Support template dependency tracking in Rails 4

[jlecour]

Hi,

I've noticed that nested partials were not used in the dependency tracking for Rails 4 caching.

With cache enabled, Rails is hashing each template to detect changes and change the cache key. It is also configured to look inside ERB templates and partials for inclusion of other templates of partials. The problem is that Rails is only looking inside *.erb files. When using Slim, only the top template is analyzed.

In the [indirect/haml-rails](https://github.com/indirect/haml-rails/] project, there is a railtie that registers the tracker for *.haml templates.

I guess Slim should do something similar.

I've added a basic initializer in my app and it works :

if defined?(CacheDigests::DependencyTracker)
  # 'cache_digests' gem being used (overrides Rails 4 implementation)
  CacheDigests::DependencyTracker.register_tracker :slim, CacheDigests::DependencyTracker::ERBTracker

  if ::Rails.env.development?
    # recalculate cache digest keys for each request
    CacheDigests::TemplateDigestor.cache = ActiveSupport::Cache::NullStore.new
  end
else
  # will only apply if Rails 4, which includes 'action_view/dependency_tracker'
  require 'action_view/dependency_tracker'
  ActionView::DependencyTracker.register_tracker :slim, ActionView::DependencyTracker::ERBTracker
end

[minad]

Should this be part of slim-rails or slim?

[jlecour]

@minad Since Slim claims that slim-rails is not needed to use it with Rails (just for generators) I guess it should be part of slim.

That said, I think that everything related to frameworks integration should be in a separate gem, with only the templating parts in slim.

[clemensg]

@minad Maybe slim-rails is the best choice, because this is an optional enhancement. You can use slim with Rails without slim-rails, but if you do use slim-rails, you get dependency tracking in the template cache.

I would really like slim to take advantage of dependency tracking.

[minad]

moved issue to slim-rails