TLDR：在另一个模型文件中使用require 'classname'（因此我可以反序列化一个列）在本地工作，但在部署到Heroku时会导致No such file to load -- Classname错误。
我做出了一个不可思议的设计决定，即序列化一个模型属性，该属性包含另一个模型对象的数组（UserCategoryQueue有一个Card个对象的序列化队列。为了实际反序列化这些对象，我遵循YAML::load raises undefined class/module error中的建议在我需要反序列化该列的文件中使用require 'Card'。这避免了YAML在到达Card对象时不知道它在看什么的问题。
这在localhost服务器上工作正常但在部署到Heroku时导致了很多问题，所有形式都是No such file to load -- Card"。最初，这发生在资产预编译阶段，然后我自己预编译资产，当我尝试运行$ heroku run rake db:migrate以首次设置所有内容时，同样的错误已经移动。
示例文件：
# app/models/user_category_queue.rb
class UserCategoryQueue < ActiveRecord::Base
...
# Our queue of Cards
serialize :queue, Array
end
# app/models/quiz.rb
class Quiz < ActiveRecord::Base
...
require 'Card'
...
# grab a random card from the user's queues
# produces YAML error without the above require statement
def sample_card
self.user.user_category_queues.sample.queue.sample
end
end
这最终导致推送到Heroku时出现以下错误（在我尝试任何资产预编译之前）：
Running: rake assets:precompile rake aborted! No such file to load -- Card /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `block in require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/app/models/quiz.rb:18:in `<class:Quiz>' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/app/models/quiz.rb:1:in `<top (required)>' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `block in require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:329:in `require_or_load' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:288:in `depend_on' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:206:in `require_dependency' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/engine.rb:465:in `block (2 levels) in eager_load!' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/engine.rb:464:in `each' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/engine.rb:464:in `block in eager_load!' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/engine.rb:462:in `each' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/engine.rb:462:in `eager_load!' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/engine.rb:347:in `eager_load!' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application/finisher.rb:56:in `each' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application/finisher.rb:56:in `block in <module:Finisher>' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:30:in `instance_exec' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:30:in `run' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:55:in `block in run_initializers' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/initializable.rb:54:in `run_initializers' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application.rb:215:in `initialize!' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/railtie/configurable.rb:30:in `method_missing' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/config/environment.rb:5:in `<top (required)>' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `block in require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application.rb:189:in `require_environment!' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0/lib/rails/application.rb:249:in `block in run_tasks_blocks' /tmp/build_d0e6e2b8-a3fd-4a90-ae44-e703b0093401/vendor/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0/lib/sprockets/rails/task.rb:54:in `block (2 levels) in define' Tasks: TOP => environment (See full trace by running task with --trace)！ ！预编译资产失败。
正如我所说，即使预编译资产，虽然推送顺利，但随后的数据库迁移也会弹出相同的错误。
答案 0 :(得分：0)
Heroku运行区分大小写的文件系统，而您的操作系统可能不区分大小写。请尝试更改此要求：
require 'card'
作为一般的经验法则，Ruby中的大多数文件都需要使用带有下划线的小写字母作为单词分隔符，如下所示：
require 'card_shuffler'