Why do interface implementations based on TComponent leak memory?

Question

This Delphi code will show a memory leak for an instance of TMyImplementation:

program LeakTest;

uses
  Classes;

type
  MyInterface = interface
  end;

  TMyIm         


        

Answer 1

Differences in implementation

• TComponent._Release does not free your instance.
• TInterfacedObject._Release does free your instance.

Perhaps someone can chime in but my take on this is that TComponent is not meant to be used as a reference counted object the way we normally use interfaces.

Implementation of TComponent._Release

function TComponent._Release: Integer;
begin
  if FVCLComObject = nil then
    Result := -1   // -1 indicates no reference counting is taking place
  else
    Result := IVCLComObject(FVCLComObject)._Release;
end;