Cleaning up scene - IMRender Result error (bke.lib_id_delete)

[marciska]

Describe the issue

After rendering a scene, and then using the clean_up() function, an error is issued:

ERROR (bke.lib_id_delete): source/blender/blenkernel/intern/lib_id_delete.c:345 id_delete: Deleting IMRender Result which still has 1 users (including 0 'extra' shallow users)

Further, (maybe unrelated), but if ignoring this message and continuing to render the next scene, then at the time when the frames are written to disk this error is issued at the coco writer (bproc.writer.write_coco_annotations()):

Warning! Detected output entries with duplicate keys and paths

Minimal code example

import blenderproc as bproc
bproc.init()

bproc.object.create_primitive('CUBE')
bproc.camera.add_camera_pose(bproc.math.build_transformation_mat((0,-2,0), (1.57,0,0)))
frames = bproc.renderer.render()

# bproc.writer.write_coco_annotations(...)

bproc.clean_up() # error occurs here

# doing some other rendering ...

Files required to run the code

No response

Expected behavior

No error

BlenderProc version

v2.6.1

More information

Seems to appear when (inside the clean_up function) the image render result is removed. I suppose it is deleted too early, and there is some kind of dependency on another object that should get first deleted?

data_structure = getattr(bpy.data, 'images')
data_structure.remove(data_structure[0],do_unlink=True) # error appears here

[cornerfarmer]

Hey @marciska, thanks for your bug report and the minimal code example. I could reproduce the error, however it is not clear to me which other object still depends on the render result. Despite the error message, the code execution still continues and the render result image also gets deleted. So for now it seems one can ignore this error message, but I will keep an eye on it.