Fix `insert_fixtures_set` to be restored original connection flags

#33363 has two regressions. First one is that `insert_fixtures_set` is
failed if flags is an array. Second one is that connection flags are not
restored if `set_server_option` is not supported.

1 files changed, 80 insertions, 5 deletions

diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index cdc9a8585f..a90b2440f9 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "cases/helper"
+require "support/connection_helper"
 require "models/admin"
 require "models/admin/account"
 require "models/admin/randomly_named_c1"
@@ -32,6 +33,8 @@ require "models/treasure"
 require "tempfile"
 
 class FixturesTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
   self.use_instantiated_fixtures = true
   self.use_transactional_tests = false
 
@@ -122,16 +125,88 @@ class FixturesTest < ActiveRecord::TestCase
         ]
       }
 
-      ActiveRecord::Base.transaction do
-        con = ActiveRecord::Base.connection
-        assert_equal 1, con.open_transactions
-        con.insert_fixtures_set(fixtures)
-        assert_equal 1, con.open_transactions
+      assert_difference "TrafficLight.count" do
+        ActiveRecord::Base.transaction do
+          conn = ActiveRecord::Base.connection
+          assert_equal 1, conn.open_transactions
+          conn.insert_fixtures_set(fixtures)
+          assert_equal 1, conn.open_transactions
+        end
       end
     end
   end
 
   if current_adapter?(:Mysql2Adapter)
+    def test_bulk_insert_with_multi_statements_enabled
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(
+          orig_connection.merge(flags: %w[MULTI_STATEMENTS])
+        )
+
+        fixtures = {
+          "traffic_lights" => [
+            { "location" => "US", "state" => ["NY"], "long_state" => ["a"] },
+          ]
+        }
+
+        ActiveRecord::Base.connection.stub(:supports_set_server_option?, false) do
+          assert_nothing_raised do
+            conn = ActiveRecord::Base.connection
+            conn.execute("SELECT 1; SELECT 2;")
+            conn.raw_connection.abandon_results!
+          end
+
+          assert_difference "TrafficLight.count" do
+            ActiveRecord::Base.transaction do
+              conn = ActiveRecord::Base.connection
+              assert_equal 1, conn.open_transactions
+              conn.insert_fixtures_set(fixtures)
+              assert_equal 1, conn.open_transactions
+            end
+          end
+
+          assert_nothing_raised do
+            conn = ActiveRecord::Base.connection
+            conn.execute("SELECT 1; SELECT 2;")
+            conn.raw_connection.abandon_results!
+          end
+        end
+      end
+    end
+
+    def test_bulk_insert_with_multi_statements_disabled
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(
+          orig_connection.merge(flags: [])
+        )
+
+        fixtures = {
+          "traffic_lights" => [
+            { "location" => "US", "state" => ["NY"], "long_state" => ["a"] },
+          ]
+        }
+
+        ActiveRecord::Base.connection.stub(:supports_set_server_option?, false) do
+          assert_raises(ActiveRecord::StatementInvalid) do
+            conn = ActiveRecord::Base.connection
+            conn.execute("SELECT 1; SELECT 2;")
+            conn.raw_connection.abandon_results!
+          end
+
+          assert_difference "TrafficLight.count" do
+            conn = ActiveRecord::Base.connection
+            conn.insert_fixtures_set(fixtures)
+          end
+
+          assert_raises(ActiveRecord::StatementInvalid) do
+            conn = ActiveRecord::Base.connection
+            conn.execute("SELECT 1; SELECT 2;")
+            conn.raw_connection.abandon_results!
+          end
+        end
+      end
+    end
+
     def test_insert_fixtures_set_raises_an_error_when_max_allowed_packet_is_smaller_than_fixtures_set_size
       conn = ActiveRecord::Base.connection
       mysql_margin = 2