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, 10 insertions, 6 deletions

diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 18cfd8d7dfc..207183f567c 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -2516,7 +2516,7 @@ void mysql_stmt_close(THD *thd, char *packet)
   DBUG_ENTER("mysql_stmt_close");
 
   if (!(stmt= find_prepared_statement(thd, stmt_id, "mysql_stmt_close")))
-    DBUG_VOID_RETURN;
+    goto out;
 
   /*
     The only way currently a statement can be deallocated when it's
@@ -2525,6 +2525,9 @@ void mysql_stmt_close(THD *thd, char *packet)
   DBUG_ASSERT(! (stmt->flags & (uint) Prepared_statement::IS_IN_USE));
   (void) stmt->deallocate();
 
+out:
+  /* clear errors, response packet is not expected */
+  thd->clear_error();
   DBUG_VOID_RETURN;
 }
 
@@ -2591,10 +2594,7 @@ void mysql_stmt_get_longdata(THD *thd, char *packet, ulong packet_length)
 #ifndef EMBEDDED_LIBRARY
   /* Minimal size of long data packet is 6 bytes */
   if (packet_length <= MYSQL_LONG_DATA_HEADER)
-  {
-    my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_stmt_send_long_data");
-    DBUG_VOID_RETURN;
-  }
+    goto out;
 #endif
 
   stmt_id= uint4korr(packet);
@@ -2614,7 +2614,7 @@ void mysql_stmt_get_longdata(THD *thd, char *packet, ulong packet_length)
     stmt->last_errno= ER_WRONG_ARGUMENTS;
     sprintf(stmt->last_error, ER(ER_WRONG_ARGUMENTS),
             "mysql_stmt_send_long_data");
-    DBUG_VOID_RETURN;
+    goto out;
   }
 #endif
 
@@ -2630,6 +2630,10 @@ void mysql_stmt_get_longdata(THD *thd, char *packet, ulong packet_length)
     stmt->last_errno= ER_OUTOFMEMORY;
     sprintf(stmt->last_error, ER(ER_OUTOFMEMORY), 0);
   }
+
+out:
+  /* clear errors, response packet is not expected */
+  thd->clear_error();
   DBUG_VOID_RETURN;
 }