Maya: Fix update reference without reference node showing wrong error message

[BigRoy]

Note

PR moved from ynput/ayon-core#465

Changelog Description

Raise LoadError instead of assert on no reference node found on Maya reference update

Additional info

Fixes #9

Note: This now currently shows no dialog.

Testing notes:

Easiest way to get into a 'broken' state for the ReferenceLoader:

1. Load a Maya reference
2. In outliner enable > Display > Ignore "Hidden in outliner"
3. In AVALON_CONTAINERS add an object into the reference container (just so that maya does not auto-delete it in next step)
4. On the loaded maya reference remove the reference (via Maya itself, not via AYON tools)
5. Container object set should still exist, but no reference node
6. Via Ayon > Manage.. try to set the version of the container - it will fail.

[LiborBatek]

I have followed the steps....as said, no any error raised via UI just the following log in the script editor:

# Traceback (most recent call last):
#   File "C:\Work\REPO\ayon-core\client\ayon_core\tools\sceneinventory\view.py", line 366, in <lambda>
#     lambda: self._show_version_dialog(item_ids, active_repre_id)
#   File "C:\Work\REPO\ayon-core\client\ayon_core\tools\sceneinventory\view.py", line 843, in _show_version_dialog
#     self._update_containers_to_version(
#   File "C:\Work\REPO\ayon-core\client\ayon_core\tools\sceneinventory\view.py", line 1032, in _update_containers_to_version
#     self._update_containers(item_ids, versions)
#   File "C:\Work\REPO\ayon-core\client\ayon_core\tools\sceneinventory\view.py", line 1007, in _update_containers
#     update_container(container, item_version)
#   File "C:\Work\REPO\ayon-core\client\ayon_core\pipeline\load\utils.py", line 539, in update_container
#     return Loader().update(container, context)
#   File "c:\Work\REPO\ayon-maya\client\ayon_maya\plugins\load\load_reference.py", line 256, in update
#     super(ReferenceLoader, self).update(container, context)
#   File "c:\Work\REPO\ayon-maya\client\ayon_maya\api\plugin.py", line 808, in update
#     raise LoadError("No reference node found in container")
# ayon_core.pipeline.load.utils.LoadError: No reference node found in container

[BigRoy]

Thanks @LiborBatek - the lack of UI dialog on the error is indeed an issue, but a separate one from reporting the correct error starting here. The UI issue would need changes in ayon-core. After this will be merged I can make a follow-up issue on Ayon core.

[iLLiCiTiT]

Handling of errors in scene inventory is a different beast.

[LiborBatek]

@BigRoy thx for clarification, as I wasnt sure if thats all needed for Approval review, call it my lack of knowledge :)

[LiborBatek]

Works ok.