.

wcfs/δbtail.go

@@ -379,8 +379,10 @@ func (δBtail *ΔBtail) treediff(ctx context.Context, root zodb.Oid, δZT SetOid
 	return δT, nil
 }
 
-// diffT computes difference in between two revisions of substree.
-// δZTC is connected set of objects covering δZT (objects changed in this tree)
+// diffT computes difference in between two revisions of a tree's substree.
+//
+// a, b point to top of the subtree @old and @new revisions.
+// δZTC is connected set of objects covering δZT (objects changed in this tree in old..new).
 func diffT(ctx context.Context, a, b *Tree, δZTC SetOid) (δ map[Key]Value, err error) {
 	defer xerr.Contextf(&err, "diffT %s", a.POid())
 	if a.POid() != b.POid() {