From c6c0984b8ec4b4c3e560cdd63a7ee3e20fec96b5 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Mon, 19 Feb 2018 20:18:14 +0100
Subject: [PATCH] Ensure we always release the AddressEnvelope when doing DNS
 queries.

Motivation:

When we do DNS queries we need to ensure we always release the AddressEnvelope.

Modifications:

Also release the AddressEnvelope if the original resolution was done in the meantime and we did not cancel the extra query yet.

Result:

Should fix [#7713]
---
 .../java/io/netty/resolver/dns/DnsNameResolverContext.java | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverContext.java b/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverContext.java
index 7c215b1199..2eea34536e 100644
--- a/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverContext.java
+++ b/resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverContext.java
@@ -325,6 +325,13 @@ abstract class DnsNameResolverContext<T> {
 
                 if (promise.isDone() || future.isCancelled()) {
                     queryLifecycleObserver.queryCancelled(allowedQueries);
+
+                    // Check if we need to release the envelope itself. If the query was cancelled the getNow() will
+                    // return null as well as the Future will be failed with a CancellationException.
+                    AddressedEnvelope<DnsResponse, InetSocketAddress> result = future.getNow();
+                    if (result != null) {
+                        result.release();
+                    }
                     return;
                 }