从MongoDB升级到PostgreSQL，求Spork.trap_class_method对应替代方案

Hey there! I get it—switching ORMs can throw up some confusing little roadblocks, especially with test setup tools like Spork. Let's get this sorted out.

The Problem Breakdown #

Your original line Spork.trap_class_method(Rails::Mongoid, :load_models) was telling Spork to intercept Mongoid's model loading process, which keeps your tests fast by avoiding reloading models every time you run a test suite. Since you're moving to PostgreSQL, you're now using ActiveRecord instead of Mongoid, so that Mongoid-specific method won't work anymore.

The ActiveRecord Alternative #

Replace that Mongoid line with code that targets ActiveRecord's schema and model loading lifecycle. Here's what to put in your spec_helper.rb inside the Spork.prefork block:

Spork.prefork do
  # ... keep your existing config like RSpec setup, FactoryBot, etc. ...

  # Replace the Mongoid load_models trap with this ActiveRecord equivalent
  Spork.trap_class_method(ActiveRecord::Base, :load_schema)

  # Optional: Clear reloadable connections to avoid database connection issues between forks
  ActiveRecord::Base.clear_reloadable_connections!
end

# And in the each_run block (runs before every test run), add this to refresh model state:
Spork.each_run do
  ActiveRecord::Base.reset_column_information
  # If you use FactoryBot, you might also want to add: FactoryBot.reload
end

Why This Works #

• Spork.trap_class_method(ActiveRecord::Base, :load_schema) does the same job as the Mongoid line, but for ActiveRecord: it tells Spork to cache the schema loading process during the pre-fork phase, so it doesn't redo that work for every test.
• ActiveRecord::Base.clear_reloadable_connections! prevents connection leaks between Spork's forked processes, which is a common issue when using ActiveRecord with Spork.
• ActiveRecord::Base.reset_column_information ensures that any changes to your database schema (like migrations run between test runs) are reflected in your models.

Quick Notes for Different Rails Versions #

• If you're on Rails 5 or newer, Spork usage has declined a bit (many folks use Spring instead), but if you're sticking with Spork, this code should still work.
• If you run into issues with eager loading, you can add Rails.application.config.eager_load = false inside the prefork block to prevent Rails from eager loading models before Spork forks.

内容的提问来源于stack exchange，提问作者MEENAKSHI KUMARI