.

wcfs/δbtail.go

@@ -857,6 +857,7 @@ func (δBtail *ΔBtail) rebuild() (err error) {
 
 	// go backwards and merge vδT <- treediff(lo..hi/trackNew)
 	vδZ := δBtail.δZtail.Data()
+	vδtrack := []*δtrackIndex{}
 	for i := len(vδZ)-1; i>=0; i-- {
 		δZ := vδZ[i]
 
@@ -904,6 +905,7 @@ func (δBtail *ΔBtail) rebuild() (err error) {
 			tracef("-> root<%s>  δkv*: %v  δtrack*: %v\n", root, δT, δtrack)
 
 			trackNew.ApplyΔ(δtrack)
+			vδtrack = append([]*δtrackIndex{δtrack}, vδtrack...)
 
 			if len(δT) == 0 { // an object might be resaved without change
 				continue
@@ -945,11 +947,11 @@ func (δBtail *ΔBtail) rebuild() (err error) {
 		}
 	}
 
-	// merge trackNew into .trackIdx
-	// FIXME here trackNew was adjusted to correspond to @tail
-	// FIXME -> we have to map it back to correspond to @head before merge
-	//
-	// TODO -> remember δtracks from treediff; reverse them and apply them back in reverse order.
+	// trackNew was adjusted to correspond to @tail. Map 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)
+	}
 	δBtail.trackIdx.UnionInplace(trackNew)
 
 	return nil