Fix find_or_create_by! not checking owner persistence:

- Fix rails#54920
- ### Problem

  In rails#54845, I modified a call to `Record#create` for
  `Record#new` followed by `Record#save`. I didn't seen that the
  behaviour between both is different on associations.

  https://github.com/rails/rails/blob/b97917da8a801bf5360c3a9da913415bc8582735/activerecord/lib/active_record/associations/collection_association.rb#L355-L356

  ```ruby
  car = Car.new
  car.wheels.create # Check if `car` is persisted before creating a wheel.

  wheel = car.wheels.new
  wheel.save # Doesn't check if `car` is persisted
  ```

  ### Solution

  The original reason why I modified `#create` is because it doesn't
  allow to get the result of the transaction status within
  a nested transaction. The documentation explains it and mention
  to raise a rollback so that the outer transaction sees it but it misses
  an important detail: How to know whether the inner transaction was
  sucessfull since the Rollback error is silently swallowed.

  https://github.com/rails/rails/blob/b97917da8a801bf5360c3a9da913415bc8582735/activerecord/lib/active_record/transactions.rb#L159-L165

  A very simple example:

  ```ruby
  class Car < ApplicationRecord
    after_save do
      raise ActiveRecord::Rollback
    end
  end

  Car.transaction do
    car = Car.create!
    puts car.persisted? # Returns true. That's not correct.
  end
  ```

  The solution in this patch is to provide a flag on the record to know
  whether the last transaction was succesful.

Author: Edouard-chin

activerecord/lib/active_record/relation.rb

@@ -274,8 +274,8 @@ def create_or_find_by(attributes, &block)
       with_connection do |connection|
         record = nil
         transaction(requires_new: true) do
-          record = new(attributes, &block)
-          record.save || raise(ActiveRecord::Rollback)
+          record = create(attributes, &block)
+          record._last_transaction_return_status || raise(ActiveRecord::Rollback)
         end
         record
       rescue ActiveRecord::RecordNotUnique
@@ -294,8 +294,8 @@ def create_or_find_by!(attributes, &block)
       with_connection do |connection|
         record = nil
         transaction(requires_new: true) do
-          record = new(attributes, &block)
-          record.save! || raise(ActiveRecord::Rollback)
+          record = create!(attributes, &block)
+          record._last_transaction_return_status || raise(ActiveRecord::Rollback)
         end
         record
       rescue ActiveRecord::RecordNotUnique

activerecord/lib/active_record/transactions.rb

@@ -13,7 +13,7 @@ module Transactions
                        scope: [:kind, :name]
     end
 
-    attr_accessor :_new_record_before_last_commit # :nodoc:
+    attr_accessor :_new_record_before_last_commit, :_last_transaction_return_status # :nodoc:
 
     # = Active Record \Transactions
     #
@@ -436,6 +436,7 @@ def with_transaction_returning_status
           status = yield
           raise ActiveRecord::Rollback unless status
         end
+        @_last_transaction_return_status = status
         status
       end
     end
@@ -451,6 +452,7 @@ def trigger_transactional_callbacks? # :nodoc:
       def init_internals
         super
         @_start_transaction_state = nil
+        @_last_transaction_status = nil
         @_committed_already_called = nil
         @_new_record_before_last_commit = nil
       end

activerecord/test/cases/relations_test.rb

@@ -26,6 +26,7 @@
 require "models/category"
 require "models/categorization"
 require "models/edge"
+require "models/wheel"
 require "models/subscriber"
 require "models/cpk"
 
@@ -1611,6 +1612,15 @@ def test_create_or_find_by_bang_rollbacks_a_transaction
     end
   end
 
+  def test_create_or_find_by_on_a_collections_rollbacks_a_transaction_when_owner_is_not_persisted
+    car = BrokenCar.create(name: "Civic")
+    assert_not_predicate(car, :persisted?)
+
+    assert_raises(ActiveRecord::RecordNotSaved) do
+      car.wheels.create_or_find_by!(size: 1500)
+    end
+  end
+
   def test_create_or_find_by_with_block
     assert_nil Subscriber.find_by(nick: "bob")