permanent_connection_checkout.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  gem "rails", git: "https://github.com/rails/rails.git"
  # If you want to test against edge Rails replace the previous line with this:
  # gem "rails", github: "rails/rails", branch: "main"

  gem "sqlite3", "~> 1.4"
end

require "active_record"
require "minitest/autorun"
require "logger"

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord.permanent_connection_checkout = :disallowed

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_bare_connection
    assert_raises(ActiveRecord::ActiveRecordError) do
      post = Post.create!
      post.comments << Comment.create!
    end
  end
end

with_connection.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  gem "rails", git: "https://github.com/rails/rails.git"
  # If you want to test against edge Rails replace the previous line with this:
  # gem "rails", github: "rails/rails", branch: "main"

  gem "sqlite3", "~> 1.4"
end

require "active_record"
require "minitest/autorun"
require "logger"

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_with_connection
    Post.with_connection do
      post = Post.create!
      post.comments << Comment.create!

      assert_equal 1, post.comments.count
      assert_equal 1, Comment.count
      assert_equal post.id, Comment.first.post.id
    end

    assert_equal 0, Post.connection_pool.stat[:busy]
  end

  def test_with_connection_prevent_permanent_checkout
    Post.with_connection(prevent_permanent_checkout: true) do
      post = Post.create!
      post.comments << Comment.create!

      assert_equal 1, post.comments.count
      assert_equal 1, Comment.count
      assert_equal post.id, Comment.first.post.id
    end

    assert_equal 0, Post.connection_pool.stat[:busy]
  end
end