resource leak in agw.aui.AuiManager

Oren1 · March 6, 2012, 2:11pm

I’m having a memory leakage problem using agw.aui.AuiManager.

I’ve created a stripped down sample that shows the leak - listed below.
I’m creating a panel and destroying it repeatedly. Memory usage grows and after a short while the application fires he following assertion error:

wx._core.PyAssertionError: C++ assertion “IsOk()” failed at …\src\common\image.cpp(1506) in wxIm
age::Replace(): invalid image

I’m calling UnInit() to release the aui manager as described in the doc.

When removing the creation the AuiManager (and the UnInit() ) there is no leakage.

I’m using wx ver:2.9.3.1, but I’m suspecting it happens in ver 2.8.1 as well.

I would appreciate any thought on this.

Thanks,
Oren

import wx
from wx.lib.agw import aui

class MyPanel(wx.Panel):
def init(self, parent):
wx.Panel.init(self, parent)
self._aui_mgr = aui.AuiManager()

def Destroy(self):
    self._aui_mgr.UnInit()
    wx.Panel.Destroy(self)

class MainWindow(wx.Frame):
def init(self):
wx.Frame.init(self, parent=None)
self.Show(True)

    self.Bind(wx.EVT_TIMER, self._on_timer)
    self._timer = wx.Timer(self)
    self._timer.Start(100)

def _on_timer(self, event):
    new_panel = MyPanel(self)
    new_panel.Destroy()

def main():
app = wx.App()
mw = MainWindow()
app.MainLoop()

if name == ‘main’:
main()

Robin · March 6, 2012, 6:29pm

What happens if you add a self._aui_mgr.Destroy() after the UnInit?

···

On 3/6/12 6:11 AM, Oren Gampel wrote:

I'm having a memory leakage problem using agw.aui.AuiManager.

I've created a stripped down sample that shows the leak - listed below.
I'm creating a panel and destroying it repeatedly. Memory usage grows
and after a short while the application fires he following assertion error:
wx._core.PyAssertionError: C++ assertion "IsOk()" failed at
..\..\src\common\image.cpp(1506) in wxIm
age::Replace(): invalid image

I'm calling UnInit() to release the aui manager as described in the doc.

When removing the creation the AuiManager (and the UnInit() ) there is
no leakage.

I'm using wx ver:2.9.3.1, but I'm suspecting it happens in ver 2.8.1 as
well.

I would appreciate any thought on this.

--
Robin Dunn
Software Craftsman

Andrea_Gavana · March 6, 2012, 7:43pm

This works for me here on Windows 7, wxPython 2.9.3. However, it seems
a bit odd: why do we have to explicitly Destroy() a wx.EvtHandler
(which is what AuiManager is)? And, more important, should I put that
line in the UnInit method of AuiManager directly in the SVN version?

Andrea.

"Imagination Is The Only Weapon In The War Against Reality."
http://xoomer.alice.it/infinity77/

···

On 6 March 2012 19:29, Robin Dunn wrote:

On 3/6/12 6:11 AM, Oren Gampel wrote:

I'm having a memory leakage problem using agw.aui.AuiManager.

I've created a stripped down sample that shows the leak - listed below.
I'm creating a panel and destroying it repeatedly. Memory usage grows
and after a short while the application fires he following assertion
error:
wx._core.PyAssertionError: C++ assertion "IsOk()" failed at
..\..\src\common\image.cpp(1506) in wxIm
age::Replace(): invalid image

I'm calling UnInit() to release the aui manager as described in the doc.

When removing the creation the AuiManager (and the UnInit() ) there is
no leakage.

I'm using wx ver:2.9.3.1, but I'm suspecting it happens in ver 2.8.1 as
well.

I would appreciate any thought on this.

What happens if you add a self._aui_mgr.Destroy() after the UnInit?

Robin · March 6, 2012, 11:08pm

I'm having a memory leakage problem using agw.aui.AuiManager.

I've created a stripped down sample that shows the leak - listed below.
I'm creating a panel and destroying it repeatedly. Memory usage grows
and after a short while the application fires he following assertion
error:
wx._core.PyAssertionError: C++ assertion "IsOk()" failed at
..\..\src\common\image.cpp(1506) in wxIm
age::Replace(): invalid image

I'm calling UnInit() to release the aui manager as described in the doc.

When removing the creation the AuiManager (and the UnInit() ) there is
no leakage.

I'm using wx ver:2.9.3.1, but I'm suspecting it happens in ver 2.8.1 as
well.

I would appreciate any thought on this.

What happens if you add a self._aui_mgr.Destroy() after the UnInit?

This works for me here on Windows 7, wxPython 2.9.3. However, it seems
a bit odd: why do we have to explicitly Destroy() a wx.EvtHandler
(which is what AuiManager is)?

Think of it as if it was a wx.Window with no parent. Normally a wx.Window is destroyed by the parent when the parent is destroyed, (unless you want to do it yourself before that point in time so you call Destroy to get rid of it). And normally top-level windows will destroy themselves when they are closed and that also destroys all the children recursively.

Now if it was possible for a wx.Window to have no parent then there would be nothing that "owns" it on the C++ side that will automatically destroy it when the owner is done with it. Theoretically we could have the Python proxy own the C++ object so it will automatically be destroyed when the proxy object is destroyed, however just like wx.Window the wx.EvtHandler C++ object holds an extra reference to the Python proxy object for use with OOR and event dispatching. So in other words there is a Python reference cycle that can't be broken by the GC, only by causing the C++ object to delete itself which is what Destroy() does.

Another way to look at it is that this is simply the same pattern used by wx.Dialogs, wx.TaskbarIcons and menus used with PopupMenu. You need to explicitly destroy them when done with them.

And, more important, should I put that
line in the UnInit method of AuiManager directly in the SVN version?

If it is fairly certain that nothing else will be done with the AuiManager after UnInit is called then it should be safe to have it destroy itself there.

···

On 3/6/12 11:43 AM, Andrea Gavana wrote:

On 6 March 2012 19:29, Robin Dunn wrote:

On 3/6/12 6:11 AM, Oren Gampel wrote:

--
Robin Dunn
Software Craftsman

Oren · March 7, 2012, 1:17pm

Thanks a lot for you responses!

The original problem rises on win XP and also Linux (checked Ubuntu and Kubuntu) in version 2.9. and 2.8.

Adding the suggested self._aui_mgr.Destroy() does resolve the problem and the test program stops leaking.

However, while creating the stripped down version, I’ve omitted the call

    self._aui_mgr.SetManagedWindow(self)

after creating the aui manager. When this is set I can no longer Destroy() the manager, but there is also no leak. I’ve now added UnInint() to the Destroy of all my AuiManger() and Indeed most of the leaks are gone.

However:

Andrea, please note that AuiNotebook Doesn’t UnInit()

The following code shows my current leak. I use the notebook’s GetAuiManager() and UnInit() it myself. This works well, unless I add a page. In this case there is a leak, even if I explicitly DeletePage() it.

Again, thank you for your input!

class MyNotebook(aui.AuiNotebook):
def init(self, p):
aui.AuiNotebook.init(self, p, -1)
self._page = wx.Panel(self, -1)
self.AddPage(self._page, ‘?’)

def Destroy(self):
    found, idx = self.FindTab(self._page)
    if found:
        self.DeletePage(idx)

    self.GetAuiManager().UnInit() #workaround the missing UnInit()
    aui.AuiNotebook.Destroy(self)

class MainWindow(wx.Frame):
def init(self):
wx.Frame.init(self, parent=None)
self.Show(True)

    self.Bind(wx.EVT_TIMER, self._on_timer)
    self._timer = wx.Timer(self)
    self._timer.Start(100)

def _on_timer(self, event):
    new_panel = MyNotebook(self)
    new_panel.Destroy()

def main():
app = wx.App()
mw = MainWindow()
app.MainLoop()

if name == ‘main’:
main()

···