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, 21 insertions, 13 deletions

diff --git a/libmysqld/lib_sql.cc b/libmysqld/lib_sql.cc
index ec108bf372e..d4a200c07b2 100644
--- a/libmysqld/lib_sql.cc
+++ b/libmysqld/lib_sql.cc
@@ -803,11 +803,11 @@ MYSQL_DATA *THD::alloc_new_dataset()
 */
 
 static
-void
+bool
 write_eof_packet(THD *thd, uint server_status, uint total_warn_count)
 {
   if (!thd->mysql)            // bootstrap file handling
-    return;
+    return FALSE;
   /*
     The following test should never be true, but it's better to do it
     because if 'is_fatal_error' is set the server is not going to execute
@@ -822,6 +822,7 @@ write_eof_packet(THD *thd, uint server_status, uint total_warn_count)
   */
   thd->cur_data->embedded_info->warning_count=
     (thd->spcont ? 0 : min(total_warn_count, 65535));
+  return FALSE;
 }
 
 
@@ -1032,31 +1033,34 @@ bool Protocol_binary::write()
   @sa Server implementation of net_send_ok in protocol.cc for
   description of the arguments.
 
-  @return The function does not return errors.
+  @return
+    @retval TRUE An error occurred
+    @retval FALSE Success
 */
 
-void
+bool
 net_send_ok(THD *thd,
             uint server_status, uint total_warn_count,
             ha_rows affected_rows, ulonglong id, const char *message)
 {
   DBUG_ENTER("emb_net_send_ok");
   MYSQL_DATA *data;
+  bool error;
   MYSQL *mysql= thd->mysql;
 
   if (!mysql)            // bootstrap file handling
-    DBUG_VOID_RETURN;
+    DBUG_RETURN(FALSE);
   if (!(data= thd->alloc_new_dataset()))
-    return;
+    return TRUE;
   data->embedded_info->affected_rows= affected_rows;
   data->embedded_info->insert_id= id;
   if (message)
     strmake(data->embedded_info->info, message,
             sizeof(data->embedded_info->info)-1);
 
-  write_eof_packet(thd, server_status, total_warn_count);
+  error= write_eof_packet(thd, server_status, total_warn_count);
   thd->cur_data= 0;
-  DBUG_VOID_RETURN;
+  DBUG_RETURN(error);
 }
 
 
@@ -1065,18 +1069,21 @@ net_send_ok(THD *thd,
 
   @sa net_send_ok
 
-  @return This function does not return errors.
+  @return
+    @retval TRUE  An error occurred
+    @retval FALSE Success
 */
 
-void
+bool
 net_send_eof(THD *thd, uint server_status, uint total_warn_count)
 {
-  write_eof_packet(thd, server_status, total_warn_count);
+  bool error= write_eof_packet(thd, server_status, total_warn_count);
   thd->cur_data= 0;
+  return error;
 }
 
 
-void net_send_error_packet(THD *thd, uint sql_errno, const char *err)
+bool net_send_error_packet(THD *thd, uint sql_errno, const char *err)
 {
   MYSQL_DATA *data= thd->cur_data;
   struct embedded_query_result *ei;
@@ -1084,7 +1091,7 @@ void net_send_error_packet(THD *thd, uint sql_errno, const char *err)
   if (!thd->mysql)            // bootstrap file handling
   {
     fprintf(stderr, "ERROR: %d  %s\n", sql_errno, err);
-    return;
+    return TRUE;
   }
 
   if (!data)
@@ -1096,6 +1103,7 @@ void net_send_error_packet(THD *thd, uint sql_errno, const char *err)
   strmov(ei->sqlstate, mysql_errno_to_sqlstate(sql_errno));
   ei->server_status= thd->server_status;
   thd->cur_data= 0;
+  return FALSE;
 }