Blender Git Commit Log

Fix T66154: viewlayer hide/exclude settings getting lost for linked collections

The problem was that the object and collection pointers in Base and
LayerCollection would get lost of file read. Normally such ID pointers would
be resolved by pointing to an ID_ID placeholder which has the datablock name,
and then replacing it will the real datablock. However ID_ID is only written
for directly linked datablocks.

This adds the concept of an indirectly linked datablock with a weak reference
to it. For this we write an ID_ID_WEAK_REF code, which is a reference that
will only be resolved if the datablock was read for another reason.

Differential Revision: https://developer.blender.org/D4416