Initialize ViewComponent::Config with defaults before framework load

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 5
 
 ## main
 
+* Initialize ViewComponent::Config with defaults before framework load.
+
+    *Simon Fish*
+
 * Add 3.2 to the list of Ruby CI versions
 
     *Igor Drozdov*

lib/view_component/base.rb

@@ -22,12 +22,8 @@ class << self
       #
       # @return [ActiveSupport::OrderedOptions]
       def config
-        @config ||= ActiveSupport::OrderedOptions.new
+        ViewComponent::Config.current
       end
-
-      # Replaces the entire config. You shouldn't need to use this directly
-      # unless you're building a `ViewComponent::Config` elsewhere.
-      attr_writer :config
     end
 
     include ViewComponent::InlineTemplate

lib/view_component/config.rb

@@ -167,6 +167,14 @@ def default_generate_options
       end
     end
 
+    # @!attribute current
+    # @return [ViewComponent::Config]
+    # Returns the current ViewComponent::Config. This is persisted against this
+    # class so that config options remain accessible before the rest of
+    # ViewComponent has loaded. Defaults to an instance of ViewComponent::Config
+    # with all other documented defaults set.
+    class_attribute :current, default: defaults, instance_predicate: false
+
     def initialize
       @config = self.class.defaults
     end

lib/view_component/engine.rb

@@ -6,7 +6,7 @@
 
 module ViewComponent
   class Engine < Rails::Engine # :nodoc:
-    config.view_component = ViewComponent::Config.defaults
+    config.view_component = ViewComponent::Config.current
 
     rake_tasks do
       load "view_component/rails/tasks/view_component.rake"
@@ -15,6 +15,9 @@ class Engine < Rails::Engine # :nodoc:
     initializer "view_component.set_configs" do |app|
       options = app.config.view_component
 
+      %i[generate preview_controller preview_route show_previews_source].each do |config_option|
+        options[config_option] ||= ViewComponent::Base.public_send(config_option)
+      end
       options.instrumentation_enabled = false if options.instrumentation_enabled.nil?
       options.render_monkey_patch_enabled = true if options.render_monkey_patch_enabled.nil?
       options.show_previews = (Rails.env.development? || Rails.env.test?) if options.show_previews.nil?
@@ -37,8 +40,6 @@ class Engine < Rails::Engine # :nodoc:
 
     initializer "view_component.enable_instrumentation" do |app|
       ActiveSupport.on_load(:view_component) do
-        Base.config = app.config.view_component
-
         if app.config.view_component.instrumentation_enabled.present?
           # :nocov: Re-executing the below in tests duplicates initializers and causes order-dependent failures.
           ViewComponent::Base.prepend(ViewComponent::Instrumentation)

lib/view_component/preview.rb

@@ -4,7 +4,7 @@
 
 module ViewComponent # :nodoc:
   class Preview
-    include Rails.application.routes.url_helpers if defined?(Rails.application.routes.url_helpers)
+    include Rails.application.routes.url_helpers if defined?(Rails) && Rails.application.present?
     include ActionView::Helpers::TagHelper
     include ActionView::Helpers::AssetTagHelper
     extend ActiveSupport::DescendantsTracker

test/sandbox/test/config_test.rb

@@ -34,7 +34,7 @@ def test_all_methods_are_documented
       end
       options_defined_on_instance = Set[*default_options, *accessors]
       assert options_defined_on_instance.subset?(Set[*configuration_methods_to_document.map(&:name)]),
-        "Not all configuration options are documented: #{configuration_methods_to_document.map(&:name) - options_defined_on_instance.to_a}"
+        "Not all configuration options are documented: #{options_defined_on_instance.to_a - configuration_methods_to_document.map(&:name)}"
       assert configuration_methods_to_document.map(&:docstring).all?(&:present?),
         "Configuration options are missing docstrings."
     end