MDEV-27521 SIGSEGV in spider_parse_connect_info in MDEV-27106 branch

Add NULL check to SPIDER_OPTION_STR_LIST.

storage/spider/mysql-test/spider/feature/r/engine_defined_attributes.result

@@ -209,6 +209,13 @@ REMOTE_SERVER="s_2_2" REMOTE_DATABASE="auto_test_remote2"
 SELECT * FROM tbl_a;
 a	b
 DROP TABLE tbl_a;
+CREATE TABLE tbl_a (
+a INT
+) ENGINE=Spider DEFAULT CHARSET=utf8
+PARTITION BY HASH (a) PARTITIONS 2;
+SELECT * FROM tbl_a;
+ERROR HY000: Unable to connect to foreign data source: localhost
+DROP TABLE tbl_a;
 connection child2_1;
 DROP DATABASE auto_test_remote;
 connection child2_2;

storage/spider/mysql-test/spider/feature/t/engine_defined_attributes.test

@@ -194,6 +194,14 @@ PARTITION BY RANGE (a) (
 SELECT * FROM tbl_a;
 DROP TABLE tbl_a;
 
+eval CREATE TABLE tbl_a (
+  a INT
+) $MASTER_1_ENGINE $MASTER_1_CHARSET
+PARTITION BY HASH (a) PARTITIONS 2;
+--error ER_CONNECT_TO_FOREIGN_DATA_SOURCE
+SELECT * FROM tbl_a;
+DROP TABLE tbl_a;
+
 --connection child2_1
 DROP DATABASE auto_test_remote;
 

storage/spider/spd_table.cc

@@ -2015,7 +2015,7 @@ int st_spider_param_string_parse::print_param_error()
   corresponding attribute of SPIDER_SHARE.
 */
 #define SPIDER_OPTION_STR_LIST(title_name, option_name, param_name) \
-  if (option_struct->option_name)                                             \
+  if (option_struct && option_struct->option_name)                            \
   {                                                                           \
     DBUG_PRINT("info", ("spider " title_name " start overwrite"));            \
     share->SPIDER_PARAM_STR_CHARLEN(param_name)=                              \