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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for December 15th, 2020

Alternatives to UUID/GUID as database keys

Posted by jpluimers on 2020/12/15

For my link archive:

–jeroen

Posted in Database Development, Development, PostgreSQL, Software Development | Leave a Comment »

I really wish people reporting bugs provide more factual details, especially when asked for

Posted by jpluimers on 2020/12/15

Basically the below thread goes like this: [WayBack] GExperts / Bugs / #92 Grep cannot handle UTF-16 and UTF-32 pas files

  1. There is a bug in UTF-16 and UTF-32 handling in your tool when running under AAA, but  not when running your tool under BBB; these files fail: xxx.txt  and yyy.txt
  2. Which version of our tool did you run under AAA and which version of our tool did you run under BBB
  3. It fails with your tool when running under AAA , but succeeds under BBB
  4. Repeat at step 2 until you fall asleep.

Part of the [WayBack] Short, Self Contained, Correct Example are indeed in it, but without more details it is hard to reproduce.

So without the reporter providing those details, nobody, especially not on open source projects, is going to fix it just on that bug report.

Via: [WayBack] It’s time for a gift to all Delphi developers, a new Release of GExperts. Happy Holidays! (But do spend some time with your family rather than testing G… – Thomas Mueller (dummzeuch) – Google+

Which highlights another conceptual problem from the same bug reporter: expecting a new version to have a regression of all open bugs against the new version.

That’s not how the world works, if it has ever worked that way. If your issue is not mentioned in any release notes, then assume nothing happened. If you want to bump it up, then provide more details.

–jeroen

Posted in Conference Topics, Conferences, Development, Event, How to report bugs, Issue/Bug tracking, Software Development | Leave a Comment »

In Delphi, avoid having a TComponent descendant implement interfaces, unless you are prepared to handle your refcounting

Posted by jpluimers on 2020/12/15

Every now and then I see code, where a class descending from TComponent implements some interfaces, only interface references are used to the instances, and the expected behaviour is that the instances will free themselves when all the references went out of scope.

Bummer: TComponent by default is not reference counted.

It is when you assign VCLComObject an IVCLComObject which is hell to implement (Delphi provides two of them: TVCLAutoObject and TActiveFormControl. They sound heavey, and are).

Do not go that way. If you need some form of ownership in a class implementing an interface, then descend the class from TInterfacedObject, and add a field of TComponent that is the owner of things that need to be freed later on. In the destructor, free that field.

Something like this:

unit InterfacedObjectWithRootUnit;

interface

type
   TInterfacedObjectWithRoot = class(TInterfacedObject)
   strict private
      FRoot: TComponent;
      function GetRoot: TComponent;
   strict protected
      property Root: TComponent read GetRoot;
   public
      destructor Destroy; override;
   end;

implementation

destructor TInterfacedObjectWithRoot.Destroy;
begin
  if Assigned(FRoot) then
  begin
    FRoot.Free();
    FRoot := nil;
  end;
  inherited Destroy();
end;

function TInterfacedObjectWithRoot.GetRoot: TComponent;
begin
  if FRoot = nil then
    FRoot := TComponent.Create(nil);
  Result := FRoot;
end;

end.

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | Leave a Comment »

 
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