[nrr]

Fossil (https://fossil-scm.org) is actually a proper grow-only set from what I can tell: merge conflicts upon synchronization are encoded in the DAG as forks of the history at the conflicting points in time. If no action is taken after a fork, all clones will eventually see the exact same view of the history.

The tooling will normally bail with a "would fork" message if a `fossil update` (and, hence, local resolution of those conflicts) wasn't undertaken before pushing, but this is not at all necessary to preserve useful operation.