Fix follow up tasks for assets:precompile when no manifest existed

When no `.sprockets-manifest-xxx.json` existed, every instance of
`Sprockets::Manifest` generated their own path with their own random
filename, and since this happened before the assets were actually
precompiled, they were all empty. So the error pages didn't find the
manifest and the non-digest assets also didn't have any assets to copy.

So lets create our own instance of `Sprockets::Manifest` here, AFTER
`assets:precompile`, which then loads the manifest json that was used
during precompile, so all precompiled assets are available.

closes #8366

Changelog.md

@@ -6,7 +6,11 @@
 * Fix deprecation warnings for sidekiq 7.0 [#8359](https://github.com/diaspora/diaspora/pull/8359)
 * Remove entypo-rails dependency to prepare for rails 6 [#8361](https://github.com/diaspora/diaspora/pull/8361)
 * Remove compass-rails dependency which is not supported anymore [#8362](https://github.com/diaspora/diaspora/pull/8362)
+* Switch to sassc-rails which speeds up `assets:precompile` a lot [#8362](https://github.com/diaspora/diaspora/pull/8362)
 * Remove markerb dependency which doesn't exist anymore [#8365](https://github.com/diaspora/diaspora/pull/8365)
+* Upgrade to rails 6.1 [#8366](https://github.com/diaspora/diaspora/pull/8366)
+* Update the suggested Ruby version to 2.7. If you run into trouble during the update and you followed our installation guides, run `rvm install 2.7`. [#8366](https://github.com/diaspora/diaspora/pull/8366)
+* Upgrade to bundler 2 [#8366](https://github.com/diaspora/diaspora/pull/8366)
 
 ## Bug fixes
 * Fix that no mails were sent after photo export [#8365](https://github.com/diaspora/diaspora/pull/8365)

lib/tasks/assets.rake

@@ -1,35 +1,40 @@
 # frozen_string_literal: true
 
 namespace :assets do
+  # create new assets manifest for tasks which run after assets:precompile
+  def assets_manifest
+    return @assets_manifest if @assets_manifest
+
+    config = Diaspora::Application.config
+    path = File.join(config.paths["public"].first, config.assets.prefix)
+    @assets_manifest = Sprockets::Manifest.new(Diaspora::Application.assets, path, config.assets.manifest)
+  end
+
   desc "Generate error pages"
-  task :generate_error_pages => :environment do
+  task generate_error_pages: :environment do
+    ApplicationController.view_context_class.assets_manifest = assets_manifest
     renderer = ErrorPageRenderer.new codes: [404, 422, 500]
     renderer.render
   end
 
   desc "Create non digest assets"
   task non_digest_assets: :environment do
-    logger = ::Logging::Logger["assets:non_digest_assets"]
+    Diaspora::Application.config.assets.non_digest_assets.each do |asset|
+      digested_path = assets_manifest.assets[asset]
+      raise Sprockets::Rails::Helper::AssetNotFound, "Precompiled asset for '#{asset}' not found" unless digested_path
 
-    non_digest_assets = Diaspora::Application.config.assets.non_digest_assets
+      full_digested_path     = File.join(assets_manifest.directory, digested_path)
-
+      full_non_digested_path = File.join(assets_manifest.directory, asset)
-    Rails.application.assets_manifest.assets.each do |logical_path, digested_path|
-      logical_pathname = Pathname.new(logical_path)
-      next unless non_digest_assets.any? {|testpath| logical_pathname.fnmatch?(testpath, File::FNM_PATHNAME) }
-
-      full_digested_path     = Rails.root.join("public", "assets", digested_path)
-      full_non_digested_path = Rails.root.join("public", "assets", logical_path)
 
       next unless FileUtils.uptodate?(full_digested_path, [full_non_digested_path])
 
-      logger.info "Copying #{full_digested_path} to #{full_non_digested_path}"
+      puts "Copying #{full_digested_path} to #{full_non_digested_path}"
-
       FileUtils.copy_file(full_digested_path, full_non_digested_path, true)
     end
   end
 
   # Augment precompile with error page generation
-  task :precompile do
+  Rake::Task[:precompile].enhance do
     Rake::Task["assets:generate_error_pages"].invoke
     Rake::Task["assets:non_digest_assets"].invoke
   end