TCSVDataset FieldDefs defaults to ftString, 255 when reading from CSV-file

[Vodnik]

I can't succeed defining  CSVDataset1.FieldDefs in case when dataset is linked to existing CSV-file.
When dataset is opened, FieldDefs are overwritten with DataType=ftString and Size=255.
Is it a bug, an idea or I'm doing something wrong?
Test project  attached.
First run - no CSV file - FieldDefs are OK - CSV file is created accordingly.
Second run - CSV file exist - FieldDefs are default - record appended to CSV in wrong format.

Code: Pascal  [Select][+][-]

1. program TestCSVDS;
2.  
3. uses csvdataset, sysutils, db;
4.  
5. var  CSVDataSet1: TCSVDataSet;
6.      CSVFileName: String = 'data.csv';
7.      I: Integer;
8.  
9. begin
10.   CSVDataset1:=TCSVDataset.Create(nil);
11.   try
12.     CSVFileName:=ExtractFilePath(Paramstr(0)) + CSVFileName;
13.     CSVDataset1.FileName:=CSVFileName;
14.     CSVDataset1.CSVOptions.FirstLineAsFieldNames:=False;
15.     CSVDataset1.FieldDefs.Add('Date and time', ftDateTime);
16.     CSVDataset1.FieldDefs.Add('Duration', ftTime);
17.     CSVDataset1.FieldDefs.Add('Event', ftString,40);
18.      if FileExists(CSVFileName) then begin
19.        Writeln('File '+CSVFileName+' exist');
20.      end else begin
21.        CSVDataset1.CreateDataset;
22.        Writeln('File '+CSVFileName+' not exist');
23.      end;
24.     CSVDataset1.Open;
25.     CSVDataset1.AppendRecord([EncodeDate(2023,03,03),EncodeTime(13,08,01,000),'Oleg']);
26.     for I:= 0 to csvdataset1.FieldDefs.Count-1 do begin
27.       Writeln('Record: ',I,', data type: ',csvdataset1.FieldDefs.Items[I].DataType,', data size: ', csvdataset1.FieldDefs.Items[I].Size);
28.     end;
29.     CSVDataset1.Close;
30.     CSVDataset1.Free;
31.     Readln;
32.   except
33.  
34.   end;
35. end.
36.  

File data.csv after 2 runs:

Code: Pascal  [Select][+][-]

1. 03.03.2023,13:08:01,Oleg
2. 44988,"0,547233796296296",Oleg

[tatamata]

Thank you for asking this question, I have noticed and wondering about the same thing while working on new ZMSQL version. Curious to see answers.