MDEV-10431: Please implement mysqldump --add-drop-trigger from MySQL 5.6

Port of mysql changeset by Georgi Kodinov <Georgi.Kodinov@Oracle.com>:

    Bug #34325 : --add-drop-trigger option for mysqldump

    Implemented the --add-drop-trigger option to prepend each
    CREATE TRIGGER in the dump file with DROP TRIGGER.
    The option is off by default. Added a test case.

client/mysqldump.c

@@ -114,7 +114,8 @@ static my_bool  verbose= 0, opt_no_create_info= 0, opt_no_data= 0, opt_no_data_m
                 opt_slave_apply= 0, 
                 opt_include_master_host_port= 0,
                 opt_events= 0, opt_comments_used= 0,
-                opt_alltspcs=0, opt_notspcs= 0, opt_logging;
+                opt_alltspcs=0, opt_notspcs= 0, opt_logging,
+                opt_drop_trigger= 0 ;
 static my_bool insert_pat_inited= 0, debug_info_flag= 0, debug_check_flag= 0;
 static ulong opt_max_allowed_packet, opt_net_buffer_length;
 static MYSQL mysql_connection,*mysql=0;
@@ -233,6 +234,9 @@ static struct my_option my_long_options[] =
   {"add-drop-table", OPT_DROP, "Add a DROP TABLE before each create.",
    &opt_drop, &opt_drop, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0,
    0},
+  {"add-drop-trigger", 0, "Add a DROP TRIGGER before each create.",
+   &opt_drop_trigger, &opt_drop_trigger, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0,
+   0},
   {"add-locks", OPT_LOCKS, "Add locks around INSERT statements.",
    &opt_lock, &opt_lock, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0,
    0},
@@ -3281,6 +3285,10 @@ static void dump_trigger_old(FILE *sql_file, MYSQL_RES *show_triggers_rs,
   if (opt_compact)
     fprintf(sql_file, "/*!50003 SET @OLD_SQL_MODE=@@SQL_MODE*/;\n");
 
+  if (opt_drop_trigger)
+    fprintf(sql_file, "/*!50032 DROP TRIGGER IF EXISTS %s */;\n",
+    (*show_trigger_row)[0]);
+
   fprintf(sql_file,
           "DELIMITER ;;\n"
           "/*!50003 SET SESSION SQL_MODE=\"%s\" */;;\n"
@@ -3361,6 +3369,10 @@ static int dump_trigger(FILE *sql_file, MYSQL_RES *show_create_trigger_rs,
 
     switch_sql_mode(sql_file, ";", row[1]);
 
+    if (opt_drop_trigger)
+      fprintf(sql_file, "/*!50032 DROP TRIGGER IF EXISTS %s */;\n",
+          row[0]);
+
     query_str= cover_definer_clause(row[2], strlen(row[2]),
                                     C_STRING_WITH_LEN("50017"),
                                     C_STRING_WITH_LEN("50003"),

mysql-test/r/mysqldump.result

@@ -5534,3 +5534,52 @@ USE `db1`;
 DROP DATABASE db1;
 DROP DATABASE db2;
 FOUND 1 /Database: mysql/ in bug11505.sql
+#
+# Test for --add-drop-trigger
+#
+use test;
+CREATE TABLE t1 (a int, b int);
+CREATE TRIGGER tt1_t1 BEFORE INSERT ON t1 FOR EACH ROW 
+SET NEW.b=NEW.a + 10;
+INSERT INTO t1 (a) VALUES (1),(2),(3);
+
+/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
+/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
+/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
+/*!40101 SET NAMES utf8 */;
+/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
+/*!40103 SET TIME_ZONE='+00:00' */;
+/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
+/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
+/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
+
+CREATE DATABASE /*!32312 IF NOT EXISTS*/ `test` /*!40100 DEFAULT CHARACTER SET latin1 */;
+
+USE `test`;
+/*!50003 SET @saved_cs_client      = @@character_set_client */ ;
+/*!50003 SET @saved_cs_results     = @@character_set_results */ ;
+/*!50003 SET @saved_col_connection = @@collation_connection */ ;
+/*!50003 SET character_set_client  = utf8 */ ;
+/*!50003 SET character_set_results = utf8 */ ;
+/*!50003 SET collation_connection  = utf8_general_ci */ ;
+/*!50003 SET @saved_sql_mode       = @@sql_mode */ ;
+/*!50003 SET sql_mode              = '' */ ;
+/*!50032 DROP TRIGGER IF EXISTS tt1_t1 */;
+DELIMITER ;;
+/*!50003 CREATE*/ /*!50017 DEFINER=`root`@`localhost`*/ /*!50003 TRIGGER tt1_t1 BEFORE INSERT ON t1 FOR EACH ROW 
+SET NEW.b=NEW.a + 10 */;;
+DELIMITER ;
+/*!50003 SET sql_mode              = @saved_sql_mode */ ;
+/*!50003 SET character_set_client  = @saved_cs_client */ ;
+/*!50003 SET character_set_results = @saved_cs_results */ ;
+/*!50003 SET collation_connection  = @saved_col_connection */ ;
+/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
+
+/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
+/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
+/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
+/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
+/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
+/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
+
+DROP TABLE t1;

mysql-test/t/mysqldump.test

@@ -2582,3 +2582,15 @@ let SEARCH_FILE=$MYSQLTEST_VARDIR/tmp/bug11505.sql;
 let SEARCH_PATTERN=Database: mysql;
 exec $MYSQL_DUMP mysql func  > $SEARCH_FILE;
 source include/search_pattern_in_file.inc;
+
+--echo #
+--echo # Test for --add-drop-trigger
+--echo #
+use test;
+CREATE TABLE t1 (a int, b int);
+CREATE TRIGGER tt1_t1 BEFORE INSERT ON t1 FOR EACH ROW 
+  SET NEW.b=NEW.a + 10;
+
+INSERT INTO t1 (a) VALUES (1),(2),(3);
+--exec $MYSQL_DUMP --triggers --no-data --no-create-info --add-drop-trigger --skip-comments --databases test
+DROP TABLE t1;