DEV: Remove child theme settings/variables from parent compilation (#16001)

aa1442fdc3 split theme stylesheets so that every component gets its own stylesheet. Therefore, there is now no need for parent themes to collate the settings/variables of its children during scss compilation.

Technically this is a breaking change for any themes which depend on the settings/variables of their child components. That was never a supported/recommended arrangement, so we don't expect this to cause issues.

app/models/theme.rb

@@ -470,16 +470,6 @@ class Theme < ActiveRecord::Base
     end
   end
 
-  def all_theme_variables
-    fields = {}
-    ids = Theme.transform_ids(id)
-    ThemeField.find_by_theme_ids(ids).where(type_id: ThemeField.theme_var_type_ids).each do |field|
-      next if fields.key?(field.name)
-      fields[field.name] = field
-    end
-    fields.values
-  end
-
   def add_relative_theme!(kind, theme)
     new_relation = if kind == :child
       child_theme_relation.new(child_theme_id: theme.id)
@@ -559,17 +549,6 @@ class Theme < ActiveRecord::Base
     hash
   end
 
-  def included_settings
-    hash = {}
-
-    Theme.where(id: Theme.transform_ids(id)).each do |theme|
-      hash.merge!(theme.build_settings_hash)
-    end
-
-    hash.merge!(self.build_settings_hash)
-    hash
-  end
-
   def update_setting(setting_name, new_value)
     target_setting = settings.find { |setting| setting.name == setting_name }
     raise Discourse::NotFound unless target_setting
@@ -654,11 +633,14 @@ class Theme < ActiveRecord::Base
   end
 
   def scss_variables
-    return if all_theme_variables.empty? && included_settings.empty?
+    settings_hash = build_settings_hash
+    theme_variable_fields = var_theme_fields
+
+    return if theme_variable_fields.empty? && settings_hash.empty?
 
     contents = +""
 
-    all_theme_variables&.each do |field|
+    theme_variable_fields&.each do |field|
       if field.type_id == ThemeField.types[:theme_upload_var]
         if upload = field.upload
           url = upload_cdn_path(upload.url)
@@ -669,7 +651,7 @@ class Theme < ActiveRecord::Base
       end
     end
 
-    included_settings&.each do |name, value|
+    settings_hash&.each do |name, value|
       next if name == "theme_uploads"
       contents << to_scss_variable(name, value)
     end

spec/models/theme_spec.rb

@@ -565,36 +565,6 @@ HTML
     expect(json["my_upload"]).to eq("http://cdn.localhost#{upload.url}")
   end
 
-  it 'handles child settings correctly' do
-    Theme.destroy_all
-
-    expect(included_settings(theme.id)).to eq("{}")
-
-    theme.set_field(target: :settings, name: "yaml", value: "boolean_setting: true")
-    theme.save!
-    expect(included_settings(theme.id)).to match(/\"boolean_setting\":true/)
-
-    theme.settings.first.value = "false"
-    theme.save!
-    expect(included_settings(theme.id)).to match(/\"boolean_setting\":false/)
-
-    child.set_field(target: :settings, name: "yaml", value: "integer_setting: 54")
-
-    child.save!
-    theme.add_relative_theme!(:child, child)
-
-    json = included_settings(theme.id)
-    expect(json).to match(/\"boolean_setting\":false/)
-    expect(json).to match(/\"integer_setting\":54/)
-
-    expect(included_settings(child.id)).to eq("{\"integer_setting\":54}")
-
-    child.destroy!
-    json = included_settings(theme.id)
-    expect(json).not_to match(/\"integer_setting\":54/)
-    expect(json).to match(/\"boolean_setting\":false/)
-  end
-
   describe "convert_settings" do
 
     it 'can migrate a list field to a string field with json schema' do

spec/requests/admin/themes_controller_spec.rb

@@ -650,7 +650,7 @@ describe Admin::ThemesController do
       expect(response.parsed_body["bg"]).to eq("green")
 
       theme.reload
-      expect(theme.included_settings[:bg]).to eq("green")
+      expect(theme.cached_settings[:bg]).to eq("green")
       user_history = UserHistory.last
 
       expect(user_history.action).to eq(
@@ -663,7 +663,7 @@ describe Admin::ThemesController do
       theme.reload
 
       expect(response.status).to eq(200)
-      expect(theme.included_settings[:bg]).to eq("")
+      expect(theme.cached_settings[:bg]).to eq("")
     end
   end
 end