Bug #47412: Valgrind warnings / user can read uninitalized memory using

SP variables

A function call may end without throwing an error or without setting 
the return value. This can happen when e.g. an error occurs while 
calculating the return value.

Fixed by setting the value to NULL when error occurs during evaluation
of an expression.

mysql-test/t/sp-bugs.test

@@ -0,0 +1,61 @@
+# Test file for stored procedure bugfixes
+
+--echo #
+--echo # Bug #47412: Valgrind warnings / user can read uninitalized memory
+--echo # using SP variables
+--echo #
+
+CREATE SCHEMA testdb;
+USE testdb;
+DELIMITER |;
+CREATE FUNCTION f2 () RETURNS INTEGER
+BEGIN
+   DECLARE CONTINUE HANDLER FOR SQLSTATE '42000' SET @aux = 1;
+   RETURN f_not_exists () ;
+END|
+CREATE PROCEDURE p3 ( arg1 VARCHAR(32) )
+BEGIN
+   CALL p_not_exists ( );
+END|
+DELIMITER ;|
+--echo # should not return valgrind warnings
+--error ER_SP_DOES_NOT_EXIST
+CALL p3 ( f2 () );
+
+DROP SCHEMA testdb;
+
+CREATE SCHEMA testdb;
+USE testdb;
+DELIMITER |;
+CREATE FUNCTION f2 () RETURNS INTEGER
+BEGIN
+   DECLARE CONTINUE HANDLER FOR SQLSTATE '42000' SET @aux = 1;
+   RETURN f_not_exists () ;
+END|
+CREATE PROCEDURE p3 ( arg2 INTEGER )
+BEGIN
+   CALL p_not_exists ( );
+END|
+DELIMITER ;|
+--echo # should not return valgrind warnings
+--error ER_SP_DOES_NOT_EXIST
+CALL p3 ( f2 () );
+
+DROP SCHEMA testdb;
+
+CREATE SCHEMA testdb;
+USE testdb;
+DELIMITER |;
+CREATE FUNCTION f2 () RETURNS INTEGER
+BEGIN
+   DECLARE CONTINUE HANDLER FOR SQLSTATE '42000' SET @aux = 1;
+   RETURN f_not_exists () ;
+END|
+DELIMITER ;|
+--echo # should not return valgrind warnings
+SELECT f2 ();
+
+DROP SCHEMA testdb;
+
+
+--echo End of 5.1 tests