"Any failure to compile resources will now cause the push request to fail. For information on supporting the resource pipeline in Rails 5, see the Ruby support page."
The Rails resource pipeline provides the rake "precompile asset" task, which allows you to compile and cache resources in advance, rather than compiling each time the application loads. There are two ways to use the asset pipeline on Heroku. Compiling resources locally. Compilation of assets during bullet compilation.
To compile your resources locally, run the assets: precompile task locally in your application. Make sure you use the production environment to create a working version of your assets.
Before you can compile your resources on Heroku, you need to be able to compile them locally, run this command to debug your resources:
RAILS_ENV=production bundle exec rake assets:precompile
This should complete without error. DO NOT check resources in git after running this command if using Rails 3 according to Heroku documentation.
A public directory / resource directory will be created. Inside this directory you will find a manifest.yml file that includes md5sums of compiled resources in Rails 3. In Rails 4, the file will be manifest-.json. Adding public / assets to your git repository will make it available to Heroku.
git add public/assets git commit -m "vendor compiled assets"'
Now, when clicked, the output should show that your locally compiled assets have been detected:
-----> Preparing Rails asset pipeline Detected manifest.yml, assuming assets were compiled locally
More help can be found here.
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