Vcs.RefsSourceinclude module type of Volgo.Vcs.Refs
with type t := t
and module Line := Volgo.Vcs.Refs.LineTo lookup the revision of references (branch, tag, etc.), it is usually quite cheap to get all refs using Vcs.refs, turn the result into a map with this function, and use the map for the lookups rather than trying to run one git command per lookup. You may also use Vcs.Graph.find_ref if you build the complete graph with Vcs.graph.