Ruby on Rails Rake assets:precompile error

Question

I\'m new in Rails development and this is my first deployment to Heroku. When I execute my application (after the deployment) there is an error:

2011-09-18T2         


        

Answer 1

I had the same error message. My issue was an incorrectly specified font url.

The bulk of this answer shows how I figured it out.

Although I didn't get the path of the asset it was failing on when running

RAILS_ENV=production SECRET_KEY_BASE=xxx rake assets:precompile --trace

Instead I had this stack trace:

** Invoke assets:precompile (first_time)
** Invoke assets:environment (first_time)
** Execute assets:environment
** Invoke environment (first_time)
** Execute environment
** Execute assets:precompile
rake aborted!
NoMethodError: undefined method `[]' for nil:NilClass
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_processor.rb:283:in `sprockets_context'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_processor.rb:124:in `asset_path'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_processor.rb:142:in `asset_url'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_processor.rb:214:in `font_url'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/script/tree/funcall.rb:143:in `_perform'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/script/tree/node.rb:58:in `perform'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/script/tree/list_literal.rb:63:in `block in _perform'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/script/tree/list_literal.rb:63:in `map'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/script/tree/list_literal.rb:63:in `_perform'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/script/tree/node.rb:58:in `perform'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:397:in `visit_prop'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:36:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:160:in `block in visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/stack.rb:79:in `block in with_base'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/stack.rb:115:in `with_frame'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/stack.rb:79:in `with_base'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:160:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:433:in `block (2 levels) in visit_rule'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:433:in `map'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:433:in `block in visit_rule'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:181:in `with_environment'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:431:in `visit_rule'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:36:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:160:in `block in visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/stack.rb:79:in `block in with_base'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/stack.rb:115:in `with_frame'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/stack.rb:79:in `with_base'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:160:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:52:in `block in visit_children'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:52:in `map'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:52:in `visit_children'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:169:in `block in visit_children'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:181:in `with_environment'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:168:in `visit_children'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:36:in `block in visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:188:in `visit_root'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/base.rb:36:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:159:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/visitors/perform.rb:8:in `visit'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/root_node.rb:36:in `css_tree'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/tree/root_node.rb:20:in `render'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sass-3.4.22/lib/sass/engine.rb:281:in `render'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_compressor.rb:48:in `call'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_compressor.rb:28:in `call'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/processor_utils.rb:75:in `call_processor'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/processor_utils.rb:57:in `block in call_processors'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/processor_utils.rb:56:in `reverse_each'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/processor_utils.rb:56:in `call_processors'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/loader.rb:134:in `load_from_unloaded'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/loader.rb:60:in `block in load'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/loader.rb:317:in `fetch_asset_from_dependency_cache'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/loader.rb:44:in `load'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/cached_environment.rb:20:in `block in initialize'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/cached_environment.rb:47:in `load'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/base.rb:66:in `find_asset'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/base.rb:73:in `find_all_linked_assets'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/manifest.rb:142:in `block in find'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/legacy.rb:114:in `block (2 levels) in logical_paths'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/path_utils.rb:228:in `block in stat_tree'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/path_utils.rb:212:in `block in stat_directory'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/path_utils.rb:209:in `each'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/path_utils.rb:209:in `stat_directory'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/path_utils.rb:227:in `stat_tree'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/legacy.rb:105:in `each'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/legacy.rb:105:in `block in logical_paths'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/legacy.rb:104:in `each'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/legacy.rb:104:in `logical_paths'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/manifest.rb:140:in `find'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/manifest.rb:185:in `compile'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-rails-3.1.1/lib/sprockets/rails/task.rb:68:in `block (3 levels) in define'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/rake/sprocketstask.rb:147:in `with_logger'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-rails-3.1.1/lib/sprockets/rails/task.rb:67:in `block (2 levels) in define'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/task.rb:248:in `block in execute'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/task.rb:243:in `each'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/task.rb:243:in `execute'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/task.rb:187:in `block in invoke_with_call_chain'
/Users/smithd98/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/monitor.rb:214:in `mon_synchronize'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/task.rb:180:in `invoke_with_call_chain'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/task.rb:173:in `invoke'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:152:in `invoke_task'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:108:in `block (2 levels) in top_level'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:108:in `each'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:108:in `block in top_level'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:117:in `run_with_threads'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:102:in `top_level'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:80:in `block in run'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:178:in `standard_exception_handling'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/lib/rake/application.rb:77:in `run'
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/rake-11.2.2/exe/rake:27:in `'
/Users/smithd98/.rvm/gems/ruby-2.3.1/bin/rake:23:in `load'
/Users/smithd98/.rvm/gems/ruby-2.3.1/bin/rake:23:in `
'
/Users/smithd98/.rvm/gems/ruby-2.3.1/bin/ruby_executable_hooks:15:in `eval'
/Users/smithd98/.rvm/gems/ruby-2.3.1/bin/ruby_executable_hooks:15:in `
'

I modified the gem to spit out the filename

subl /Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_processor.rb:124:in

like this

  def asset_path(path, options = {})
    path = path.value
    puts path
    puts '123'

    path, _, query, fragment = URI.split(path)[5..8]
    puts '126'
    path     = sprockets_context.asset_path(path, options)
    puts '128'
    query    = "?#{query}" if query
    puts '130'
    fragment = "##{fragment}" if fragment
    puts '132'
    Autoload::Sass::Script::String.new("#{path}#{query}#{fragment}", :string)
  end

Then when I ran

RAILS_ENV=production SECRET_KEY_BASE=xxx rake assets:precompile --trace

I got

** Invoke assets:precompile (first_time)
** Invoke assets:environment (first_time)
** Execute assets:environment
** Invoke environment (first_time)
** Execute environment
** Execute assets:precompile
fonts/OpenSans-Light.ttf
123
126
rake aborted!
NoMethodError: undefined method `[]' for nil:NilClass
/Users/smithd98/.rvm/gems/ruby-2.3.1/gems/sprockets-3.7.0/lib/sprockets/sass_processor.rb:283:in `sprockets_context'
...the rest of the stack trace is the same...

Then I found out the issue was a font had been specified like this:

.btn-rect {
  font-family: 'OpenSans-Light';
  src:font-url('fonts/OpenSans-Light.ttf') format('truetype');
}

and should have been like this:

.btn-rect {
  font-family: 'OpenSans-Light';
}