Always respond to `set_server_option` since mysql2 0.5.0

https://github.com/brianmario/mysql2/pull/943
https://github.com/rails/rails/pull/37191

activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb

@@ -97,39 +97,27 @@ module ActiveRecord
             @connection.last_id
           end
 
-          def supports_set_server_option?
-            @connection.respond_to?(:set_server_option)
-          end
+          def multi_statements_enabled?
+            flags = @config[:flags]
 
-          def multi_statements_enabled?(flags)
             if flags.is_a?(Array)
               flags.include?("MULTI_STATEMENTS")
             else
-              (flags & Mysql2::Client::MULTI_STATEMENTS) != 0
+              flags.anybits?(Mysql2::Client::MULTI_STATEMENTS)
             end
           end
 
           def with_multi_statements
-            previous_flags = @config[:flags]
+            multi_statements_was = multi_statements_enabled?
 
-            unless multi_statements_enabled?(previous_flags)
-              if supports_set_server_option?
-                @connection.set_server_option(Mysql2::Client::OPTION_MULTI_STATEMENTS_ON)
-              else
-                @config[:flags] = Mysql2::Client::MULTI_STATEMENTS
-                reconnect!
-              end
+            unless multi_statements_was
+              @connection.set_server_option(Mysql2::Client::OPTION_MULTI_STATEMENTS_ON)
             end
 
             yield
           ensure
-            unless multi_statements_enabled?(previous_flags)
-              if supports_set_server_option?
-                @connection.set_server_option(Mysql2::Client::OPTION_MULTI_STATEMENTS_OFF)
-              else
-                @config[:flags] = previous_flags
-                reconnect!
-              end
+            unless multi_statements_was
+              @connection.set_server_option(Mysql2::Client::OPTION_MULTI_STATEMENTS_OFF)
             end
           end
 

activerecord/test/cases/fixtures_test.rb

@@ -147,28 +147,26 @@ class FixturesTest < ActiveRecord::TestCase
           ]
         }
 
-        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_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
+        assert_difference "TrafficLight.count" do
+          ActiveRecord::Base.transaction do
             conn = ActiveRecord::Base.connection
-            conn.execute("SELECT 1; SELECT 2;")
-            conn.raw_connection.abandon_results!
+            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
 
@@ -184,23 +182,21 @@ class FixturesTest < ActiveRecord::TestCase
           ]
         }
 
-        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_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_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
+        assert_raises(ActiveRecord::StatementInvalid) do
+          conn = ActiveRecord::Base.connection
+          conn.execute("SELECT 1; SELECT 2;")
+          conn.raw_connection.abandon_results!
         end
       end
     end