TDataSet.InitFieldDefsFromfields Bug
lazarus / 63-Database

----------------------------------------------------------------------
derek.john.evans · 2016-08-16 23:38

Just a post to see if this is a bug:

I came across what looks like a bug in
TDataSet.InitFieldDefsFromfields (dataset.inc)

PROBLEM: TField and TFieldDef both have the properties Required &
DataType.

The code is using two "with/do" statements (which needs to be fixed).
The inner "with/do" is the TFieldDef (LINE:13), which refers to
Required/DataType expecting to read from the outer TField (LINE:9).
But, it just reads from itself.

Therefore, TField properties arn't copied to the TFieldDef's

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TDataSet.InitFieldDefsFromfields;var i : integer; begin  if
FieldDefs.count = 0 then    begin    FieldDefs.BeginUpdate;    try   
 for i := 0 to Fields.Count-1 do with fields[i] do        if not
(FieldKind in [fkCalculated,fkLookup]) then // Do not add fielddefs
for calculated/lookup fields.          begin          FFieldDef:=Field
Defs.FieldDefClass.Create(FieldDefs,FieldName,DataType,Size,Required,F
ieldDefs.Count+1);          with FFieldDef do            begin       
   if Required then Attributes := attributes + [faRequired];         
 if ReadOnly then Attributes := attributes + [faReadOnly];           
if DataType = ftBCD then precision := (fields[i] as
TBCDField).Precision            else if DataType = ftFMTBcd then
precision := (fields[i] as TFMTBCDField).Precision;            end;  
      end;    finally      FieldDefs.EndUpdate;      end;    end;end;

----------------------------------------------------------------------
LacaK · 2016-10-15 16:39

Edited:
Although it seems strange, there is no bug 
Because:
FFieldDef:=FieldDefs.FieldDefClass.Create(FieldDefs,FieldName,DataType
,Size,Required,FieldDefs.Count+1);

here are passed DataType and Required to newly created FFieldDef
object, so after this statement FFieldDef and fields have same values
for DataType and Required