Merge pull request #360 from koic/lazy_load_cops

Load cops lazily

Author: koic

.github/workflows/test.yml

@@ -88,7 +88,7 @@ jobs:
         run: |
           sed -e "/gem 'rubocop', github: 'rubocop\/rubocop'/d" -i Gemfile
           cat << EOF > Gemfile.local
-            gem 'rubocop', '1.75.0' # Specify the oldest supported RuboCop version
+            gem 'rubocop', '1.89.0' # Specify the oldest supported RuboCop version
           EOF
       - name: set up Ruby
         uses: ruby/setup-ruby@v1

.rubocop.yml

@@ -2,6 +2,10 @@
 
 inherit_from: .rubocop_todo.yml
 
+inherit_mode:
+  merge:
+    - Exclude
+
 plugins:
   - rubocop-internal_affairs
   - rubocop-minitest
@@ -50,6 +54,10 @@ Naming/InclusiveLanguage:
       Suggestions:
         - does_not_register
 
+Style/Documentation:
+  Exclude:
+    - lib/rubocop/cop/minitest.rb
+
 Style/FormatStringToken:
   # Because we parse a lot of source codes from strings. Percent arrays
   # look like unannotated format string tokens to this cop.

Rakefile

@@ -44,7 +44,7 @@ task :new_cop, [:cop] do |_task, args|
 
   generator.write_source
   generator.write_test
-  generator.inject_require(root_file_path: 'lib/rubocop/cop/minitest_cops.rb')
+  generator.inject_registration
   generator.inject_config(config_file_path: 'config/default.yml')
 
   puts generator.todo

changelog/change_load_cops_lazily.md

@@ -0,0 +1 @@
+* [#360](https://github.com/rubocop/rubocop-minitest/pull/360): Speed up loading rubocop-minitest by lazily loading only the cops and mixins needed for a run. This requires RuboCop 1.89.0+. ([@koic][])

lib/rubocop-minitest.rb

@@ -5,4 +5,4 @@
 require_relative 'rubocop/minitest'
 require_relative 'rubocop/minitest/version'
 require_relative 'rubocop/minitest/plugin'
-require_relative 'rubocop/cop/minitest_cops'
+require_relative 'rubocop/cop/minitest'

lib/rubocop/cop/minitest.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    # Mixins are autoloaded because they're used only when the relevant cop class is loaded.
+    autoload :ArgumentRangeHelper, "#{__dir__}/mixin/argument_range_helper"
+    autoload :InDeltaMixin, "#{__dir__}/mixin/in_delta_mixin"
+    autoload :MinitestCopRule, "#{__dir__}/mixin/minitest_cop_rule"
+    autoload :MinitestExplorationHelpers, "#{__dir__}/mixin/minitest_exploration_helpers"
+
+    # Cops for the `Minitest` department. The department's cops are registered for lazy loading and their files,
+    # along with the mixins they use, are loaded on demand.
+    module Minitest
+      autoload :InstanceOfAssertionHandleable, "#{__dir__}/mixin/instance_of_assertion_handleable"
+      autoload :NilAssertionHandleable, "#{__dir__}/mixin/nil_assertion_handleable"
+      autoload :PredicateAssertionHandleable, "#{__dir__}/mixin/predicate_assertion_handleable"
+
+      extend LazyLoader
+
+      register_cop :AssertEmpty, "#{__dir__}/minitest/assert_empty"
+      register_cop :AssertEmptyLiteral, "#{__dir__}/minitest/assert_empty_literal"
+      register_cop :AssertEqual, "#{__dir__}/minitest/assert_equal"
+      register_cop :AssertInDelta, "#{__dir__}/minitest/assert_in_delta"
+      register_cop :AssertOperator, "#{__dir__}/minitest/assert_operator"
+      register_cop :AssertPredicate, "#{__dir__}/minitest/assert_predicate"
+      register_cop :AssertRaisesCompoundBody, "#{__dir__}/minitest/assert_raises_compound_body"
+      register_cop :AssertRaisesWithRegexpArgument, "#{__dir__}/minitest/assert_raises_with_regexp_argument"
+      register_cop :AssertWithExpectedArgument, "#{__dir__}/minitest/assert_with_expected_argument"
+      register_cop :AssertionInLifecycleHook, "#{__dir__}/minitest/assertion_in_lifecycle_hook"
+      register_cop :AssertKindOf, "#{__dir__}/minitest/assert_kind_of"
+      register_cop :AssertNil, "#{__dir__}/minitest/assert_nil"
+      register_cop :AssertIncludes, "#{__dir__}/minitest/assert_includes"
+      register_cop :AssertInstanceOf, "#{__dir__}/minitest/assert_instance_of"
+      register_cop :AssertMatch, "#{__dir__}/minitest/assert_match"
+      register_cop :AssertOutput, "#{__dir__}/minitest/assert_output"
+      register_cop :AssertPathExists, "#{__dir__}/minitest/assert_path_exists"
+      register_cop :AssertRespondTo, "#{__dir__}/minitest/assert_respond_to"
+      register_cop :AssertSame, "#{__dir__}/minitest/assert_same"
+      register_cop :AssertSilent, "#{__dir__}/minitest/assert_silent"
+      register_cop :AssertTruthy, "#{__dir__}/minitest/assert_truthy"
+      register_cop :DuplicateTestRun, "#{__dir__}/minitest/duplicate_test_run"
+      register_cop :EmptyLineBeforeAssertionMethods, "#{__dir__}/minitest/empty_line_before_assertion_methods"
+      register_cop :Focus, "#{__dir__}/minitest/focus"
+      register_cop :NonExecutableTestMethod, "#{__dir__}/minitest/non_executable_test_method"
+      register_cop :RedundantMessageArgument, "#{__dir__}/minitest/redundant_message_argument"
+      register_cop :ReturnInTestMethod, "#{__dir__}/minitest/return_in_test_method"
+      register_cop :TestFileName, "#{__dir__}/minitest/test_file_name"
+      register_cop :GlobalExpectations, "#{__dir__}/minitest/global_expectations"
+      register_cop :LifecycleHooksOrder, "#{__dir__}/minitest/lifecycle_hooks_order"
+      register_cop :LiteralAsActualArgument, "#{__dir__}/minitest/literal_as_actual_argument"
+      register_cop :MultipleAssertions, "#{__dir__}/minitest/multiple_assertions"
+      register_cop :NoAssertions, "#{__dir__}/minitest/no_assertions"
+      register_cop :NoTestCases, "#{__dir__}/minitest/no_test_cases"
+      register_cop :NonPublicTestMethod, "#{__dir__}/minitest/non_public_test_method"
+      register_cop :RefuteEmpty, "#{__dir__}/minitest/refute_empty"
+      register_cop :RefuteFalse, "#{__dir__}/minitest/refute_false"
+      register_cop :RefuteEqual, "#{__dir__}/minitest/refute_equal"
+      register_cop :RefuteInDelta, "#{__dir__}/minitest/refute_in_delta"
+      register_cop :RefuteIncludes, "#{__dir__}/minitest/refute_includes"
+      register_cop :RefuteInstanceOf, "#{__dir__}/minitest/refute_instance_of"
+      register_cop :RefuteKindOf, "#{__dir__}/minitest/refute_kind_of"
+      register_cop :RefuteMatch, "#{__dir__}/minitest/refute_match"
+      register_cop :RefuteNil, "#{__dir__}/minitest/refute_nil"
+      register_cop :RefuteOperator, "#{__dir__}/minitest/refute_operator"
+      register_cop :RefutePathExists, "#{__dir__}/minitest/refute_path_exists"
+      register_cop :RefutePredicate, "#{__dir__}/minitest/refute_predicate"
+      register_cop :RefuteRespondTo, "#{__dir__}/minitest/refute_respond_to"
+      register_cop :RefuteSame, "#{__dir__}/minitest/refute_same"
+      register_cop :SkipEnsure, "#{__dir__}/minitest/skip_ensure"
+      register_cop :SkipWithoutReason, "#{__dir__}/minitest/skip_without_reason"
+      register_cop :TestMethodName, "#{__dir__}/minitest/test_method_name"
+      register_cop :UnreachableAssertion, "#{__dir__}/minitest/unreachable_assertion"
+      register_cop :UnspecifiedException, "#{__dir__}/minitest/unspecified_exception"
+      register_cop :UselessAssertion, "#{__dir__}/minitest/useless_assertion"
+    end
+  end
+end

lib/rubocop/cop/minitest_cops.rb

@@ -1,64 +1,6 @@
 # frozen_string_literal: true
 
-require_relative 'mixin/argument_range_helper'
-require_relative 'mixin/in_delta_mixin'
-require_relative 'mixin/instance_of_assertion_handleable'
-require_relative 'mixin/minitest_cop_rule'
-require_relative 'mixin/minitest_exploration_helpers'
-require_relative 'mixin/nil_assertion_handleable'
-require_relative 'mixin/predicate_assertion_handleable'
-require_relative 'minitest/assert_empty'
-require_relative 'minitest/assert_empty_literal'
-require_relative 'minitest/assert_equal'
-require_relative 'minitest/assert_in_delta'
-require_relative 'minitest/assert_operator'
-require_relative 'minitest/assert_predicate'
-require_relative 'minitest/assert_raises_compound_body'
-require_relative 'minitest/assert_raises_with_regexp_argument'
-require_relative 'minitest/assert_with_expected_argument'
-require_relative 'minitest/assertion_in_lifecycle_hook'
-require_relative 'minitest/assert_kind_of'
-require_relative 'minitest/assert_nil'
-require_relative 'minitest/assert_includes'
-require_relative 'minitest/assert_instance_of'
-require_relative 'minitest/assert_match'
-require_relative 'minitest/assert_output'
-require_relative 'minitest/assert_path_exists'
-require_relative 'minitest/assert_respond_to'
-require_relative 'minitest/assert_same'
-require_relative 'minitest/assert_silent'
-require_relative 'minitest/assert_truthy'
-require_relative 'minitest/duplicate_test_run'
-require_relative 'minitest/empty_line_before_assertion_methods'
-require_relative 'minitest/focus'
-require_relative 'minitest/non_executable_test_method'
-require_relative 'minitest/redundant_message_argument'
-require_relative 'minitest/return_in_test_method'
-require_relative 'minitest/test_file_name'
-require_relative 'minitest/global_expectations'
-require_relative 'minitest/lifecycle_hooks_order'
-require_relative 'minitest/literal_as_actual_argument'
-require_relative 'minitest/multiple_assertions'
-require_relative 'minitest/no_assertions'
-require_relative 'minitest/no_test_cases'
-require_relative 'minitest/non_public_test_method'
-require_relative 'minitest/refute_empty'
-require_relative 'minitest/refute_false'
-require_relative 'minitest/refute_equal'
-require_relative 'minitest/refute_in_delta'
-require_relative 'minitest/refute_includes'
-require_relative 'minitest/refute_instance_of'
-require_relative 'minitest/refute_kind_of'
-require_relative 'minitest/refute_match'
-require_relative 'minitest/refute_nil'
-require_relative 'minitest/refute_operator'
-require_relative 'minitest/refute_path_exists'
-require_relative 'minitest/refute_predicate'
-require_relative 'minitest/refute_respond_to'
-require_relative 'minitest/refute_same'
-require_relative 'minitest/skip_ensure'
-require_relative 'minitest/skip_without_reason'
-require_relative 'minitest/test_method_name'
-require_relative 'minitest/unreachable_assertion'
-require_relative 'minitest/unspecified_exception'
-require_relative 'minitest/useless_assertion'
+# @deprecated This file is deprecated. Cops are registered for lazy loading in
+#   `rubocop/cop/minitest`; this file is kept for compatibility with code that
+#   requires it directly.
+require_relative 'minitest'

rubocop-minitest.gemspec

@@ -34,6 +34,6 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
 
   spec.add_dependency 'lint_roller', '~> 1.1'
-  spec.add_dependency 'rubocop', '>= 1.75.0', '< 2.0'
+  spec.add_dependency 'rubocop', '>= 1.89.0', '< 2.0'
   spec.add_dependency 'rubocop-ast', '>= 1.38.0', '< 2.0'
 end

test/lazy_loading_test.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require_relative 'test_helper'
+require 'tmpdir'
+
+class LazyLoadingTest < Minitest::Test
+  def test_cops_are_registered_without_loading_their_files
+    output = run_script(<<~RUBY)
+      require 'rubocop-minitest'
+
+      registry = RuboCop::Cop::Registry.global
+      loaded_cop_files = $LOADED_FEATURES.grep(%r{/rubocop/cop/minitest/})
+      loaded_mixin_files = $LOADED_FEATURES.grep(%r{\#{Regexp.escape('#{lib_dir}')}/rubocop/cop/mixin/})
+
+      puts "registered=\#{registry.names.grep(%r{\\AMinitest/}).size}"
+      puts "loaded_cop_files=\#{loaded_cop_files.size}"
+      puts "loaded_mixin_files=\#{loaded_mixin_files.size}"
+    RUBY
+
+    assert_includes(output, 'registered=55')
+    assert_includes(output, 'loaded_cop_files=0')
+    assert_includes(output, 'loaded_mixin_files=0')
+  end
+
+  def test_mixins_are_autoloaded_when_a_cop_class_is_loaded
+    output = run_script(<<~RUBY)
+      require 'rubocop-minitest'
+
+      assert_empty_cop = RuboCop::Cop::Registry.global.find_by_cop_name('Minitest/AssertEmpty')
+      assert_nil_cop = RuboCop::Cop::Registry.global.find_by_cop_name('Minitest/AssertNil')
+      loaded_mixin_files = $LOADED_FEATURES.grep(%r{\#{Regexp.escape('#{lib_dir}')}/rubocop/cop/mixin/})
+
+      puts "define_rule_applied=\#{assert_empty_cop.include?(RuboCop::Cop::ArgumentRangeHelper) &&
+        assert_empty_cop.singleton_class.include?(RuboCop::Cop::MinitestCopRule)}"
+      puts "minitest_mixin_applied=\#{assert_nil_cop.include?(RuboCop::Cop::Minitest::NilAssertionHandleable)}"
+      puts "loaded_mixin_files=\#{loaded_mixin_files.map { |path| File.basename(path) }.sort.join(',')}"
+    RUBY
+
+    assert_includes(output, 'define_rule_applied=true')
+    assert_includes(output, 'minitest_mixin_applied=true')
+    expected_mixin_files = 'argument_range_helper.rb,minitest_cop_rule.rb,nil_assertion_handleable.rb'
+    assert_includes(output, "loaded_mixin_files=#{expected_mixin_files}")
+  end
+
+  def test_a_cop_is_not_registered_twice_when_its_file_is_required_directly
+    output = run_script(<<~RUBY)
+      require 'rubocop-minitest'
+
+      before = RuboCop::Cop::Registry.global.length
+      require 'rubocop/cop/minitest/assert_empty'
+      after = RuboCop::Cop::Registry.global.length
+
+      puts "stable=\#{before == after}"
+      puts "class=\#{RuboCop::Cop::Registry.global.find_by_cop_name('Minitest/AssertEmpty')}"
+    RUBY
+
+    assert_includes(output, 'stable=true')
+    assert_includes(output, 'class=RuboCop::Cop::Minitest::AssertEmpty')
+  end
+
+  private
+
+  def run_script(source)
+    Dir.mktmpdir do |dir|
+      script = File.join(dir, 'script.rb')
+      File.write(script, source)
+      output = `#{RbConfig.ruby} -I #{lib_dir} #{script} 2>&1`
+      raise "script failed:\n#{output}" unless $CHILD_STATUS.success?
+
+      output
+    end
+  end
+
+  def lib_dir
+    File.expand_path('../lib', __dir__)
+  end
+end

test/project_test.rb

@@ -11,6 +11,17 @@ def setup
     load_feature_entries
   end
 
+  def test_every_cop_file_is_registered_exactly_once
+    cop_root = File.expand_path('../lib/rubocop/cop', __dir__)
+    files = Dir[File.join(cop_root, 'minitest', '*.rb')].sort
+
+    registered = RuboCop::Cop::Registry.global.cops_for_department(:Minitest).map do |cop|
+      Object.const_source_location(cop.name).first
+    end.sort
+
+    assert_equal(files, registered)
+  end
+
   def test_changelog_has_newline_at_end_of_file
     assert(@changelog.end_with?("\n"))
   end