MDEV-37784 fix the warning

cannot add new warnings in 11.8 anymore:
* remove ER_WARN_DEFAULT_SYNTAX
* use ER_VARIABLE_IGNORED instead
* change the wording in it to be more generic
* simplified new_mode warning-printing code

(cherry picked from commit 399edc7)

Author: vuvova

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

@@ -15,11 +15,11 @@ SELECT @@session.new_mode;
 
 SET @@session.new_mode = "TEST_WARNING1";
 Warnings:
-Warning	4206	'TEST_WARNING1' is default and ignored
+Warning	4200	The setting 'new_mode=TEST_WARNING1' is ignored. It only exists for compatibility with old installations and will be removed in a future release
 SET @@session.new_mode = "TEST_WARNING1,TEST_WARNING2";
 Warnings:
-Warning	4206	'TEST_WARNING1' is default and ignored
-Warning	4206	'TEST_WARNING2' is default and ignored
+Warning	4200	The setting 'new_mode=TEST_WARNING1' is ignored. It only exists for compatibility with old installations and will be removed in a future release
+Warning	4200	The setting 'new_mode=TEST_WARNING2' is ignored. It only exists for compatibility with old installations and will be removed in a future release
 SET @@session.new_mode = "TEST_WARNING1,TEST_WARNING2,TEST_WARNING3";
 ERROR 42000: Variable 'new_mode' can't be set to the value of 'TEST_WARNING3'
 SET @@session.new_mode = "ALL";

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

@@ -0,0 +1,2 @@
+call mtr.add_suppression('new_mode=TEST_WARNING1');
+FOUND 1 /new_mode=TEST_WARNING1/ in mysqld.1.err

mysql-test/suite/sys_vars/t/new_mode_notembedded.opt

@@ -0,0 +1 @@
+--new-mode=TEST_WARNING1

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

@@ -0,0 +1,7 @@
+--source include/have_debug.inc
+--source include/not_embedded.inc
+
+call mtr.add_suppression('new_mode=TEST_WARNING1');
+--let SEARCH_PATTERN=new_mode=TEST_WARNING1
+--let SEARCH_FILE=$MYSQLTEST_VARDIR/log/mysqld.1.err
+--source include/search_pattern_in_file.inc

sql/mysqld.cc

@@ -4182,6 +4182,7 @@ static int init_common_variables()
   global_system_variables.lc_messages= my_default_lc_messages;
   global_system_variables.errmsgs= my_default_lc_messages->errmsgs->errmsgs;
   init_client_errs();
+  check_new_mode_value(NULL, &global_system_variables.new_behavior);
   mysql_library_init(unused,unused,unused); /* for replication */
   lex_init();
   if (item_create_init())
@@ -8733,8 +8734,6 @@ static int get_options(int *argc_ptr, char ***argv_ptr)
                       "release. Please use --old-mode instead. ");
   }
 
-  check_new_mode_value(NULL, &global_system_variables.new_behavior);
-
   if (global_system_variables.net_buffer_length > 
       global_system_variables.max_allowed_packet)
   {

sql/share/errmsg-utf8.txt

@@ -12277,7 +12277,7 @@ ER_SEQUENCE_TABLE_CANNOT_HAVE_ANY_CONSTRAINTS
 ER_SEQUENCE_TABLE_ORDER_BY
         eng "ORDER BY"
 ER_VARIABLE_IGNORED
-        eng "The variable '%s' is ignored. It only exists for compatibility with old installations and will be removed in a future release"
+        eng "The setting '%s' is ignored. It only exists for compatibility with old installations and will be removed in a future release"
 ER_INCORRECT_COLUMN_NAME_COUNT
         eng "Incorrect column name count for derived table"
         chi "派生表的列名计数不正确"
@@ -12292,8 +12292,3 @@ ER_VECTOR_FORMAT_INVALID
         eng "Invalid vector format at offset: %d for '%-.100s'. Must be a valid JSON array of numbers."
 ER_PSEUDO_THREAD_ID_OVERWRITE
         eng "Pseudo thread id should not be modified by the client as it will be overwritten"
-ER_WARN_DEFAULT_SYNTAX
-        chi "'%s' 默认并被忽略"
-        eng "'%s' is default and ignored"
-        ger "'%s' ist Standard und wird ignoriert"
-        spa "'%s' Es predeterminado e ignorado"

sql/sys_vars.cc

@@ -4091,19 +4091,10 @@ void check_new_mode_value(THD *thd, ulonglong *v)
   {
     if ((1ULL<<i) & vl)
     {
+      char buf1[NAME_CHAR_LEN*2 + 3];
+      strxnmov(buf1, sizeof(buf1)-1, "new_mode=", new_mode_default_names[i], 0);
+      my_error(ER_VARIABLE_IGNORED, MYF(ME_WARNING), buf1);
       (*v)&= ~(1ULL << (i+NEW_MODE_MAX));
-      if (thd)
-      {
-        push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
-                      ER_WARN_DEFAULT_SYNTAX,
-                      ER_THD(thd, ER_WARN_DEFAULT_SYNTAX),
-                      new_mode_default_names[i]);
-      }
-      else
-      {
-        sql_print_warning("--new-mode='%s' is now default",
-                          new_mode_default_names[i]);
-      }
     }
   }
 }