Heroku - Precompiling assets failed. Push rejected, failed to compile Ruby app

Question

I'm a bit too new at RoR to spot where the error is. Been following railstutorial.org and I get this on my push to heroku.

Is it aborting because of this --> NoMethodError: undefined method `link_to' for .

?? That's the only thing that I was able to spot for myself.

 warning: push.default is unset; its implicit value is changing in
Git 2.0 from 'matching' to 'simple'. To squelch this message
and maintain the current behavior after the default changes, use:

  git config --global push.default matching

To squelch this message and adopt the new behavior now, use:

  git config --global push.default simple

See 'git help config' and search for 'push.default' for further information.
(the 'simple' mode was introduced in Git 1.7.11. Use the similar mode
'current' instead of 'simple' if you sometimes use older versions of Git)

Fetching repository, done.
Counting objects: 88, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (56/56), done.
Writing objects: 100% (62/62), 23.47 KiB | 0 bytes/s, done.
Total 62 (delta 25), reused 0 (delta 0)

-----> Removing .DS_Store files
-----> Ruby app detected
-----> Compiling Ruby/Rails
-----> Using Ruby version: ruby-2.0.0
-----> Installing dependencies using 1.5.2
       Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
       Fetching gem metadata from https://rubygems.org/..........
       Fetching additional metadata from https://rubygems.org/..
       Using rake (10.2.2)
       Using i18n (0.6.9)
       Using minitest (4.7.5)
       Using multi_json (1.9.2)
       Using atomic (1.1.16)
       Using tzinfo (0.3.39)
       Using builder (3.1.4)
       Using erubis (2.7.0)
       Using rack (1.5.2)
       Using mime-types (1.25.1)
       Using activerecord-deprecated_finders (1.0.3)
       Using polyglot (0.3.4)
       Using arel (4.0.2)
       Using sass (3.3.4)
       Using coffee-script-source (1.7.0)
       Using execjs (2.0.2)
       Using thor (0.19.1)
       Using hike (1.2.3)
       Using json (1.8.1)
       Using pg (0.15.1)
       Using bundler (1.5.2)
       Using tilt (1.4.1)
       Using rails_serve_static_assets (0.0.2)
       Using rails_stdout_logging (0.0.3)
       Using thread_safe (0.3.1)
       Using treetop (1.4.15)
       Using uglifier (2.1.1)
       Using rdoc (3.12.2)
       Using rails_12factor (0.0.2)
       Using activesupport (4.0.4)
       Using mail (2.5.4)
       Using sdoc (0.3.20)
       Using activemodel (4.0.4)
       Using jbuilder (1.0.2)
       Using rack-test (0.6.2)
       Using activerecord (4.0.4)
       Using actionpack (4.0.4)
       Using actionmailer (4.0.4)
       Using railties (4.0.4)
       Using jquery-rails (3.0.4)
       Using coffee-script (2.2.0)
       Using coffee-rails (4.0.1)
       Using turbolinks (1.1.1)
       Installing sprockets (2.11.0)
       Using sprockets-rails (2.0.1)
       Using rails (4.0.4)
       Using sass-rails (4.0.1)
       Installing bootstrap-sass (2.3.2.0)
       Your bundle is complete!
       Gems in the groups development and test were not installed.
       It was installed into ./vendor/bundle
       Bundle completed (8.36s)
       Cleaning up the bundler cache.
       Removing sprockets (2.12.0)
-----> Writing config/database.yml to read from DATABASE_URL
-----> Preparing app for Rails asset pipeline
       Running: rake assets:precompile
       I, [2014-05-08T09:29:54.385001 #707]  INFO -- : Writing /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/public/assets/rails-9526610ae44d9e73134fd4337d78a4bb.png
       I, [2014-05-08T09:29:59.414656 #707]  INFO -- : Writing /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/public/assets/application-354cc53e50f2562d96d57a34facbc739.js
       rake aborted!
       NoMethodError: undefined method `link_to' for #<#<Class:0x007f34511a3ad8>:0x007f34503d11f8>
       (in /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/app/assets/stylesheets/_footer.html.erb)
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/app/assets/stylesheets/_footer.html.erb:8:in `block in singleton class'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/app/assets/stylesheets/_footer.html.erb:-5:in `instance_eval'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/app/assets/stylesheets/_footer.html.erb:-5:in `singleton class'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/app/assets/stylesheets/_footer.html.erb:-7:in `__tilt_69931320843940'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/tilt-1.4.1/lib/tilt/template.rb:170:in `call'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/tilt-1.4.1/lib/tilt/template.rb:170:in `evaluate'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/tilt-1.4.1/lib/tilt/template.rb:103:in `render'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/context.rb:197:in `block in evaluate'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/context.rb:194:in `each'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/context.rb:194:in `evaluate'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/processed_asset.rb:12:in `initialize'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:374:in `new'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:374:in `block in build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:395:in `circular_call_protection'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:373:in `build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/index.rb:94:in `block in build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/caching.rb:58:in `cache_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/index.rb:93:in `build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:287:in `find_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/index.rb:61:in `find_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/bundled_asset.rb:16:in `initialize'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:377:in `new'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:377:in `build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/index.rb:94:in `block in build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/caching.rb:58:in `cache_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/index.rb:93:in `build_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:287:in `find_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/index.rb:61:in `find_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:211:in `block in find_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:257:in `benchmark'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:210:in `find_asset'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:119:in `block in compile'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:118:in `each'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:118:in `compile'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.1/lib/sprockets/rails/task.rb:60:in `block (3 levels) in define'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-2.11.0/lib/rake/sprocketstask.rb:146:in `with_logger'
       /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/vendor/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.1/lib/sprockets/rails/task.rb:59:in `block (2 levels) in define'
       Tasks: TOP => assets:precompile
       (See full trace by running task with --trace)
 !
 !     Precompiling assets failed.
 !

 !     Push rejected, failed to compile Ruby app

To git@heroku.com:vast-brushlands-3575.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git@heroku.com:vast-brushlands-3575.git'

Answer 1

Here's the error for your perusal:

NoMethodError: undefined method `link_to' for #<#<Class:0x007f34511a3ad8>:0x007f34503d11f8>
       (in /tmp/build_9f6acb94-a718-4de8-8d46-b7b035805102/app/assets/stylesheets/_footer.html.erb)

As @Merek has pointed out, you've got a _footer.html.erb file in your assets/stylesheets folder. As rake assets:precompile basically takes your CSS & turns it into precompiled code, it's saying it can't process link_to

Remove the file, recommit and re-push to Heroku. It should work, unless you've got other rouge files

Answer 2

Please Update Your WebPacker and Yarn with this command:

yarn upgrade @rails/webpacker --latest

`