For "weird" objects, alongside the rest of the row.
- add a new raw_manifest field to Directory and Revision objects (and Release, for future-proofing), with type Optional[bytes]. it should contain the type and size (ie. the complete git header)
- add a check method to model objects; should check the id matches (self.compute_hash() == self.id), but also that if raw_manifest is not None, then then it must differ from the manifest we would compute (ie. there shouldn't be a useless value in raw_manifest)
- Add a column in postgres, defaults to NULL and write it
- Monitor the number of objects with a non-NULL raw_manifest, and warn if it raises too fast (it probably means there is a bug in a loader) -> swh-counters
- Figure a way to report issues from directly from the git loader? (eg. make the git-loader raise an issue in sentry if too many objects in the same repo have a raw_manifest)
Make the vault use it when available, somewhere after 3