Some missing mapping somehow happens which prevent the loader from finishing.
I recall seeing that this part is not covered in the loader so we are missing the right test around this to fix it.
```
ERROR:swh.loader.mercurial.LoaderFromDisk:Loading failure, updating to `failed` status
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/swh/loader/core/loader.py", line 339, in load
self.store_data()
File "/usr/lib/python3/dist-packages/swh/loader/mercurial/from_disk.py", line 452, in store_data
target = self.get_revision_id_from_hg_nodeid(node_id)
File "/usr/lib/python3/dist-packages/swh/loader/mercurial/from_disk.py", line 526, in get_revision_id_from_hg_nodeid
assert len(from_storage) == 1, msg % (hg_nodeid.hex(), len(from_storage))
AssertionError: Expected 1 match from storage for hg node '64353138623066626536626164656565336638303062663664343638313639343833643838626338', got 0
{'status': 'failed'}
```
[1] P1169