How to exclude assets from gems/engines? Known approach looks tedious or like a hack

[tmaier]

I want to exclude all assets I am not using from precompiling.
I understand that config.assets.excluded_paths exists and that it requires a full path.

In my case Rails.application.config.assets.paths returns

["/usr/src/app/app/assets/builds",
 "/usr/src/app/app/assets/images",
 "/usr/local/bundle/gems/view_component-2.53.0/app/assets/vendor",
 "/usr/local/bundle/gems/unobtrusive_flash-3.3.1/lib/assets/javascripts",
 "/usr/local/bundle/gems/unobtrusive_flash-3.3.1/lib/assets/stylesheets",
 "/usr/local/bundle/gems/turbo-rails-1.0.1/app/assets/javascripts",
 "/usr/local/bundle/gems/nested_form-0.3.2/vendor/assets/javascripts",
 "/usr/local/bundle/gems/heroicon-0.4.0/app/assets/images",
 "/usr/local/bundle/gems/actioncable-7.0.2.3/app/assets/javascripts",
 "/usr/local/bundle/gems/actionview-7.0.2.3/lib/assets/compiled"]

I would like to exclude most of them, e.g. "/usr/local/bundle/gems/nested_form-0.3.2/vendor/assets/javascripts" or "/usr/local/bundle/gems/actionview-7.0.2.3/lib/assets/compiled".

I have two reasons for this: It takes comparatively long (e.g. assets from heroicon), I don't like to waste space (I know, it is not too much) and I like to have a clean directory with only the files I really use.

This is the only way I found to do so:

Rails.application.config.assets.excluded_paths << File.join(Heroicon.root, 'app/assets/images')
# rubocop:disable Style/StringConcatenation
Rails.application.config.assets.excluded_paths << (Pathname.new(Gem.find_files_from_load_path('nested_form').first) + '../../vendor/assets/javascripts')
Rails.application.config.assets.excluded_paths << (Pathname.new(Gem.find_files_from_load_path('turbo-rails').first) + '../../app/assets/javascripts')
Rails.application.config.assets.excluded_paths << (Pathname.new(Gem.find_files_from_load_path('unobtrusive_flash').first) + '../../lib/assets/stylesheets')
Rails.application.config.assets.excluded_paths << (Pathname.new(Gem.find_files_from_load_path('unobtrusive_flash').first) + '../../lib/assets/javascripts')
Rails.application.config.assets.excluded_paths << (Pathname.new(Gem.find_files_from_load_path('view_component').first) + '../../app/assets/vendor')
# rubocop:enable Style/StringConcatenation

Note: I am unable to use this methodology to exclude actionview or actioncable.

Pathname.new(Gem.find_files_from_load_path('whaever').first) does not look like a good solution

What is the recommended way?
How can this be simplified?

[kevynlebouille]

Hi @tmaier ,

I saw something in turbo-rail repo like that (put in your application.rb for instance)

config.after_initialize do
  config.assets.precompile -= Turbo::Engine::PRECOMPILE_ASSETS
end

You could use the same approach for anything come from another gem.

Kevyn

[tmaier]

Thanks @kevynlebouille,

I think this does not work for Propshaft, as assets.precompile only exists for compatibility reasons. See

propshaft/lib/propshaft/railtie.rb

Line 62 in a4ddf9a

config.assets.precompile = []

Turbo::Engine::PRECOMPILE_ASSETS seems also just have the file names, not the path. See https://github.com/hotwired/turbo-rails/blob/6958e0e2742d4744da80128d178e7255989386a4/lib/turbo/engine.rb#L29

[haberbyte]

May not be ideal, but I used this workaround:

# config/initializers/assets.rb
Rails.application.config.after_initialize do |app|
    app.config.assets.paths = %w(
      app/assets/builds
      app/assets/config
      app/assets/images
    )
end

[brenogazzola]

We are currently taking a look at how we handle paths due to a caching bug and will take a look at this after we handle that.

[bjorntrondsen]

I was looking into how I can exclude assets not in use today and an approach based on Gem.loaded_specs seems to work

%w[actiontext activestorage actioncable actionview].each do |gem_name|
  Rails.application.config.assets.excluded_paths << (Gem.loaded_specs[gem_name].full_gem_path + "/app/assets/javascripts")
  Rails.application.config.assets.excluded_paths << (Gem.loaded_specs[gem_name].full_gem_path + "/app/assets/stylesheets")
end