.

wcfs/δbtail.go

@@ -273,9 +273,10 @@ type nodeTrack struct {
 //
 //     Only complete result of applying all
 //
+//         - xfixup(-1, δnchildNonLeafs)
 //         - δ.Del,
 //         - δ.Add, and
-//         - fixup(δnchildNonLeafs)
+//         - xfixup(+1, δnchildNonLeafs)
 //
 //     produce correctly PP-connected set.
 //
@@ -841,7 +842,7 @@ func (tidx trackIndex) AddPath(path []zodb.Oid) {
 	}
 }
 
-// rebuild rebuilds ΔBtail taking trackNew requests into account. XXX
+// rebuild rebuilds ΔBtail taking trackNew requests into account.
 // XXX place
 func (δBtail *ΔBtail) rebuild() (err error) {
 	defer xerr.Context(&err, "ΔBtail rebuild")
@@ -850,6 +851,10 @@ func (δBtail *ΔBtail) rebuild() (err error) {
 	trackNew := δBtail.trackNew
 	δBtail.trackNew = trackIndex{}
 
+	if len(trackNew) == 0 {
+		return
+	}
+
 	// go backwards and merge vδT <- treediff(lo..hi/trackNew)
 	vδZ := δBtail.δZtail.Data()
 	for i := len(vδZ)-1; i>=0; i-- {
@@ -936,7 +941,6 @@ func (δBtail *ΔBtail) rebuild() (err error) {
 
 			// XXX update .KVAtTail, .lastRevOf
 		}
-
 	}
 
 	// merge trackNew into .trackIdx