.

wcfs/δbtail.go

@@ -947,7 +947,8 @@ func (δBtail *ΔBtail) rebuild() (err error) {
 		}
 	}
 
-	// trackNew was adjusted to correspond to @tail. Map it back to @head and merge to .trackIdx
+	// trackNew was adjusted to correspond to @tail potentially growing its key coverage.
+	// Remap it back to @head and merge to .trackIdx
 	for _, δtrack := range vδtrack {
 		δtrack.Reverse() // we saved it as lo<-hi; now we go lo->hi
 		trackNew.ApplyΔ(δtrack)