Bug#44521 Executing a stored procedure as a prepared statement can sometimes cause

          an assertion in a debug build.

The reason is that the C API doesn't support multiple result sets for prepared
statements and attempting to execute a stored routine which returns multiple result
sets sometimes lead to a network error. The network error sets the diagnostic area
prematurely which later leads to the assert when an attempt is made to set a second
server state.

This patch fixes the issue by changing the scope of the error code returned by
sp_instr_stmt::execute() to include any error which happened during the execution.
To assure that Diagnostic_area::is_sent really mean that the message was sent all
network related functions are checked for return status.

libmysqld/lib_sql.cc:
  * Changed prototype to return success/failure status on net_send_error_packet(),
    net_send_ok(), net_send_eof(), write_eof_packet().
mysql-test/r/sp_notembedded.result:
  * Added test case for bug 44521
mysql-test/t/sp_notembedded.test:
  * Added test case for bug 44521
sql/protocol.cc:
  * Changed prototype to return success/failure status on net_send_error_packet(),
    net_send_ok(), net_send_eof(), write_eof_packet().
sql/protocol.h:
  * Changed prototype to return success/failure status on net_send_error_packet(),
    net_send_ok(), net_send_eof(), write_eof_packet().
sql/sp_head.cc:
  * Changed prototype to return success/failure status on net_send_error_packet(),
    net_send_ok(), net_send_eof(), write_eof_packet().

1 files changed, 36 insertions, 0 deletions

diff --git a/mysql-test/t/sp_notembedded.test b/mysql-test/t/sp_notembedded.test
index ecb37c1299c..f593e184ad2 100644
--- a/mysql-test/t/sp_notembedded.test
+++ b/mysql-test/t/sp_notembedded.test
@@ -380,3 +380,39 @@ set @@global.concurrent_insert= @old_concurrent_insert;
 # Wait till all disconnects are completed
 --source include/wait_until_count_sessions.inc
 
+
+--echo #
+--echo # Bug#44521 Prepared Statement: CALL p() - crashes: `! thd->main_da.is_sent' failed et.al.
+--echo #
+SELECT GET_LOCK('Bug44521', 0);
+--connect (con1,localhost,root,,)
+--echo ** Connection con1
+delimiter $;
+CREATE PROCEDURE p()
+BEGIN
+  SELECT 1;
+  SELECT GET_LOCK('Bug44521', 100);
+  SELECT 2;
+END$
+delimiter ;$
+--send CALL p();
+--connection default
+--echo ** Default connection
+let $wait_condition=
+  SELECT count(*) = 1 FROM information_schema.processlist
+  WHERE state = "User lock" AND info = "SELECT GET_LOCK('Bug44521', 100)";
+--source include/wait_condition.inc
+let $conid =
+  `SELECT id FROM information_schema.processlist
+   WHERE state = "User lock" AND info = "SELECT GET_LOCK('Bug44521', 100)"`;
+dirty_close con1;
+SELECT RELEASE_LOCK('Bug44521');
+let $wait_condition=
+  SELECT count(*) = 0 FROM information_schema.processlist
+  WHERE id = $conid;
+--source include/wait_condition.inc 
+DROP PROCEDURE p;
+
+--echo # ------------------------------------------------------------------
+--echo # -- End of 5.1 tests
+--echo # ------------------------------------------------------------------