From abedeafd77df3d03ac9bd9c002dbf94b018f493e Mon Sep 17 00:00:00 2001
From: Manfred Karrer <mk@nucleo.io>
Date: Sun, 23 Sep 2018 20:10:16 -0500
Subject: [PATCH] PeerGroup: Add check to not duplicate peers

The inactives collection contained duplicated peerAddresses after
connection loss and reconnect.
We add a check to see if the to-get-added peerAddress is not already
in the collection and only add it if it is absent.
This problem was not discovered when using the public network as the
chance that same peerAddress get reported is pretty low. But with our
provided nodes we got frequently duplicates.

Fixes https://github.com/bisq-network/bisq/issues/1703

Cherry-pick https://github.com/bisq-network/bitcoinj/commit/05e675ed925a7fc91af5810c0d272e8869781b0d
---
 .../java/org/bitcoinj/core/PeerGroup.java     | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/bitcoinj/core/PeerGroup.java b/core/src/main/java/org/bitcoinj/core/PeerGroup.java
index 7a2c9b7f540c..7aaa1ad0beca 100644
--- a/core/src/main/java/org/bitcoinj/core/PeerGroup.java
+++ b/core/src/main/java/org/bitcoinj/core/PeerGroup.java
@@ -582,7 +582,9 @@ public void go() {
                 if (retryTime > now) {
                     long delay = retryTime - now;
                     log.info("Waiting {} msec before next connect attempt {}", delay, addrToTry == null ? "" : "to " + addrToTry);
-                    inactives.add(addrToTry);
+
+                    if (!isAlreadyAdded(addrToTry))
+                        inactives.add(addrToTry);
                     executor.schedule(this, delay, TimeUnit.MILLISECONDS);
                     return;
                 }
@@ -596,6 +598,17 @@ public void go() {
         }
     };
 
+    private boolean isAlreadyAdded(PeerAddress peerAddress) {
+        boolean isAlreadyAdded = false;
+        for (PeerAddress a : inactives) {
+            if (a.getHostname() != null && a.getHostname().equals(peerAddress.getHostname())) {
+                isAlreadyAdded = true;
+                break;
+            }
+        }
+        return isAlreadyAdded;
+    }
+
     private void triggerConnections() {
         // Run on a background thread due to the need to potentially retry and back off in the background.
         if (!executor.isShutdown())
@@ -996,7 +1009,10 @@ private boolean addInactive(PeerAddress peerAddress) {
                 return false;
             }
             backoffMap.put(peerAddress, new ExponentialBackoff(peerBackoffParams));
-            inactives.offer(peerAddress);
+
+            if (!isAlreadyAdded(peerAddress))
+                inactives.offer(peerAddress);
+
             return true;
         } finally {
             lock.unlock();