MDEV-29227 deprecate explicit_defaults_for_timestamp=0

mysql-test/main/type_timestamp.result

@@ -1326,6 +1326,8 @@ SET timestamp=DEFAULT;
 # MDEV-29225 make explicit_defaults_for_timestamps SESSION variable
 #
 set explicit_defaults_for_timestamp=OFF;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 create table t1 (f1 timestamp, f2 timestamp);
 show create table t1;
 Table	Create Table

mysql-test/suite/rpl/r/rpl_old_master_29078.result

@@ -48,6 +48,8 @@ ROLLBACK /* added by mysqlbinlog */;
 /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
 connection slave;
 set global explicit_defaults_for_timestamp=0;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 include/reset_slave.inc
 include/start_slave.inc
 show create table t1;

mysql-test/suite/rpl/r/rpl_parallel_29322.result

@@ -10,6 +10,8 @@ set @@session.explicit_defaults_for_timestamp = 1;
 connection slave;
 set @sav.explicit_defaults_for_timestamp   = @@global.explicit_defaults_for_timestamp;
 set global explicit_defaults_for_timestamp = 0;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 set @sav.slave_parallel_workers     = @@global.slave_parallel_workers;
 include/stop_slave.inc
 set @@global.slave_parallel_workers = 1;
@@ -105,6 +107,8 @@ connection slave;
 # B. alternate the master and slave vars' values to (0,1)
 connection master;
 set @@session.explicit_defaults_for_timestamp = 0;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 connection slave;
 set @@global.explicit_defaults_for_timestamp = 1;
 connection slave;

mysql-test/suite/rpl/r/rpl_timestamp.result

@@ -2,6 +2,8 @@ include/master-slave.inc
 [connection master]
 set timestamp=1656940000;
 set explicit_defaults_for_timestamp=!@@explicit_defaults_for_timestamp;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 connection master;
 create table t1 (f1 timestamp, f2 timestamp);
 show create table t1;

mysql-test/suite/sys_vars/inc/explicit_defaults_for_timestamp.inc

@@ -105,7 +105,9 @@ SET timestamp=DEFAULT;
 --echo #
 --echo # MDEV-29075 Changing explicit_defaults_for_timestamp within stored procedure works inconsistently
 --echo #
+--disable_warnings
 set statement explicit_defaults_for_timestamp=1-@@explicit_defaults_for_timestamp for create table t1 (ts timestamp);
+--enable_warnings
 show create table t1;
 drop table t1;
 

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

 set @@explicit_defaults_for_timestamp=0;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 CREATE TABLE t1 (a TIMESTAMP);
 SHOW CREATE TABLE t1;
 Table	Create Table
@@ -224,6 +226,8 @@ t1	CREATE TABLE `t1` (
   `a` timestamp NULL DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 set explicit_defaults_for_timestamp=1-@@explicit_defaults_for_timestamp;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 execute stmt;
 show create table t1;
 Table	Create Table

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

@@ -233,6 +233,8 @@ t1	CREATE TABLE `t1` (
   `a` timestamp NULL DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 set explicit_defaults_for_timestamp=1-@@explicit_defaults_for_timestamp;
+Warnings:
+Warning	1681	'explicit_defaults_for_timestamp=0' is deprecated and will be removed in a future release
 execute stmt;
 show create table t1;
 Table	Create Table

sql/sys_vars.cc

@@ -723,13 +723,24 @@ Sys_binlog_direct(
        CMD_LINE(OPT_ARG), DEFAULT(FALSE),
        NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(binlog_direct_check));
 
+static bool deprecated_explicit_defaults_for_timestamp(sys_var *self, THD *thd,
+                                                       set_var *var)
+{
+  if (var->value && var->save_result.ulonglong_value == 0)
+    push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
+                        ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT,
+                        ER_THD(thd, ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT),
+                        "explicit_defaults_for_timestamp=0"); // since 11.0.0
+  return false;
+}
 static Sys_var_bit Sys_explicit_defaults_for_timestamp(
        "explicit_defaults_for_timestamp",
        "This option causes CREATE TABLE to create all TIMESTAMP columns "
        "as NULL with DEFAULT NULL attribute, Without this option, "
        "TIMESTAMP columns are NOT NULL and have implicit DEFAULT clauses.",
        SESSION_VAR(option_bits), CMD_LINE(OPT_ARG),
-       OPTION_EXPLICIT_DEF_TIMESTAMP, DEFAULT(TRUE), NO_MUTEX_GUARD, IN_BINLOG);
+       OPTION_EXPLICIT_DEF_TIMESTAMP, DEFAULT(TRUE), NO_MUTEX_GUARD, IN_BINLOG,
+       ON_CHECK(deprecated_explicit_defaults_for_timestamp));
 
 static Sys_var_ulonglong Sys_bulk_insert_buff_size(
        "bulk_insert_buffer_size", "Size of tree cache used in bulk "