rb:200:in `app'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands/server.rb:46:in `app'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/server.rb:304:in `wrapped_app'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/rack-1.3.8/lib/rack/server.rb:254:in `start'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands/server.rb:70:in `start'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands.rb:54:in `block in <top (required)>'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands.rb:49:in `tap'
from /Users/charlesweinberger/.rvm/gems/ruby-1.9.2-p290@rails31/gems/railties-3.1.10/lib/rails/commands.rb:49:in `<top (required)>'
from script/rails:37:in `require'
from script/rails:37:in `<main>'
这个新信息会触发任何想法吗？？？谢谢！