MDEV-27837: Disallow SET @@session.server_id within transaction

mysql-test/suite/sys_vars/r/set_server_id_inside_transaction.result

@@ -0,0 +1,76 @@
+CREATE TABLE t1 (a INT) ENGINE=InnoDB;
+#
+# Test that SET @@session.server_id fails inside explicit transaction
+#
+BEGIN;
+INSERT INTO t1 VALUES (1);
+SET @@session.server_id = 100;
+ERROR HY000: Cannot set @@session.server_id within a transaction
+ROLLBACK;
+#
+# Test that SET @@session.server_id works outside transaction
+#
+SET @@session.server_id = 100;
+SELECT @@session.server_id;
+@@session.server_id
+100
+#
+# Test that SET @@session.server_id fails with autocommit=0
+#
+SET autocommit = 0;
+INSERT INTO t1 VALUES (2);
+SET @@session.server_id = 200;
+ERROR HY000: Cannot set @@session.server_id within a transaction
+ROLLBACK;
+SET autocommit = 1;
+#
+# Test that SET @@session.server_id works after COMMIT
+#
+BEGIN;
+INSERT INTO t1 VALUES (3);
+COMMIT;
+SET @@session.server_id = 300;
+SELECT @@session.server_id;
+@@session.server_id
+300
+#
+# Test that SET @@session.server_id fails inside a trigger
+#
+CREATE TABLE t2 (a INT) ENGINE=InnoDB;
+CREATE TRIGGER tr1 BEFORE INSERT ON t2 FOR EACH ROW
+SET @@session.server_id = 100;
+INSERT INTO t2 VALUES (1);
+ERROR HY000: Cannot set @@session.server_id within a trigger or stored program
+DROP TRIGGER tr1;
+DROP TABLE t2;
+#
+# Test that SET @@session.server_id fails inside a stored procedure
+# called within a transaction
+#
+CREATE PROCEDURE sp1()
+BEGIN
+SET @@session.server_id = 100;
+END//
+BEGIN;
+CALL sp1();
+ERROR HY000: Cannot set @@session.server_id within a transaction
+ROLLBACK;
+DROP PROCEDURE sp1;
+#
+# Test that SET @@session.server_id fails inside a stored procedure
+# that starts its own transaction
+#
+CREATE PROCEDURE sp2()
+BEGIN
+START TRANSACTION;
+INSERT INTO t1 VALUES (1);
+SET @@session.server_id = 100;
+COMMIT;
+END//
+CALL sp2();
+ERROR HY000: Cannot set @@session.server_id within a transaction
+DROP PROCEDURE sp2;
+#
+# Cleanup
+#
+DROP TABLE t1;

mysql-test/suite/sys_vars/t/set_server_id_inside_transaction.test

@@ -0,0 +1,94 @@
+--source include/have_innodb.inc
+
+#
+# MDEV-27837: Disallow SET @@session.server_id within transaction
+#
+
+CREATE TABLE t1 (a INT) ENGINE=InnoDB;
+
+--echo #
+--echo # Test that SET @@session.server_id fails inside explicit transaction
+--echo #
+BEGIN;
+INSERT INTO t1 VALUES (1);
+--error ER_CANT_SET_SERVER_ID_IN_TRANSACTION
+SET @@session.server_id = 100;
+ROLLBACK;
+
+--echo #
+--echo # Test that SET @@session.server_id works outside transaction
+--echo #
+SET @@session.server_id = 100;
+SELECT @@session.server_id;
+
+--echo #
+--echo # Test that SET @@session.server_id fails with autocommit=0
+--echo #
+SET autocommit = 0;
+INSERT INTO t1 VALUES (2);
+--error ER_CANT_SET_SERVER_ID_IN_TRANSACTION
+SET @@session.server_id = 200;
+ROLLBACK;
+SET autocommit = 1;
+
+--echo #
+--echo # Test that SET @@session.server_id works after COMMIT
+--echo #
+BEGIN;
+INSERT INTO t1 VALUES (3);
+COMMIT;
+SET @@session.server_id = 300;
+SELECT @@session.server_id;
+
+--echo #
+--echo # Test that SET @@session.server_id fails inside a trigger
+--echo #
+CREATE TABLE t2 (a INT) ENGINE=InnoDB;
+CREATE TRIGGER tr1 BEFORE INSERT ON t2 FOR EACH ROW
+    SET @@session.server_id = 100;
+--error ER_CANT_SET_SERVER_ID_IN_SUBSTATEMENT
+INSERT INTO t2 VALUES (1);
+DROP TRIGGER tr1;
+DROP TABLE t2;
+
+--echo #
+--echo # Test that SET @@session.server_id fails inside a stored procedure
+--echo # called within a transaction
+--echo #
+--delimiter //
+
+CREATE PROCEDURE sp1()
+BEGIN
+  SET @@session.server_id = 100;
+END//
+
+--delimiter ;
+
+BEGIN;
+--error ER_CANT_SET_SERVER_ID_IN_TRANSACTION
+CALL sp1();
+ROLLBACK;
+DROP PROCEDURE sp1;
+
+--echo #
+--echo # Test that SET @@session.server_id fails inside a stored procedure
+--echo # that starts its own transaction
+--echo #
+--delimiter //
+CREATE PROCEDURE sp2()
+BEGIN
+  START TRANSACTION;
+  INSERT INTO t1 VALUES (1);
+  SET @@session.server_id = 100;
+  COMMIT;
+END//
+--delimiter ;
+--error ER_CANT_SET_SERVER_ID_IN_TRANSACTION
+CALL sp2();
+DROP PROCEDURE sp2;
+
+--echo #
+--echo # Cleanup
+--echo #
+DROP TABLE t1;
+

sql/share/errmsg-utf8.txt

@@ -10036,3 +10036,7 @@ ER_REMOVED_ORPHAN_TRIGGER
 ER_STORAGE_ENGINE_DISABLED
         eng "Storage engine %s is disabled"
         spa "El motor de almacenaje %s está desactivado"
+ER_CANT_SET_SERVER_ID_IN_TRANSACTION
+        eng "Cannot set @@session.server_id within a transaction"
+ER_CANT_SET_SERVER_ID_IN_SUBSTATEMENT
+        eng "Cannot set @@session.server_id within a trigger or stored program"

sql/sys_vars.cc

@@ -3375,6 +3375,13 @@ static bool check_server_id(sys_var *self, THD *thd, set_var *var)
     return true;
   }
 #endif /* WITH_WSREP */
+
+  if (error_if_in_trans_or_substatement(
+        thd,
+        ER_CANT_SET_SERVER_ID_IN_SUBSTATEMENT,
+        ER_CANT_SET_SERVER_ID_IN_TRANSACTION))
+    return true;
+
   return false;
 }