Bug#19356: Assert on undefined @uservar in prepared statement execute

The executing code had a safety assertion so that it refused to free Items
that it didn't create.  However, there is a case, undefined user variables,
which would put Items into the list to be freed.

Instead, do something that is more risky in expectation that the code will 
be refactored soon, as Kostja wants to do:  Remove the assertions from 
prepare() and execute().  Put one assertion at a higher level, before 
stmt->set_params_from_vars(), which may then create new to-be-freed Items .

1 files changed, 34 insertions, 0 deletions

diff --git a/mysql-test/t/ps_11bugs.test b/mysql-test/t/ps_11bugs.test
index ff1c87f3bd8..515bcc03c1a 100644
--- a/mysql-test/t/ps_11bugs.test
+++ b/mysql-test/t/ps_11bugs.test
@@ -144,3 +144,37 @@ prepare st_18492 from 'select * from t1 where 3 in (select (1+1) union select 1)
 execute st_18492;
 
 drop table t1;
+
+#
+# Bug#19356: Assertion failure with undefined @uservar in prepared statement execution
+# 
+create table t1 (a int, b varchar(4));
+create table t2 (a int, b varchar(4), primary key(a));
+
+prepare stmt1 from 'insert into t1 (a, b) values (?, ?)';
+prepare stmt2 from 'insert into t2 (a, b) values (?, ?)';
+
+set @intarg= 11;
+set @varchararg= '2222';
+execute stmt1 using @intarg, @varchararg;
+execute stmt2 using @intarg, @varchararg;
+set @intarg= 12;
+execute stmt1 using @intarg, @UNDEFINED;
+execute stmt2 using @intarg, @UNDEFINED;
+set @intarg= 13;
+execute stmt1 using @UNDEFINED, @varchararg;
+--error 1048
+execute stmt2 using @UNDEFINED, @varchararg;
+set @intarg= 14;
+set @nullarg= Null;
+execute stmt1 using @UNDEFINED, @nullarg;
+--error 1048
+execute stmt2 using @nullarg, @varchararg;
+
+select * from t1;
+select * from t2;
+
+drop table t1;
+drop table t2;
+
+--echo End of 5.0 tests.