.

wcfs/internal/xbtree/δbtail.go

@@ -586,7 +586,10 @@ func (δTtail *_ΔTtail) __rebuild(root zodb.Oid, δBtail *ΔBtail, releaseLock
 
 	// krebuildJobs += ktrackNew
 	for _, r := range ktrackNew.AllRanges() {
-		// XXX assert !krebuildJobs.IntersectsRange(e.KeyRange)
+		if δTtail.krebuildJobs.IntersectsRange(r) {
+			panicf("BUG: rebuild: krebuildJobs ^ ktrackNew != ø:\nkrebuildJobs: %s\nktrackNew: %s",
+			       δTtail.krebuildJobs, ktrackNew)
+		}
 		δTtail.krebuildJobs.SetRange(r, job)
 	}
 	delete(δBtail.trackNewRoots, root)