Merge pull request #20818 from jeremywadsack/use_transactional_fixtures_all_databases

Use notification to ensure that lazy-loaded model classes have transactions

2 files changed, 43 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 9b74c3a10f..1d9579f1a8 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -849,6 +849,21 @@ module ActiveRecord
 
         remove_connection(spec.name)
         owner_to_pool[spec.name] = ConnectionAdapters::ConnectionPool.new(spec)
+
+        message_bus = ActiveSupport::Notifications.instrumenter
+        payload = {
+          connection_id: object_id
+        }
+        if spec
+          payload[:class_name] = spec.name
+          payload[:config] = spec.config
+        end
+
+        message_bus.instrument('!connection.active_record', payload) do
+          owner_to_pool[spec.name] = ConnectionAdapters::ConnectionPool.new(spec)
+        end
+
+        owner_to_pool[spec.name]
       end
 
       # Returns true if there are any active connections among the connection
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 51bf12d0bf..6d142285cd 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -968,6 +968,7 @@ module ActiveRecord
       @fixture_cache = {}
       @fixture_connections = []
       @@already_loaded_fixtures ||= {}
+      @connection_subscriber = nil
 
       # Load fixtures once and begin transaction.
       if run_in_transaction?
@@ -977,10 +978,36 @@ module ActiveRecord
           @loaded_fixtures = load_fixtures(config)
           @@already_loaded_fixtures[self.class] = @loaded_fixtures
         end
+
+        # Begin transactions for connections already established
         @fixture_connections = enlist_fixture_connections
         @fixture_connections.each do |connection|
           connection.begin_transaction joinable: false
         end
+
+        # When connections are established in the future, begin a transaction too
+        @connection_subscriber = ActiveSupport::Notifications.subscribe('!connection.active_record') do |_, _, _, _, payload|
+          model_class = nil
+          begin
+            model_class = payload[:class_name].constantize if payload[:class_name]
+          rescue NameError
+            model_class = nil
+          end
+
+          if model_class
+            begin
+              connection = ActiveRecord::Base.connection_handler.retrieve_connection(model_class)
+            rescue ConnectionNotEstablished
+              connection = nil
+            end
+
+            if connection && !@fixture_connections.include?(connection)
+              connection.begin_transaction joinable: false
+              @fixture_connections << connection
+            end
+          end
+        end
+
       # Load fixtures for every test.
       else
         ActiveRecord::FixtureSet.reset_cache
@@ -995,6 +1022,7 @@ module ActiveRecord
     def teardown_fixtures
       # Rollback changes if a transaction is active.
       if run_in_transaction?
+        ActiveSupport::Notifications.unsubscribe(@connection_subscriber) if @connection_subscriber
         @fixture_connections.each do |connection|
           connection.rollback_transaction if connection.transaction_open?
         end