Address comments, and actually check if the peers are being removed.

partitions.go

@@ -113,9 +113,9 @@ func (p *partitions) updateLocalPartitions(local map[int]bool) {
 	}
 }
 
-func (p *partitions) deDupe(nodes []string) []string {
+func dedupe(nodes []string) []string {
 	found := map[string]bool{}
-	dedupedNodes := make([]string, len(nodes))
+	dedupedNodes := make([]string, 0, len(nodes))
 	for _, node := range nodes {
 		if !found[node] {
 			found[node] = true
@@ -144,12 +144,22 @@ func (p *partitions) updateRemotePartitions(nodes []string) {
 		}
 	}
 
-	for partitionId, partition := range remote {
-		newPartition := make([]string, len(partition))
-		copy(newPartition, partition)
+	for partitionId, partition := range p.remote {
+		disappearedPeers := make([]string, len(partition))
 
-		unDedupedPartition := append(newPartition, p.disappeared[partitionId]...)
-		p.disappeared[partitionId] = p.deDupe(unDedupedPartition)
+		for _, oldPeer := range partition {
+			found := false
+			for _, newPeer := range remote[partitionId] {
+				if newPeer == oldPeer {
+					found = true
+				}
+			}
+			if !found {
+				disappearedPeers = append(disappearedPeers, oldPeer)
+			}
+		}
+
+		p.disappeared[partitionId] = dedupe(append(disappearedPeers, p.disappeared[partitionId]...))
 		if len(p.disappeared[partitionId]) >= 1024 {
 			p.disappeared[partitionId] = p.disappeared[partitionId][:1024]
 		}