Add an in-project linter rule and rule test support

.github/workflows/ci.yml

@@ -67,6 +67,10 @@ jobs:
       - name: Run Ruby tests
         run: bundle exec rake test
 
+      - name: Run Rubydex linter
+        if: matrix.os == 'ubuntu-latest' && matrix.ruby == '4.0'
+        run: bundle exec rdx lint .
+
       - name: Save Rust compile cache
         id: rust-compile-cache-save
         uses: actions/cache/save@v6

lib/rubydex/cli/command/lint.rb

@@ -29,7 +29,10 @@ def run
           warn_unknown_rules(config.linter, rules)
 
           graph = build_graph($stderr, workspace_path:, config:, fail_on_index_errors: true)
-          result = Rubydex::Linter::Runner.new(graph, rules:, config: config.linter).run
+          runner = Rubydex::Linter::Runner.new(graph, rules:, config: config.linter)
+          rule_count = runner.rules.size
+          $stderr.puts("Running #{rule_count} #{pluralize("rule", rule_count)}...")
+          result = runner.run
           if result.diagnostics.empty?
             print_summary(graph.documents.count, result.diagnostics)
             return

lib/rubydex/graph.rb

@@ -62,7 +62,8 @@ def add_workspace_dependency_paths(paths)
           # descending them
           next if File.absolute_path?(path)
 
-          paths << File.join(spec.full_gem_path, path)
+          require_path = File.join(spec.full_gem_path, path)
+          paths << require_path if File.directory?(require_path)
         end
       rescue Gem::MissingSpecError
         nil

lib/rubydex/linter/rule_loader.rb

@@ -5,25 +5,26 @@ module Linter
     # Loads project and bundled-gem rules using the Rubydex linter path convention.
     class RuleLoader
       RULE_GLOB = "rubydex_linter/rules/**/*.rb" #: String
+      BUILT_IN_RULE_GLOB = File.expand_path("../../rubydex_linter/rules/**/*.rb", __dir__) #: String
 
       class << self
         #: (String workspace_path) -> Array[singleton(Rule)]
         def load(workspace_path)
           existing_rules = Rule.subclasses
-          rule_files = Dir.glob(RULE_GLOB, base: workspace_path).map do |rule_file|
+          rule_files = Dir.glob(BUILT_IN_RULE_GLOB)
+          rule_files.concat(Dir.glob(RULE_GLOB, base: workspace_path).map do |rule_file|
             File.expand_path(rule_file, workspace_path)
-          end
-          if ENV["BUNDLE_GEMFILE"]
-            rule_files.concat(Gem.find_latest_files(RULE_GLOB))
-          end
+          end)
+          rule_files.concat(Gem.find_latest_files(RULE_GLOB)) if ENV["BUNDLE_GEMFILE"]
 
           rule_files.each do |rule_file|
             require rule_file
           rescue LoadError, SyntaxError => error
             raise RuleLoadError, "Unable to load linter rules from #{rule_file}: #{error.message}", cause: error
           end
 
-          Rule.subclasses - existing_rules
+          built_in_rules = [Rules::RuleStructure] #: Array[singleton(Rule)]
+          built_in_rules | (Rule.subclasses - existing_rules)
         end
       end
     end