DEV: debundle plugin css assets and don't load if disabled (#7646)

lib/stylesheet/compiler.rb

@@ -12,7 +12,7 @@ module Stylesheet
 
       if Importer.special_imports[asset.to_s]
         filename = "theme_#{options[:theme_id]}.scss"
-        file = "@import \"common/foundation/variables\"; @import \"theme_variables\"; @import \"#{asset}\";"
+        file = "@import \"common/foundation/variables\"; @import \"common/foundation/mixins\"; @import \"theme_variables\"; @import \"#{asset}\";"
       else
         filename = "#{asset}.scss"
         path = "#{ASSET_ROOT}/#{filename}"

lib/stylesheet/importer.rb

@@ -19,16 +19,19 @@ module Stylesheet
       Import.new("#{theme_dir(@theme_id)}/theme_field.scss", source: @theme_field)
     end
 
-    register_import "plugins" do
-      import_files(DiscoursePluginRegistry.stylesheets)
-    end
+    Discourse.plugins.each do |plugin|
+      plugin_directory_name = plugin.directory_name
 
-    register_import "plugins_mobile" do
-      import_files(DiscoursePluginRegistry.mobile_stylesheets)
-    end
+      ["", "mobile", "desktop"].each do |type|
+        asset_name = type.present? ? "#{plugin_directory_name}_#{type}" : plugin_directory_name
+        stylesheets = type.present? ? DiscoursePluginRegistry.send("#{type}_stylesheets") : DiscoursePluginRegistry.stylesheets
 
-    register_import "plugins_desktop" do
-      import_files(DiscoursePluginRegistry.desktop_stylesheets)
+        if stylesheets[plugin_directory_name].present?
+          register_import asset_name do
+            import_files(stylesheets[plugin_directory_name])
+          end
+        end
+      end
     end
 
     register_import "plugins_variables" do

lib/stylesheet/manager.rb

@@ -294,9 +294,9 @@ class Stylesheet::Manager
   # so we could end up poisoning the cache with a bad file that can not be removed
   def plugins_digest
     assets = []
-    assets += DiscoursePluginRegistry.stylesheets.to_a
-    assets += DiscoursePluginRegistry.mobile_stylesheets.to_a
-    assets += DiscoursePluginRegistry.desktop_stylesheets.to_a
+    DiscoursePluginRegistry.stylesheets.each { |_, paths| assets += paths.to_a }
+    DiscoursePluginRegistry.mobile_stylesheets.each { |_, paths| assets += paths.to_a }
+    DiscoursePluginRegistry.desktop_stylesheets.each { |_, paths| assets += paths.to_a }
     Digest::SHA1.hexdigest(assets.sort.join)
   end