Improve form path detection

app/lib/primer/forms/acts_as_component.rb

@@ -50,8 +50,6 @@ def self.extended(base)
       TemplateGlob = Struct.new(:glob_pattern, :method_name, :on_compile_callback)
       TemplateParams = Struct.new(:source, :identifier, :type, :format, keyword_init: true)
 
-      attr_accessor :template_root_path
-
       def renders_templates(glob_pattern, method_name = nil, &block)
         template_globs << TemplateGlob.new(glob_pattern, method_name, block)
       end
@@ -70,6 +68,15 @@ def compile!
 
       private
 
+      def template_root_path
+        return @template_root_path if defined?(@template_root_path)
+
+        form_path = Utils.const_source_location(self.name)
+        @template_root_path = if form_path
+          File.join(File.dirname(form_path), self.name.demodulize.underscore)
+        end
+      end
+
       def template_globs
         @template_globs ||= []
       end

app/lib/primer/forms/base.rb

@@ -29,11 +29,6 @@ def new(builder, **options)
         end
 
         def inherited(base)
-          form_path = Utils.const_source_location(base.name)
-          return unless form_path
-
-          base.template_root_path = File.join(File.dirname(form_path), base.name.demodulize.underscore)
-
           base.renders_template "after_content.html.erb" do
             base.instance_variable_set(:@has_after_content, true)
           end

app/lib/primer/forms/base_component.rb

@@ -7,16 +7,18 @@ class BaseComponent
       include Primer::ClassNameHelper
       extend ActsAsComponent
 
-      def self.inherited(base)
-        base_path = Utils.const_source_location(base.name)
+      def self.compile!
+        base_path = Utils.const_source_location(self.name)
 
         unless base_path
           warn "Could not identify the template for #{base}"
           return
         end
 
         dir = File.dirname(base_path)
-        base.renders_template File.join(dir, "#{base.name.demodulize.underscore}.html.erb"), :render_template
+        renders_template File.join(dir, "#{self.name.demodulize.underscore}.html.erb"), :render_template
+
+        super
       end
 
       delegate :required?, :disabled?, :hidden?, to: :@input

app/lib/primer/forms/utils.rb

@@ -17,10 +17,20 @@ module Utils
       def const_source_location(class_name)
         return nil unless class_name
 
+        if (location = Object.const_source_location(class_name)&.[](0))
+          return location
+        end
+
         # NOTE: underscore respects namespacing, i.e. will convert Foo::Bar to foo/bar.
         class_path = "#{class_name.underscore}.rb"
 
-        ActiveSupport::Dependencies.autoload_paths.each do |autoload_path|
+        autoload_paths = if Rails.respond_to?(:autoloaders) && Rails.autoloaders.zeitwerk_enabled?
+          Rails.autoloaders.main.dirs
+        else
+          ActiveSupport::Dependencies.autoload_paths
+        end
+
+        Rails.autoloaders.main.dirs.each do |autoload_path|
           absolute_path = File.join(autoload_path, class_path)
           return absolute_path if File.exist?(absolute_path)
         end