TPyDelphiWrapper - memory leaks

[iqrf 3]

Hi,

i have this code

TColumn = class(TPersistent)
private
  FHeaderName: String;
  FVisible: Boolean;
  FWidth: Integer;
  FPosition: Integer;
  procedure SetHeaderName(const Value: String);
  procedure SetVisible(const Value: Boolean);
  procedure SetWidth(const Value: Integer);
  procedure SetPosition(const Value: Integer);
public
  property HeaderName: String read FHeaderName write SetHeaderName;
  property Visible: Boolean read FVisible write SetVisible;
  property Width: Integer read FWidth write SetWidth;
  property Position: Integer read FPosition write SetPosition;
end;

TColumnWrapper = class(TPyClassWrapper<TColumn>)
  constructor CreateWith(APythonType: TPythonType; args, kwds: PPyObject); override;
end;

TTerminalLogSettings = class(TPersistent)
private
  fColumn: TDictionary<String,TColumn>;
  function GetAutoScroll: Boolean;
  function GetSeparatorH: Boolean;
  function GetSeparatorV: Boolean;
  function GetViewData: Boolean;
  procedure SetAutoScroll(const Value: Boolean);
  procedure SetSeparatorH(const Value: Boolean);
  procedure SetSeparatorV(const Value: Boolean);
  procedure SetViewData(const Value: Boolean);
public
  constructor Create;
  destructor Destroy; override;
  property AutoScroll: Boolean read GetAutoScroll write SetAutoScroll;
  property SeparatorH: Boolean read GetSeparatorH write SetSeparatorH;
  property SeparatorV: Boolean read GetSeparatorV write SetSeparatorV;
  property ViewData: Boolean read GetViewData write SetViewData;
  property Column: TDictionary<String, TColumn> read fColumn write fColumn;
end;

...
FPythonModule_TerminalLog := TPythonModule.Create(nil);
FPythonModule_TerminalLog.Name := 'FPythonModule_TerminalLog';
FPythonModule_TerminalLog.Engine := FEngine;
FPythonModule_TerminalLog.ModuleName := 'terminal_log';
FPythonModule_TerminalLog.OnInitialization := OnInitialization_TerminalLog;
FPythonModule_TerminalLog.OnAfterInitialization := OnAfterInitialization_TerminalLog;
...
FPythonVersion.AssignTo(FEngine);
FEngine.LoadDll;
...  
terminalLogSettings := TTerminalLogSettings.Create;
pTerminalLogSettings := FPythonWrapper.Wrap(terminalLogSettings, soOwned);
FPythonModule_TerminalLog.SetVar( 'settings', pTerminalLogSettings);
FEngine.Py_DecRef(pTerminalLogSettings);
 
FPythonWrapper.RegisterDelphiWrapper(TColumnWrapper).Initialize;
FPythonWrapper.RegisterDelphiWrapper(TPyClassWrapper<TDictionary<string, TColumn>>).Initialize;
...

if used in this way in the script, then after the script finishes I correctly call the TTerminalLogSettings destructor and free the memory

...
iqrfide.terminal_log.settings.autoScroll = True
...

settings_object = iqrfide.terminal_log.settings
setattr(settings_object, 'autoScroll', True)
...

If the script is interrupted using exit(), the destructor is not called and the memory is not freed. Any explanation?

...
iqrfide.terminal_log.settings.autoScroll = True
...

settings_object = iqrfide.terminal_log.settings
setattr(settings_object, 'autoScroll', True)

exit()
...

Putting settings_object = None before exit solves the problem.

[pyscripter 583]

The exit() function raises a SystemExit exception and if it is not handled it shuts down python.  Don't use it in P4D scripts.

[iqrf 3]

Hi, not using exit() is not the solution for me. Users use exit() when debugging a script.

If to ProcessSystemExit; i add Py_DecRef(errtraceback); so the memory leak problem will disappear. The destructor TTerminalLogSettings will already be called. I have no idea, but how is that possible.

procedure TPythonEngine.CheckError(ACatchStopEx : Boolean = False);
  procedure ProcessSystemExit;
  var
    errtype, errvalue, errtraceback: PPyObject;
    SErrValue: string;
  begin
    PyErr_Fetch(errtype, errvalue, errtraceback);
    Traceback.Refresh(errtraceback);
    SErrValue := PyObjectAsString(errvalue);
    Py_DecRef(errtraceback);      // workaround
    PyErr_Clear;
    raise EPySystemExit.CreateResFmt(@SPyExcSystemError, [SErrValue]);
  end;

 

[pyscripter 583]

@iqrfYou are absolutely right,  PyErr_Fetch returns new references and clears the error. The code in ProcessSystemExit has now been fixed.  Thanks!

Edited March 13 by pyscripter