Sprockets can't find `.jst.eco.erb` files

[divoxx]

Expected behavior

Template files with the .jst.eco.erb extensions should be properly located and loaded.

Actual behavior

Sprockets::FileNotFound: couldn't find file 'templates/foo' with type 'application/javascript'

System configuration

• Sprockets version 4 beta
• Ruby version 2.4

Example App

In this example app, a template plain.jst.eco loads fine but the erb.jst.eco.erb doesn't: https://github.com/divoxx/sprockets-test/blob/master/app/assets/javascripts/application.js#L17-L18

$ ./bin/rake assets:precompile
Running via Spring preloader in process 13359
rake aborted!
Sprockets::FileNotFound: couldn't find file 'templates/erb' with type 'application/javascript'
Checked in these paths: 
  /home/divoxx/Code/src/github.com/divoxx/sprockets-test/app/assets/config
  /home/divoxx/Code/src/github.com/divoxx/sprockets-test/app/assets/images
  /home/divoxx/Code/src/github.com/divoxx/sprockets-test/app/assets/javascripts
  /home/divoxx/Code/src/github.com/divoxx/sprockets-test/app/assets/stylesheets
  /home/divoxx/Code/src/github.com/divoxx/sprockets-test/vendor/assets/javascripts
  /home/divoxx/Code/src/github.com/divoxx/sprockets-test/vendor/assets/stylesheets
  /home/divoxx/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/jquery-rails-4.3.1/vendor/assets/javascripts
  /home/divoxx/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/coffee-rails-4.2.1/lib/assets/javascripts
  /home/divoxx/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/actioncable-5.0.2/lib/assets/compiled
  /home/divoxx/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/turbolinks-source-5.0.0/lib/assets/javascripts
/home/divoxx/Code/src/github.com/divoxx/sprockets-test/app/assets/config/manifest.js:2
/home/divoxx/Code/src/github.com/divoxx/sprockets-test/app/assets/javascripts/application.js:18
-e:1:in `<main>'
Tasks: TOP => assets:precompile
(See full trace by running task with --trace)

[stiller-leser]

I am seeing a similar issue with a *.js.jst.ejs.slim file. It tells me:

couldn't find file 'folder/name' with type 'application/javascript' Checked in these paths:

Could you add this to your pull request?

[schneems]

This is how erb is supported

  require 'sprockets/erb_processor'
  register_transformer_suffix(%w(
    application/ecmascript-6
    application/javascript
    application/json
    application/xml
    text/coffeescript
    text/css
    text/html
    text/plain
    text/sass
    text/scss
    text/yaml
  ), 'application/\2+ruby', '.erb', ERBProcessor)

It doesn't look like we're checking for eco files.

[divoxx]

@schneems there is a fix for it here: https://github.com/rails/sprockets/pull/491