server: Support flag 128 in execution of prepared statements (#36732)

close #36731

parser/mysql/const.go

@@ -600,3 +600,10 @@ const (
 	// Reference linking https://dev.mysql.com/doc/refman/5.7/en/partitioning-limitations.html.
 	PartitionCountLimit = 8192
 )
+
+// This is enum_cursor_type in MySQL
+const (
+	CursorTypeReadOnly = 1 << iota
+	CursorTypeForUpdate
+	CursorTypeScrollable
+)

server/conn_stmt.go

@@ -137,21 +137,18 @@ func (cc *clientConn) handleStmtExecute(ctx context.Context, data []byte) (err e
 
 	flag := data[pos]
 	pos++
-	// Please refer to https://dev.mysql.com/doc/internals/en/com-stmt-execute.html
+	// Please refer to https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_com_stmt_execute.html
 	// The client indicates that it wants to use cursor by setting this flag.
-	// 0x00 CURSOR_TYPE_NO_CURSOR
-	// 0x01 CURSOR_TYPE_READ_ONLY
-	// 0x02 CURSOR_TYPE_FOR_UPDATE
-	// 0x04 CURSOR_TYPE_SCROLLABLE
 	// Now we only support forward-only, read-only cursor.
-	var useCursor bool
-	switch flag {
-	case 0:
-		useCursor = false
-	case 1:
+	useCursor := false
+	if flag&mysql.CursorTypeReadOnly > 0 {
 		useCursor = true
-	default:
-		return mysql.NewErrf(mysql.ErrUnknown, "unsupported flag %d", nil, flag)
+	}
+	if flag&mysql.CursorTypeForUpdate > 0 {
+		return mysql.NewErrf(mysql.ErrUnknown, "unsupported flag: CursorTypeForUpdate", nil)
+	}
+	if flag&mysql.CursorTypeScrollable > 0 {
+		return mysql.NewErrf(mysql.ErrUnknown, "unsupported flag: CursorTypeScrollable", nil)
 	}
 
 	// skip iteration-count, always 1