Merge branch 'ps/object-collision-check'

CI jobs gave sporadic failures, which turns out that that the object finalization code was giving an error when it did not have to. * ps/object-collision-check: object-file: retry linking file into place when occluding file vanishes object-file: don't special-case missing source file in collision check object-file: rename variables in `check_collision()` object-file: fix race in object collision check