Add rubocop rule for enable_lock_retries

This change adds a rubocop rule to prevent using disable_ddl_transaction
and enable_lock_retries together.

rubocop/cop/migration/prevent_global_enable_lock_retries_with_disable_ddl_transaction.rb

+# frozen_string_literal: true
+
+require_relative '../../migration_helpers'
+
+module RuboCop
+  module Cop
+    module Migration
+      # Cop that prevents usage of `enable_lock_retries!` within the `disable_ddl_transaction!` method.
+      class PreventGlobalEnableLockRetriesWithDisableDdlTransaction < RuboCop::Cop::Cop
+        include MigrationHelpers
+
+        MSG = '`enable_lock_retries!` cannot be used with `disable_ddl_transaction!`. Use the `with_lock_retries` helper method to define retriable code blocks.'
+
+        def_node_matcher :enable_lock_retries?, <<~PATTERN
+          (send _ :enable_lock_retries! ...)
+        PATTERN
+
+        def_node_matcher :disable_ddl_transaction?, <<~PATTERN
+          (send _ :disable_ddl_transaction! ...)
+        PATTERN
+
+        def on_begin(node)
+          return unless in_migration?(node)
+
+          has_enable_lock_retries = false
+          has_disable_ddl_transaction = false
+
+          node.each_descendant(:send) do |send_node|
+            has_enable_lock_retries = true if enable_lock_retries?(send_node)
+            has_disable_ddl_transaction = true if disable_ddl_transaction?(send_node)
+
+            if has_enable_lock_retries && has_disable_ddl_transaction
+              add_offense(send_node, message: MSG)
+              break
+            end
+          end
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/migration/prevent_global_enable_lock_retries_with_disable_ddl_transaction_spec.rb

+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+require_relative '../../../../rubocop/cop/migration/prevent_global_enable_lock_retries_with_disable_ddl_transaction'
+
+RSpec.describe RuboCop::Cop::Migration::PreventGlobalEnableLockRetriesWithDisableDdlTransaction do
+  subject(:cop) { described_class.new }
+
+  context 'when in migration' do
+    before do
+      allow(cop).to receive(:in_migration?).and_return(true)
+    end
+
+    it 'registers an offense when `enable_lock_retries` and `disable_ddl_transaction` is used together' do
+      code = <<~RUBY
+      class SomeMigration < ActiveRecord::Migration[6.0]
+        enable_lock_retries!
+        disable_ddl_transaction!
+      end
+      RUBY
+
+      expect_offense(<<~RUBY, node: code, msg: described_class::MSG)
+        class SomeMigration < ActiveRecord::Migration[6.0]
+          enable_lock_retries!
+          disable_ddl_transaction!
+          ^^^^^^^^^^^^^^^^^^^^^^^^ %{msg}
+        end
+      RUBY
+    end
+
+    it 'registers no offense when `enable_lock_retries!` is used' do
+      expect_no_offenses(<<~RUBY)
+        class SomeMigration < ActiveRecord::Migration[6.0]
+          enable_lock_retries!
+        end
+      RUBY
+    end
+
+    it 'registers no offense when `disable_ddl_transaction!` is used' do
+      expect_no_offenses(<<~RUBY)
+        class SomeMigration < ActiveRecord::Migration[6.0]
+          disable_ddl_transaction!
+        end
+      RUBY
+    end
+  end
+
+  context 'when outside of migration' do
+    it 'registers no offense' do
+      expect_no_offenses(<<~RUBY)
+        class SomeMigration
+          enable_lock_retries!
+          disable_ddl_transaction!
+        end
+      RUBY
+    end
+  end
+end