MDEV-32875 SERVER_STATUS_AUTOCOMMIT set after connecting, if autocommit=0

After successful connection, server always sets SERVER_STATUS_AUTOCOMMIT
in server_status in the OK packet. This is wrong, if global variable
autocommit=0.

Fixed THD::init(), added mysql_client_test test.

Thanks to Diego Dupin for the providing the patch.
Signed-off-by: Vladislav Vaintroub <vvaintroub@gmail.com>

sql/sql_class.cc

@@ -1227,7 +1227,9 @@ void THD::init()
 
   user_time.val= start_time= start_time_sec_part= 0;
 
-  server_status= SERVER_STATUS_AUTOCOMMIT;
+  server_status= 0;
+  if (variables.option_bits & OPTION_AUTOCOMMIT)
+    server_status|= SERVER_STATUS_AUTOCOMMIT;
   if (variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES)
     server_status|= SERVER_STATUS_NO_BACKSLASH_ESCAPES;
   if (variables.sql_mode & MODE_ANSI_QUOTES)

tests/mysql_client_test.c

@@ -21770,6 +21770,44 @@ static void test_mdev_30159()
   myquery(rc);
 }
 
+/*
+  Check that server_status returned after connecting to server
+  is consistent with the value of autocommit variable.
+*/
+static void test_connect_autocommit()
+{
+  int rc;
+  my_bool autocommit[]= {0, 1};
+  int i;
+  rc= mysql_query(mysql, "SET @save_autocommit=@@global.autocommit");
+  myquery(rc);
+  for (i= 0; i < 2; i++)
+  {
+    MYSQL *con;
+    char query[100];
+    int autocommit_val;
+
+    con= mysql_client_init(NULL);
+    DIE_UNLESS(con);
+    autocommit_val = autocommit[i];
+    snprintf(query, sizeof(query), "SET global autocommit=%d", autocommit_val);
+    rc= mysql_query(mysql, query);
+    myquery(rc);
+
+    if (!(mysql_real_connect(con, opt_host, opt_user, opt_password, current_db,
+                             opt_port, opt_unix_socket, 0)))
+    {
+      fprintf(stderr, "Failed to connect to database: Error: %s\n",
+              mysql_error(con));
+      exit(1);
+    }
+    DIE_UNLESS(!!(con->server_status & SERVER_STATUS_AUTOCOMMIT) == autocommit_val);
+    mysql_close(con);
+  }
+  rc= mysql_query(mysql, "SET global autocommit=@save_autocommit");
+  myquery(rc);
+}
+
 static struct my_tests_st my_tests[]= {
   { "test_mdev_20516", test_mdev_20516 },
   { "test_mdev24827", test_mdev24827 },
@@ -22074,6 +22112,7 @@ static struct my_tests_st my_tests[]= {
   { "test_mdev18408", test_mdev18408 },
   { "test_mdev20261", test_mdev20261 },
   { "test_mdev_30159", test_mdev_30159 },
+  { "test_connect_autocommit", test_connect_autocommit},
   { 0, 0 }
 };