* Reset the warning_count and server_status flags if CLIENT_DEPRECATE…

…_EOF is enabled and the query yields a result set, preventing carry forwarding of flag values from the previous query.

* Suppress the display of warning counts in the "SHOW WARNINGS" statement.

deps/mariadb-client-library/client_deprecate_eof.patch

@@ -394,7 +394,7 @@ index e475e25..1a04b2f 100644
    }
    prev_pos= 0;				/* allowed to write at packet[-1] */
    pos=mysql->net.read_pos;
-@@ -1077,6 +1154,85 @@ int mthd_my_read_one_row(MYSQL *mysql,uint fields,MYSQL_ROW row, ulong *lengths)
+@@ -1077,6 +1154,93 @@ int mthd_my_read_one_row(MYSQL *mysql,uint fields,MYSQL_ROW row, ulong *lengths)
    return 0;
  }
 
@@ -443,13 +443,21 @@ index e475e25..1a04b2f 100644
 +        if (unpack_field(mysql, mem_root, 0, &m_rows, m_fields++))
 +          return NULL;
 +    }
-+    // read EOF packet in case of client not supporting 'CLIENT_DEPRECATE_EOF'
-+    if (!(mysql->server_capabilities & CLIENT_DEPRECATE_EOF))
-+    {
++    if (mysql->server_capabilities & CLIENT_DEPRECATE_EOF) {
++      // When the `CLIENT_DEPRECATE_EOF` flag is enabled, there is no intermediate EOF marker following field metadata.
++      // As a result, we cannot retrieve warning_count and server_status until all rows have been fetched.
++      // To prevent carrying forward previous query results, we simply reset warning_count and server_status at this point.
++      // ** It is crucial to refrain from using warning_count or server_status immediately after calling mysql_query/mysql_real_query*
++      // when the result yields a result set. Instead, verify these values after fetching all rows.
++      // The essential information is contained in the final OK packet, enabling accurate extraction of
++      // warning_count and server_status.
++      mysql->warning_count = 0;
++      mysql->server_status = 0;
++    } else {
++      // read EOF packet in case of client not supporting 'CLIENT_DEPRECATE_EOF'
 +      // read the EOF packet
 +      if (packet_error == ma_net_safe_read(mysql, NULL))
 +          return 0;
-+
 +      // verify it's actually an EOF packet
 +      if (*(mysql->net.read_pos) == 254)
 +      {

include/MySQL_Protocol.h

@@ -51,7 +51,7 @@ class MySQL_ResultSet {
 	unsigned int add_row(MYSQL_ROWS *rows);
 	unsigned int add_row(MYSQL_ROW row);
 	unsigned int add_row2(MYSQL_ROWS *row, unsigned char *offset);
-	void add_eof();
+	void add_eof(bool show_warning=false);
 	void remove_last_eof();
 	void add_err(MySQL_Data_Stream *_myds);
 	bool get_resultset(PtrSizeArray *PSarrayFinal);

lib/MySQL_Protocol.cpp

@@ -2990,7 +2990,7 @@ unsigned int MySQL_ResultSet::add_row2(MYSQL_ROWS *row, unsigned char *offset) {
 	return length;
 }
 
-void MySQL_ResultSet::add_eof() {
+void MySQL_ResultSet::add_eof(bool show_warning) {
 	if (myprot) {
 		unsigned int nTrx=myds->sess->NumActiveTransactions();
 		uint16_t setStatus = (nTrx ? SERVER_STATUS_IN_TRANS : 0 );
@@ -3007,7 +3007,7 @@ void MySQL_ResultSet::add_eof() {
 		const MySQL_Data_Stream* _server_myds = (_mybe && _mybe->server_myds) ? _mybe->server_myds : nullptr;
 		const MySQL_Connection* _myconn = (_server_myds && _server_myds->myds_type == MYDS_BACKEND && _server_myds->myconn) ?
 			_server_myds->myconn : nullptr;
-		const unsigned int warning_count = (_myconn) ? _myconn->warning_count : 0;
+		const unsigned int warning_count = (show_warning == false && _myconn) ? _myconn->warning_count : 0;
 		if (deprecate_eof_active) {
 			PtrSize_t pkt;
 			buffer_to_PSarrayOut();

lib/MySQL_Session.cpp

@@ -8168,13 +8168,16 @@ void MySQL_Session::reset_warning_hostgroup_flag_and_release_connection()
 		// if we've reached this point, it means that warning was found in the previous query, but the
 		// current executed query is not 'SHOW WARNINGS' or 'SHOW COUNT(*) FROM WARNINGS', so we can safely reset warning_in_hg and 
 		// return connection back to the connection pool.
-		MySQL_Backend* _mybe = NULL;
-		_mybe = find_backend(warning_in_hg);
-		MySQL_Data_Stream* myds = _mybe->server_myds;
-		myds->myconn->warning_count = 0;
-		myds->myconn->set_status(false, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
-		if ((myds->myconn->reusable == true) && myds->myconn->IsActiveTransaction() == false && myds->myconn->MultiplexDisabled() == false) {
-			myds->return_MySQL_Connection_To_Pool();
+		MySQL_Backend* _mybe = find_backend(warning_in_hg);
+		if (_mybe) {
+			MySQL_Data_Stream* myds = _mybe->server_myds;
+			if (myds && myds->myconn) {
+				myds->myconn->warning_count = 0;
+				myds->myconn->set_status(false, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
+				if ((myds->myconn->reusable == true) && myds->myconn->IsActiveTransaction() == false && myds->myconn->MultiplexDisabled() == false) {
+					myds->return_MySQL_Connection_To_Pool();
+				}
+			}
 		}
 		warning_in_hg = -1;
 	}

lib/mysql_connection.cpp

@@ -1565,6 +1565,12 @@ MDB_ASYNC_ST MySQL_Connection::handler(short event) {
 				NEXT_IMMEDIATE(ASYNC_QUERY_END);
 			} else {
 				// since 'add_eof' utilizes 'warning_count,' we are setting the 'warning_count' here
+
+				// Note: There is a possibility of obtaining inaccurate warning_count and server_status at this point
+				// if the backend server has CLIENT_DEPRECATE_EOF enabled, and the client does not support CLIENT_DEPRECATE_EOF,
+				// especially when the query generates a warning. This information will be included in the intermediate EOF packet. 
+				// Correct information becomes available only after fetching all rows,
+				// and the warning_count and status flag details are extracted from the final OK packet.
 				update_warning_count_from_connection();
 				if (myds->sess->mirror==false) {
 					if (MyRS_reuse == NULL) {
@@ -1671,7 +1677,7 @@ MDB_ASYNC_ST MySQL_Connection::handler(short event) {
 					// since 'add_eof' utilizes 'warning_count,' we are setting the 'warning_count' here
 					update_warning_count_from_connection();
 					// we reach here if there was no error
-					MyRS->add_eof();
+					MyRS->add_eof(query.length == 13 && strncasecmp(query.ptr, "SHOW WARNINGS", 13) == 0);
 					NEXT_IMMEDIATE(ASYNC_QUERY_END);
 				}
 			}
@@ -2615,7 +2621,8 @@ void MySQL_Connection::ProcessQueryAndSetStatusFlags(char *query_digest_text) {
 		if (warning_count > 0) {
 			// 'warning_in_hg' will be used if the next query is 'SHOW WARNINGS' or
 			// 'SHOW COUNT(*) WARNINGS'
-			myds->sess->warning_in_hg = myds->sess->current_hostgroup;
+			if (myds && myds->sess)
+				myds->sess->warning_in_hg = myds->sess->current_hostgroup;
 			// enabling multiplexing
 			set_status(true, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
 		}
@@ -2627,7 +2634,8 @@ void MySQL_Connection::ProcessQueryAndSetStatusFlags(char *query_digest_text) {
 		// on backend.
 		if (!((dig_len == 22 && strncasecmp(dig, "SHOW COUNT(*) WARNINGS", 22) == 0) ||
 			(dig_len == 13 && strncasecmp(dig, "SHOW WARNINGS", 13) == 0))) {
-			myds->sess->warning_in_hg = -1;
+			if (myds && myds->sess)
+				myds->sess->warning_in_hg = -1;
 			warning_count = 0;
 			// disabling multiplexing
 			set_status(false, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);