MDEV-33270 Failure to call SP invoking another SP with parameter requiring type conversion

This patch corrects the fix for MDEV-32569. The latter has not taken into
account the fact not each statement uses the SELECT_LEX structure. In
particular CALL statements do not use such structure. However the parameter
passed to the stored procedure used in such a statement may require an
invocation of Type_std_attributes::agg_item_set_converter().

Approved by Oleksandr Byelkin <sanja@mariadb.com>

mysql-test/main/sp.result

@@ -8960,5 +8960,20 @@ DROP FUNCTION f1;
 DROP FUNCTION f2;
 DROP FUNCTION f3;
 DROP VIEW v1;
+#
+# MDEV-33270: Call of SP invoking another SP with a parameter
+#             requiring type conversion
+#
+SET NAMES latin1;
+CREATE PROCEDURE p1 (a text) BEGIN SELECT a; END |
+CREATE PROCEDURE p2 () CALL p1(concat('x',_utf8'x')) |
+CALL p2();
+a
+xx
+CALL p2();
+a
+xx
+DROP PROCEDURE p1;
+DROP PROCEDURE p2;
 # End of 10.4 tests
 #

mysql-test/main/sp.test

@@ -10567,5 +10567,25 @@ DROP FUNCTION f2;
 DROP FUNCTION f3;
 DROP VIEW v1;
 
+--echo #
+--echo # MDEV-33270: Call of SP invoking another SP with a parameter
+--echo #             requiring type conversion
+--echo #
+
+SET NAMES latin1;
+
+--delimiter |
+
+CREATE PROCEDURE p1 (a text) BEGIN SELECT a; END |
+CREATE PROCEDURE p2 () CALL p1(concat('x',_utf8'x')) |
+
+--delimiter ;
+
+CALL p2();
+CALL p2();
+
+DROP PROCEDURE p1;
+DROP PROCEDURE p2;
+
 --echo # End of 10.4 tests
 --echo #

sql/item.cc

@@ -2586,7 +2586,10 @@ bool Type_std_attributes::agg_item_set_converter(const DTCollation &coll,
       return TRUE;
 
     if (!thd->stmt_arena->is_conventional() &&
-        thd->lex->current_select->first_cond_optimization)
+	((!thd->lex->current_select &&
+	  (thd->stmt_arena->is_stmt_prepare_or_first_sp_execute() ||
+           thd->stmt_arena->is_stmt_prepare_or_first_stmt_execute())) ||
+         thd->lex->current_select->first_cond_optimization))
     {
       Query_arena *arena, backup;
       arena= thd->activate_stmt_arena_if_needed(&backup);