openDocument of Assembly3 document with freecadcmd results in Aborted

[khimaros]

FreeCAD version: 0.20.2
A3 Version: 0.12.0

this happens even with an empty assembly: empty-assembly.FCStd.gz

i'm trying to set up CI/CD for my FreeCAD workflow. all of my parts individually can be opened and exported in headless mode using freecadcmd and a bit of python code.

however, when trying to open an Assembly3 document, freecadcmd aborts prematurely without any explanation as to why.

reproducible consistently with this bit of code:

#!/usr/bin/env freecadcmd

import sys

import FreeCAD

path, dest = sys.argv[1:]

print('### opening document', path)

FreeCAD.openDocument(path)

the output is as follows:

FreeCAD 0.20.2, Libs: 0.20.2R
(c) Juergen Riegel, Werner Mayer, Yorik van Havre and others 2001-2022
FreeCAD is free and open-source software licensed under the terms of LGPL2+ license.
FreeCAD wouldn't be possible without FreeCAD community.
  #####                 ####  ###   ####  
  #                    #      # #   #   # 
  #     ##  #### ####  #     #   #  #   # 
  ####  # # #  # #  #  #     #####  #   # 
  #     #   #### ####  #    #     # #   # 
  #     #   #    #     #    #     # #   #  ##  ##  ##
  #     #   #### ####   ### #     # ####   ##  ##  ##

### opening document cad/atom/atom-assembly.FCStd
Aborted

[khimaros]

there is some helpful discussion and hint provided in the referenced FreeCAD issue: FreeCAD/FreeCAD#10526