Fail to properly unregister extension - extension object is still alive - Kit 106.3.0

[nils.fischer]

[Warning] [omni.ext._impl._internal] xxxxxx.combined.variants-1.0.0 → <class ‘xxxxxx.combined.variants.extension.CombinedVariantSetEditor’>: extension object is still alive, something holds a reference on it. References: [“[0]:type: <class ‘method’>, id: 1843184037248”]

Hi there, I’m banging my head against this error generated when unregistering an extension involving menu entries and a file picker window. Interestingly, some NVIDIA extensions such as omni.kit.variant.editor produce the exact same error upon unregistering. It would appear that I am missing some trick in on_shutdown when cleaning up. Any ideas?

[Richard3D]

Thanks for posting the question. I will ask one of kit devs to see if they can help.

[Richard3D]

This can be tricky to solve. Typically it’s something like:

• If you register a callback you need to deregister it
• If you create a ui you need to destroy it (recursively)

Can you take a look at this document and see if that helps?

[eric.craft.MH]

I know this is a little old, but I was battling this and the issue with the window not closing properly. I was able to find the answer digging into other tools and finding the best solution in the extension.py for omni.kit.window.commands. Solution below:

• Add MenuHelperExtensionFull and add to your Extension Class

from omni.kit.menu.utils import MenuHelperExtensionFull

class Extension(omni.ext.IExt, MenuHelperExtensionFull):

• in on_startup add self.menu_startup

def on_startup(self):
    self.menu_startup(create_window_fn=lambda:Window(WINDOW_NAME), window_name=WINDOW_NAME, menu_desc="Some Text", menu_group="Window")

• in on_shutdown call self.menu_shutdown

def on_shutdown(self):
    self.menu_shutdown()

MenuHelperExtensionFull is documented in the omni.kit.menu.utils docs.

Hope this helps others save time in the future.

[Richard3D]

Thanks Eric