Initialize ViewComponent::Config with defaults before framework load

This commit introduces `ViewComponent::Config.current`, which should not be used directly by consumers of ViewComponent, but is used as the common thread from which `ViewComponent::Base` and `Rails.application.config.view_component` will load their config once each is ready. It'll make config available from the very start with the intent of not relying upon the framework to find these options - we can manually set anything reliant on Action View, for example, within app/engine config.

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 5
 
 ## main
 
+* Initialize ViewComponent::Config with defaults before framework load.
+
+    *Simon Fish*
+
 * Add Skroutz to users list.
 
     *Chris Nitsas*

lib/view_component/base.rb

@@ -22,12 +22,14 @@ class << self
       #
       # @return [ActiveSupport::OrderedOptions]
       def config
-        @config ||= ViewComponent::Config.defaults
+        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
+      def config=(*args)
+        ViewComponent::Config.current = *args
+      end
     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::Base.config
+    config.view_component = ViewComponent::Config.current
 
     rake_tasks do
       load "view_component/rails/tasks/view_component.rake"

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