Bug#8153 (Stored procedure with subquery and continue handler, wrong result)

Before this fix,
- a runtime error in a statement in a stored procedure with no error handlers
was properly detected (as expected)
- a runtime error in a statement with an error handler inherited from a non
local runtime context (i.e., proc a with a handler, calling proc b) was
properly detected (as expected)
- a runtime error in a statement with a *local* error handler was executed
as follows :
a) the statement would succeed, regardless of the error condition, (bug)
b) the error handler would be called (as expected).

The root cause is that functions like my_messqge_sql would "forget" to set
the thread flag thd->net.report_error to 1, because of the check involving
sp_rcontext::found_handler_here().
Failure to set this flag would cause, later in the call stack,
in Item_func::fix_fields() at line 190, the code to return FALSE and consider
that executing the statement was successful.

With this fix :
- error handling code, that was duplicated in different places in the code,
is now implemented in sp_rcontext::handle_error(),
- handle_error() correctly sets thd->net.report_error when a handler is
present, regardless of the handler location (local, or in the call stack).

A test case, bug8153_subselect, has been written to demonstrate the change
of behavior before and after the fix.

Another test case, bug8153_function_a, as also been writen.
This test has the same behavior before and after the fix.
This test has been written to demonstrate that the previous expected
result of procedure bug18787, was incorrect, since select no_such_function()
should fail and therefore not produce a result.

The incorrect result for bug18787 has the same root cause as Bug#8153,
and the expected result has been adjusted.


sql/mysqld.cc:
  Bug#8153, use sp_rcontext::handle_error() to handle errors.
sql/sql_error.cc:
  Bug#8153, use sp_rcontext::handle_error() to handle errors.
sql/protocol.cc:
  Bug#8153, use sp_rcontext::handle_error() to handle errors.
sql/sp_rcontext.h:
  Bug#8153, created helper sp_rcontext::handle_error() to handle errors.
sql/sp_rcontext.cc:
  Bug#8153, created helper sp_rcontext::handle_error() to handle errors.
mysql-test/t/sp.test:
  Bug#8153, added test cases.
mysql-test/r/sp.result:
  Bug#8153, added test cases, fixed expected result of bug18787.

1 files changed, 60 insertions, 2 deletions

diff --git a/mysql-test/r/sp.result b/mysql-test/r/sp.result
index 70d8a99c7c2..7e74cfffa94 100644
--- a/mysql-test/r/sp.result
+++ b/mysql-test/r/sp.result
@@ -4872,8 +4872,6 @@ declare continue handler for sqlexception begin end;
 select no_such_function();
 end|
 call bug18787()|
-no_such_function()
-NULL
 drop procedure bug18787|
 create database bug18344_012345678901|
 use bug18344_012345678901|
@@ -5220,6 +5218,66 @@ CHARSET(p2)	COLLATION(p2)
 cp1251	cp1251_general_ci
 CHARSET(p3)	COLLATION(p3)
 greek	greek_general_ci
+drop table if exists t3, t4, t5|
+drop procedure if exists bug8153_subselect|
+drop procedure if exists bug8153_function|
+create table t3 (a int)|
+create table t4 (a int)|
+insert into t3 values (1)|
+insert into t4 values (1), (1)|
+create procedure bug8153_subselect()
+begin
+declare continue handler for sqlexception
+begin
+select 'statement failed';
+end;
+update t3 set a=a+1 where (select a from t4 where a=1) is null;
+select 'statement after update';
+end|
+call bug8153_subselect()|
+statement failed
+statement failed
+statement after update
+statement after update
+select * from t3|
+a
+1
+call bug8153_subselect()|
+statement failed
+statement failed
+statement after update
+statement after update
+select * from t3|
+a
+1
+drop procedure bug8153_subselect|
+create procedure bug8153_function_a()
+begin
+declare continue handler for sqlexception
+begin
+select 'in continue handler';
+end;
+select 'reachable code a1';
+call bug8153_function_b();
+select 'reachable code a2';
+end|
+create procedure bug8153_function_b()
+begin
+select 'reachable code b1';
+select no_such_function();
+select 'unreachable code b2';
+end|
+call bug8153_function_a()|
+reachable code a1
+reachable code a1
+reachable code b1
+reachable code b1
+in continue handler
+in continue handler
+reachable code a2
+reachable code a2
+drop procedure bug8153_function_a|
+drop procedure bug8153_function_b|
 use test|
 DROP DATABASE mysqltest1|
 drop table t1,t2;