Fixes #47909 when using order or unscope

[paulreece]

This fix corrects the logic in both the associated and missing methods. If the reflection.options hash has a key/value pair for :class_name it will use the association. This fixes 48651 which was not returning the correct value when using an enum association and querying for a record that had one key of the enum but was missing another. This also fixes 44964 where ActiveRecord was not properly aliasing self-referencing relations. If the reflection.options doesn’t contain the key/value pair then it will use the reflection.table_name. This fixes 47909 in which a user was trying to find records that were either missing a relation or were missing a relation that was ordered or unscoped or were missing a relation that was using extends in the query which resulted in an ActiveRecord Exception. It also allows for using extends in any of these capacities.

• [ X] This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• [X ] Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• [ X] Tests are added or updated if you fix a bug or add a feature.
• [X ] CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.

[zhuravel]

This breaks the following test (due to checking @scope.values[:extending]):

# frozen_string_literal: true

require "bundler/inline"

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

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  if ARGV[0] == "main"
    gem "rails", github: "rails/rails", branch: "main"
  elsif ARGV[0] == "pull_request_48861"
    gem "rails", github: "rails/rails", ref: "refs/pull/48861/head"
  else
    gem "activerecord", "7.0.6"
  end

  gem "sqlite3"
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(:books, force: true) do |t|
    t.references :progress
  end

  create_table(:progresses, force: true) do |t|
    t.references :book
    t.integer :percentage, default: 0, null: false
  end
end

module Pagination
  def page(number)
    # pagination code goes here
  end

  def per_page(number)
    # pagination code goes here
  end
end

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true

  default_scope do
    extending(Pagination) # See https://apidock.com/rails/ActiveRecord/QueryMethods/extending
  end
end

class Book < ApplicationRecord
  has_one :progress

  scope :without_progress, -> do
    where.missing(:progress)
  end

  scope :completed, -> do
    joins(:progress).merge(Progress.completed)
  end
end

class Progress < ApplicationRecord
  scope :completed, -> do
    where(percentage: 100)
  end
end

class BugTest < Minitest::Test
  def test_bug
    books = Book.order(created_at: :desc) # or `books = Book.unscope(:where)`

    assert_equal 0, books.completed.count
    assert_equal 0, books.without_progress.count
    assert_equal 0, books.without_progress.completed.count
  end
end

Run with:

ruby bug_test.rb pull_request_48861 # fails with code from this pull request
ruby bug_test.rb main # fails with code from Rails main because of https://github.com/rails/rails/pull/48738
ruby bug_test.rb # passes on ActiveRecord v7.0.6

[paulreece]

Yes I noticed that locally this morning too when I was testing other use cases. I'm in the process of building a fix into this. Thanks for bringing it to my attention!

[paulreece]

@zhuravel I built in your default_scope extend into my test app which helped narrow it down :). I think this should work for our needs now.

[rafaelfranca]

Is there any case where reflection.options[:class_name] is false but (reflection.options[:class_name] && @scope.values[:extending]) is true?

I don't get why this isn't only reflection.options[:class_name] && @scope.values[:extending]

[paulreece]

Rafael, thanks for the feedback. I had initially thought so because of an earlier iteration of this but I just ran it without the Or clause and it works! Just pushed up a version with the Or removed.

[eileencodes]

Can you remove these comments?

[paulreece]

Done! Apologies and thanks for the feedback!

[eileencodes]

Thank you!

[eileencodes]

Backported this and #48861 to 7-0-stable.