Bug#35103 mysql_client_test::test_bug29948 causes sporadic failures

The problem was that the COM_STMT_SEND_LONG_DATA was sending a response
packet if the prepared statement wasn't found in the server (due to
reconnection). The commands COM_STMT_SEND_LONG_DATA and COM_STMT_CLOSE
should not send any packets, even error packets should not be sent since
they are not expected by the client API.

The solution is to clear generated during the execution of the aforementioned
commands and to skip resend of prepared statement commands. Another fix is
that if the connection breaks during the send of prepared statement command,
the command is not sent again since the prepared statement is no longer in the
server.

1 files changed, 12 insertions, 5 deletions

diff --git a/libmysql/libmysql.c b/libmysql/libmysql.c
index 4afc3ec5925..b4fc40bc78a 100644
--- a/libmysql/libmysql.c
+++ b/libmysql/libmysql.c
@@ -2456,7 +2456,7 @@ static my_bool execute(MYSQL_STMT *stmt, char *packet, ulong length)
   int4store(buff+5, 1);                         /* iteration count */
 
   res= test(cli_advanced_command(mysql, COM_STMT_EXECUTE, buff, sizeof(buff),
-                                 packet, length, 1, NULL) ||
+                                 packet, length, 1, stmt) ||
             (*mysql->methods->read_query_result)(mysql));
   stmt->affected_rows= mysql->affected_rows;
   stmt->server_status= mysql->server_status;
@@ -2673,7 +2673,7 @@ stmt_read_row_from_cursor(MYSQL_STMT *stmt, unsigned char **row)
     int4store(buff + 4, stmt->prefetch_rows); /* number of rows to fetch */
     if ((*mysql->methods->advanced_command)(mysql, COM_STMT_FETCH,
                                             buff, sizeof(buff), NullS, 0,
-                                            1, NULL))
+                                            1, stmt))
     {
       set_stmt_errmsg(stmt, net->last_error, net->last_errno, net->sqlstate);
       return 1;
@@ -3340,7 +3340,7 @@ mysql_stmt_send_long_data(MYSQL_STMT *stmt, uint param_number,
     */
     if ((*mysql->methods->advanced_command)(mysql, COM_STMT_SEND_LONG_DATA,
                                             buff, sizeof(buff), data,
-                                            length, 1, NULL))
+                                            length, 1, stmt))
     {
       set_stmt_errmsg(stmt, mysql->net.last_error,
 		      mysql->net.last_errno, mysql->net.sqlstate);
@@ -4737,6 +4737,13 @@ int STDCALL mysql_stmt_store_result(MYSQL_STMT *stmt)
   MYSQL_DATA *result= &stmt->result;
   DBUG_ENTER("mysql_stmt_store_result");
 
+  if (!mysql)
+  {
+    /* mysql can be reset in mysql_close called from mysql_reconnect */
+    set_stmt_error(stmt, CR_SERVER_LOST, unknown_sqlstate);
+    DBUG_RETURN(1);
+  }
+
   mysql= mysql->last_used_con;
 
   if (!stmt->field_count)
@@ -4762,7 +4769,7 @@ int STDCALL mysql_stmt_store_result(MYSQL_STMT *stmt)
     int4store(buff, stmt->stmt_id);
     int4store(buff + 4, (int)~0); /* number of rows to fetch */
     if (cli_advanced_command(mysql, COM_STMT_FETCH, buff, sizeof(buff),
-                             NullS, 0, 1, NULL))
+                             NullS, 0, 1, stmt))
     {
       set_stmt_errmsg(stmt, net->last_error, net->last_errno, net->sqlstate);
       DBUG_RETURN(1);
@@ -4949,7 +4956,7 @@ static my_bool reset_stmt_handle(MYSQL_STMT *stmt, uint flags)
         char buff[MYSQL_STMT_HEADER]; /* packet header: 4 bytes for stmt id */
         int4store(buff, stmt->stmt_id);
         if ((*mysql->methods->advanced_command)(mysql, COM_STMT_RESET, buff,
-                                                sizeof(buff), 0, 0, 0, NULL))
+                                                sizeof(buff), 0, 0, 0, stmt))
         {
           set_stmt_errmsg(stmt, mysql->net.last_error, mysql->net.last_errno,
                           mysql->net.sqlstate);