MDEV-30727 Check spider_hton_ptr in spider udfs

UDF isn't supposed to use my_error(), it should return the error message in the provided error message buffer Fixes valgrind: ==93993== Conditional jump or move depends on uninitialised value(s) ==93993== at 0x484ECCD: strnlen (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so) ==93993== by 0x1AD2B2C: process_str_arg (my_vsnprintf.c:259) ==93993== by 0x1AD47E0: my_vsnprintf_ex (my_vsnprintf.c:696) ==93993== by 0x1A3B91E: my_error (my_error.c:120) ==93993== by 0xF87BE8: udf_handler::fix_fields(THD*, Item_func_or_sum*, unsigned int, Item**) (item_func.cc:3638) followup for 267dd5a

Author: vuvova

storage/spider/mysql-test/spider/bugfix/r/mdev_30727.result

@@ -1,12 +1,12 @@
 CREATE FUNCTION spider_direct_sql RETURNS INT SONAME 'ha_spider.so';
 SELECT spider_direct_sql ('SELECT * FROM s','a','srv "b"');
-ERROR HY000: Plugin 'SPIDER' is not loaded
+ERROR HY000: Can't initialize function 'spider_direct_sql'; Plugin 'SPIDER' is not loaded
 CREATE FUNCTION spider_bg_direct_sql RETURNS INT SONAME 'ha_spider.so';
 SELECT spider_bg_direct_sql ('SELECT * FROM s','a','srv "b"');
-ERROR HY000: Plugin 'SPIDER' is not loaded
+ERROR HY000: Can't initialize function 'spider_bg_direct_sql'; Plugin 'SPIDER' is not loaded
 CREATE FUNCTION spider_copy_tables RETURNS INT SONAME 'ha_spider.so';
 SELECT spider_copy_tables ('t', '0', '0');
-ERROR HY000: Plugin 'SPIDER' is not loaded
+ERROR HY000: Can't initialize function 'spider_copy_tables'; Plugin 'SPIDER' is not loaded
 CREATE FUNCTION spider_flush_table_mon_cache RETURNS INT SONAME 'ha_spider.so';
 SELECT spider_flush_table_mon_cache ();
 spider_flush_table_mon_cache ()

storage/spider/mysql-test/spider/bugfix/t/mdev_30727.test

@@ -1,13 +1,13 @@
 CREATE FUNCTION spider_direct_sql RETURNS INT SONAME 'ha_spider.so';
---error ER_PLUGIN_IS_NOT_LOADED
+--error ER_CANT_INITIALIZE_UDF
 SELECT spider_direct_sql ('SELECT * FROM s','a','srv "b"');
 
 CREATE FUNCTION spider_bg_direct_sql RETURNS INT SONAME 'ha_spider.so';
---error ER_PLUGIN_IS_NOT_LOADED
+--error ER_CANT_INITIALIZE_UDF
 SELECT spider_bg_direct_sql ('SELECT * FROM s','a','srv "b"');
 
 CREATE FUNCTION spider_copy_tables RETURNS INT SONAME 'ha_spider.so';
---error ER_PLUGIN_IS_NOT_LOADED
+--error ER_CANT_INITIALIZE_UDF
 SELECT spider_copy_tables ('t', '0', '0');
 
 # spider_flush_table_mon_cache does not require spider init to function

storage/spider/spd_copy_tables.cc

@@ -1154,9 +1154,6 @@ long long spider_copy_tables_body(
  DBUG_RETURN(0);
 }
 
-#undef my_error
-extern "C" void my_error(unsigned int nr, unsigned long MyFlags, ...);
-
 my_bool spider_copy_tables_init_body(
  UDF_INIT *initid,
  UDF_ARGS *args,
@@ -1165,7 +1162,7 @@ my_bool spider_copy_tables_init_body(
  DBUG_ENTER("spider_copy_tables_init_body");
  if (!spider_hton_ptr)
  {
- my_error(ER_PLUGIN_IS_NOT_LOADED, MYF(0), "SPIDER");
+ strcpy(message, "Plugin 'SPIDER' is not loaded");
  goto error;
  }
  if (args->arg_count != 3 && args->arg_count != 4)

storage/spider/spd_direct_sql.cc

@@ -1789,9 +1789,6 @@ long long spider_direct_sql_body(
  DBUG_RETURN(0);
 }
 
-#undef my_error
-extern "C" void my_error(unsigned int nr, unsigned long MyFlags, ...);
-
 my_bool spider_direct_sql_init_body(
  UDF_INIT *initid,
  UDF_ARGS *args,
@@ -1802,7 +1799,7 @@ my_bool spider_direct_sql_init_body(
  DBUG_ENTER("spider_direct_sql_init_body");
  if (!spider_hton_ptr)
  {
- my_error(ER_PLUGIN_IS_NOT_LOADED, MYF(0), "SPIDER");
+ strcpy(message, "Plugin 'SPIDER' is not loaded");
  goto error;
  }
  if (args->arg_count != 3)