Heroku: Error encountered while saving cache

Question

Everything works fine locally, but when pushing to Heroku:

   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/bc1b787c8640c68bf42fc69efbef227d36428060/_carousel.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/bc1b787c8640c68bf42fc69efbef227d36428060/_hero-unit.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/bc1b787c8640c68bf42fc69efbef227d36428060/_utilities.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/exams.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/home.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/lessons.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/questions.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/scaffolds.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
   Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/sections.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>

Eventually I get:

   Warning. Error encountered while saving cache /tmp/build_ccaceaf0-2d8f-4d84-8284-9f5fcb7ced3f/tmp/cache/sass/6b13061e65d1f1cd905accb7f7211a333a70c956/sections.css.scssc: can't dump anonymous class #<Class:0x007f02dbceaa88>
   DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /tmp/build_ccaceaf0-2d8f-4d84-8284-9f5fcb7ced3f/Rakefile:7)
   DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /tmp/build_ccaceaf0-2d8f-4d84-8284-9f5fcb7ced3f/Rakefile:7)

 !     Timed out compiling Ruby app (15 minutes)
 !     See https://devcenter.heroku.com/articles/slug-compiler#time-limit

I've only pasted a fraction of the number of times this appears.

My gemfile:

ruby '2.0.0'
gem 'rails', '3.2.11'
group :assets do
  gem 'sass-rails' #,   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'
  gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
gem 'bootstrap-sass'#, '2.3.2.0'
gem 'cancan'
gem 'devise'
gem 'figaro'
gem 'haml-rails'
gem 'mongoid'
gem 'rolify'
gem 'simple_form'
gem 'thin'
gem 'country_select'
group :development do
  gem 'better_errors'
  gem 'binding_of_caller', :platforms=>[:mri_19, :rbx]
  gem 'guard-bundler'
  gem 'guard-rails'
  gem 'guard-rspec'
  gem 'html2haml'
  gem 'quiet_assets'
  gem 'rb-fchange', :require=>false
  gem 'rb-fsevent', :require=>false
  gem 'rb-inotify', :require=>false
  gem "switch_user"
end
group :development, :test do
  gem 'factory_girl_rails'
  gem 'rspec-rails'
end
group :test do
  gem 'database_cleaner'
  gem 'email_spec'
  gem 'mongoid-rspec'
end
gem "ckeditor"
#gem "binding_of_caller"
gem "mongoid-paperclip", :require => "mongoid_paperclip", :git=>'https://github.com/meskyanichi/mongoid-paperclip'
gem 'aws-sdk', '~> 1.3.4'
gem "flat-ui-rails"
gem 'stripe', :git => 'https://github.com/stripe/stripe-ruby'
gem "mongoid_slug", "~> 2.0.1"

My production.rb file has the following properties enabled

  config.cache_classes = true

  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true

  config.serve_static_assets = true

  config.assets.compress = true
  config.assets.compile = false

  config.assets.digest = true
  config.assets.initialize_on_precompile = false

My rails version is Rails 3.2.11

Answer 1

First you might want to update

bundle update sass-rails
bundle update sass

Then the more critical part (make sure you uninstall the sass version in your Gemfile.lock)

gem uninstall sass
bundle install

Answer 2

This is a known bug in Sass 3.3.0, the Sprockets importer is unserialized and so un-cacheable causing this error. For the bug report see this. Without the caching, Sass compiles excruciatingly slow which leads to the timeout on heroku servers.

Answer 3

This is related to the recent upgrade of the sass gem to 3.3.0. The sass gem is a dependency of a couple of other sass gems, so even if you don't have it in your Gemfile, it is probably getting loaded. Do a "bundle show" locally and on Heroku and I'm fairly sure you'll see they are different versions (sass was upgraded to 3.3.0 just a couple days ago).

Add:

gem 'sass', '3.2.13'

to your Gemfile and that should fix things for you. Then go submit an issue on github for this gem.

Hope this helps, it worked for me!