Add cop Rake/Require

This cop flags use of global `require` in rake files.

Load dependencies lazily in `task` definitions instead.

.rubocop.yml

@@ -844,3 +844,8 @@ Cop/SidekiqApiUsage:
     - 'lib/gitlab/sidekiq_queue.rb'
     - 'config/initializers/sidekiq.rb'
     - 'config/initializers/forbid_sidekiq_in_transactions.rb'
+
+Rake/Require:
+  Include:
+    - '{,ee/,jh/}lib/**/*.rake'
+    - 'qa/tasks/**/*.rake'

.rubocop_todo/rake/require.yml

+---
+Rake/Require:
+  Details: grace period
+  Exclude:
+    - 'ee/lib/tasks/gitlab/spdx.rake'
+    - 'lib/tasks/gitlab/artifacts/migrate.rake'
+    - 'lib/tasks/gitlab/assets.rake'
+    - 'lib/tasks/gitlab/backup.rake'
+    - 'lib/tasks/gitlab/cleanup.rake'
+    - 'lib/tasks/gitlab/dependency_proxy/migrate.rake'
+    - 'lib/tasks/gitlab/docs/redirect.rake'
+    - 'lib/tasks/gitlab/graphql.rake'
+    - 'lib/tasks/gitlab/lfs/migrate.rake'
+    - 'lib/tasks/gitlab/metrics_exporter.rake'
+    - 'lib/tasks/gitlab/openapi.rake'
+    - 'lib/tasks/gitlab/packages/events.rake'
+    - 'lib/tasks/gitlab/packages/migrate.rake'
+    - 'lib/tasks/gitlab/pages.rake'
+    - 'lib/tasks/gitlab/refresh_project_statistics_build_artifacts_size.rake'
+    - 'lib/tasks/gitlab/terraform/migrate.rake'
+    - 'lib/tasks/gitlab/tw/codeowners.rake'
+    - 'lib/tasks/gitlab/x509/update.rake'
+    - 'lib/tasks/import.rake'
+    - 'lib/tasks/tokens.rake'
+    - 'qa/tasks/ci.rake'
+    - 'qa/tasks/webdrivers.rake'

rubocop/cop/rake/require.rb

+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Rake
+      # Flag global `require`s or `require_relative`s in rake files.
+      #
+      # Load dependencies lazily in `task` definitions if possible.
+      #
+      # @example
+      #   # bad
+      #
+      #   require_relative 'gitlab/json'
+      #   require 'json'
+      #
+      #   task :parse_json do
+      #     Gitlab::Json.parse(...)
+      #   end
+      #
+      #   # good
+      #
+      #   task :parse_json do
+      #     require_relative 'gitlab/json'
+      #     require 'json'
+      #
+      #     Gitlab::Json.parse(...)
+      #   end
+      #
+      #   RSpec::Core::RakeTask.new(:parse_json) do |t, args|
+      #     require_relative 'gitlab/json'
+      #     require 'json'
+      #
+      #     Gitlab::Json.parse(...)
+      #   end
+      #
+      #   # Requiring files which contain the word `task` is allowed.
+      #   require 'some_gem/rake_task'
+      #   require 'some_gem/rake_tasks'
+      #
+      #   SomeGem.define_tasks
+      #
+      #   # Loading in method definition as well.
+      #   def load_deps
+      #     require 'json'
+      #   end
+      #
+      #   task :parse_json
+      #     load_deps
+      #   end
+      #
+      class Require < RuboCop::Cop::Base
+        MSG = 'Load dependencies inside `task` definitions if possible.'
+
+        METHODS = %i[require require_relative].freeze
+        RESTRICT_ON_SEND = METHODS
+
+        def_node_matcher :require_method, <<~PATTERN
+          (send nil? ${#{METHODS.map(&:inspect).join(' ')}} $_)
+        PATTERN
+
+        def on_send(node)
+          method, file = require_method(node)
+          return unless method
+
+          return if requires_task?(file)
+          return if inside_block_or_method?(node)
+
+          add_offense(node)
+        end
+
+        private
+
+        # Allow `require "foo/rake_task"`
+        def requires_task?(file)
+          file.source.include?('task')
+        end
+
+        def inside_block_or_method?(node)
+          node.each_ancestor(:block, :def).any?
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/rake/require_spec.rb

+# frozen_string_literal: true
+
+require 'rubocop_spec_helper'
+
+require_relative '../../../../rubocop/cop/rake/require'
+
+RSpec.describe RuboCop::Cop::Rake::Require do
+  let(:msg) { described_class::MSG }
+
+  it 'registers an offenses for require methods' do
+    expect_offense(<<~RUBY)
+      require 'json'
+      ^^^^^^^^^^^^^^ #{msg}
+      require_relative 'gitlab/json'
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{msg}
+    RUBY
+  end
+
+  it 'does not register offense inside `task` definition' do
+    expect_no_offenses(<<~RUBY)
+      task :parse do
+        require 'json'
+      end
+
+      namespace :some do
+        task parse: :env do
+          require_relative 'gitlab/json'
+        end
+      end
+    RUBY
+  end
+
+  it 'does not register offense inside a block definition' do
+    expect_no_offenses(<<~RUBY)
+      RSpec::Core::RakeTask.new(:parse_json) do |t, args|
+        require 'json'
+      end
+    RUBY
+  end
+
+  it 'does not register offense inside a method definition' do
+    expect_no_offenses(<<~RUBY)
+      def load_deps
+        require 'json'
+      end
+
+      task :parse do
+        load_deps
+      end
+    RUBY
+  end
+
+  it 'does not register offense when require task related files' do
+    expect_no_offenses(<<~RUBY)
+      require 'rubocop/rake_tasks'
+      require 'gettext_i18n_rails/tasks'
+      require_relative '../../rubocop/check_graceful_task'
+    RUBY
+  end
+end