.

wcfs/internal/zdata/δftail.go

@@ -554,7 +554,7 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 			if δfTail.Rev == tail {
 				return δfTail
 			}
-			if !(tail <= δfTail.Rev) {
+			if !(tail < δfTail.Rev) {
 				panic("tail not ↓")
 			}
 		}
@@ -581,7 +581,7 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 	// vδE[ie]   is next epoch
 	// vδE[ie-1] is epoch that covers hi
 
-	// loop through all epochs till lo
+	// loop through all epochs from hi till lo
 	for lastEpoch := false; !lastEpoch ; {
 		// current epoch
 		var epoch zodb.Tid
@@ -613,7 +613,6 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 					Zinblk[zblk] = inblk.Clone()
 				}
 			}
-			// XXX ZinblkAt
 		} else {
 			δE := vδE[ie+1]
 			root = δE.oldRoot
@@ -633,7 +632,7 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 		}
 
 		// merge vδZ and vδT of current epoch
-		for ((iz >= 0 && vδZ[iz].Rev > epoch) || it >= 0) {	// XXX  ->  `δZ.Rev > epoch`
+		for ((iz >= 0 && vδZ[iz].Rev > epoch) || it >= 0) {
 			// δZ that is covered by current Zinblk
 			// -> update δf
 			if iz >= 0 && vδZ[iz].Rev > epoch {