Exception without manifest.js in 4.0.0

[olivierlacan]

Expected behavior

When no app/assets/config/manifest.js file, Sprockets should just warn that it's disabled or could not load, and not throw and error. Since our app doesn't include anything in app/assets, and only has Sprockets enabled for the same of the GraphiQL development interface (which does render views and assets but within a gem, not from our app). For this same reason we're not using config.api_only = true in config/application.rb because that would have disabled Sprockets and prevented this issue from occurring. I believe it's likely why few people caught this issue.

Actual behavior

An error is thrown since 4.0, this didn't occur on 3.7.2:

rake aborted!
  Sprockets::Railtie::ManifestNeededError: Expected to find a manifest file in `app/assets/config/manifest.js`
  But did not, please create this file and use it to link any assets that need
  to be rendered by your app:
  
  Example:
    //= link_tree ../images
    //= link_directory ../javascripts .js
    //= link_directory ../stylesheets .css
  and restart your server

System configuration

• Sprockets 4.0.0
• Ruby 2.5.7

[rafaelfranca]

How is the GraphiQL configuring sprockets? It should not be working if the application don't have a manifest because the application manifest need to tell sprockets to link the assets on engines.

[olivierlacan]

AFAIK it's not configuring anything, it just assumes require "sprockets/railtie" is called and mounts itself as a Rails engine.

https://github.com/rmosolgo/graphiql-rails/tree/5770e774f9da754aa8c1eee5651d6c663ca8e2a2/app/assets/javascripts/graphiql/rails
https://github.com/rmosolgo/graphiql-rails/blob/5770e774f9da754aa8c1eee5651d6c663ca8e2a2/config/routes.rb

[rafaelfranca]

oh! So I think it will not work anymore unless you add a manifest in your app you could try to remove the initializer that raises locally and see if the javascripts for graphiql are being rendered.

[vividtone]

Redmine 4.0 (<= 4.0.4) and 3.4 (<= 3.4.11) are also affected this issue.
https://www.redmine.org/issues/32300

I think sprockets 4.0.0 should not raise the error if asset pipeline is disabled (config.assets.enabled is set to false).
https://www.redmine.org/projects/redmine/repository/entry/tags/4.0.5/config/application.rb#L40

[rafaelfranca]

That is disabling assets compilation but not sprockets. If you want to disable sprockets you need to change the require 'rails/all' to require the individual railties and leave the sprockets railties out of the list.

[ashrafalzyoud]

its not working yet in Rev 18859
its give error in ASSET IN REDMINE 4.0.5

[ashrafalzyoud]

redmine@redmine:~/redmine-4.0$ bundle exec rake db:migrate RAILS_ENV=production rake aborted!
NoMethodError: undefined method assets' for #<Rails::Engine::Configuration:0x0000563025980d90> /home/redmine/redmine-4.0/config/application.rb:28:in <top (required)>'
/home/redmine/redmine-4.0/Rakefile:5:in require' /home/redmine/redmine-4.0/Rakefile:5:in <top (required)>'
/home/redmine/.rbenv/versions/2.5.5/bin/bundle:23:in load' /home/redmine/.rbenv/versions/2.5.5/bin/bundle:23:in

'
(See full trace by running task with --trace)

[ashrafalzyoud]

Redmine 4.0 (<= 4.0.4) and 3.4 (<= 3.4.11) are also affected this issue.
https://www.redmine.org/issues/32300

I think sprockets 4.0.0 should not raise the error if asset pipeline is disabled (config.assets.enabled is set to false).
https://www.redmine.org/projects/redmine/repository/entry/tags/4.0.5/config/application.rb#L40
redmine@redmine:~/redmine-4.0$ bundle exec rake db:migrate RAILS_ENV=production rake aborted!
NoMethodError: undefined method assets' for #<Rails::Engine::Configuration:0x0000563025980d90> /home/redmine/redmine-4.0/config/application.rb:28:in <top (required)>'
/home/redmine/redmine-4.0/Rakefile:5:in require' /home/redmine/redmine-4.0/Rakefile:5:in <top (required)>'
/home/redmine/.rbenv/versions/2.5.5/bin/bundle:23:in load' /home/redmine/.rbenv/versions/2.5.5/bin/bundle:23:in

'
(See full trace by running task with --trace)

[vividtone]

@ashrafalzyoud Could you open an issue on https://www.redmine.org/ ?

[rafaelfranca]

Closing since this isn't an issue. Sprockets 4 requires a manifest, of if you don't need sprockets remove it from the application.