From 1a6c67d106571853c77c08ddf19859da76ac06d4 Mon Sep 17 00:00:00 2001
From: David Bresson <dbresson@compellon.com>
Date: Fri, 3 Feb 2017 08:05:35 -0800
Subject: [PATCH 1/2] extend config merge test to test merging to empty config

---
 command/agent/config_test.go | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/command/agent/config_test.go b/command/agent/config_test.go
index 35d90f8b568..9cce09e24f9 100644
--- a/command/agent/config_test.go
+++ b/command/agent/config_test.go
@@ -20,7 +20,21 @@ var (
 )
 
 func TestConfig_Merge(t *testing.T) {
+	c0 := &Config{}
+
 	c1 := &Config{
+		Telemetry:      &Telemetry{},
+		Client:         &ClientConfig{},
+		Server:         &ServerConfig{},
+		Ports:          &Ports{},
+		Addresses:      &Addresses{},
+		AdvertiseAddrs: &AdvertiseAddrs{},
+		Atlas:          &AtlasConfig{},
+		Vault:          &config.VaultConfig{},
+		Consul:         &config.ConsulConfig{},
+	}
+
+	c2 := &Config{
 		Region:                    "global",
 		Datacenter:                "dc1",
 		NodeName:                  "node1",
@@ -136,7 +150,7 @@ func TestConfig_Merge(t *testing.T) {
 		},
 	}
 
-	c2 := &Config{
+	c3 := &Config{
 		Region:                    "region2",
 		Datacenter:                "dc2",
 		NodeName:                  "node2",
@@ -271,9 +285,11 @@ func TestConfig_Merge(t *testing.T) {
 		},
 	}
 
-	result := c1.Merge(c2)
-	if !reflect.DeepEqual(result, c2) {
-		t.Fatalf("bad:\n%#v\n%#v", result, c2)
+	result := c0.Merge(c1)
+	result = result.Merge(c2)
+	result = result.Merge(c3)
+	if !reflect.DeepEqual(result, c3) {
+		t.Fatalf("bad:\n%#v\n%#v", result, c3)
 	}
 }
 

From a49759f1b877ac43d8067f6f94af36584eb2492c Mon Sep 17 00:00:00 2001
From: David Bresson <dbresson@compellon.com>
Date: Fri, 3 Feb 2017 08:39:57 -0800
Subject: [PATCH 2/2] avoid nil pointer dereference

---
 command/agent/config.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/command/agent/config.go b/command/agent/config.go
index f842662f196..dc90c740fdc 100644
--- a/command/agent/config.go
+++ b/command/agent/config.go
@@ -898,7 +898,10 @@ func (a *ClientConfig) Merge(b *ClientConfig) *ClientConfig {
 	if b.ClientMinPort != 0 {
 		result.ClientMinPort = b.ClientMinPort
 	}
-	if b.Reserved != nil {
+	if result.Reserved == nil && b.Reserved != nil {
+		reserved := *b.Reserved
+		result.Reserved = &reserved
+	} else if b.Reserved != nil {
 		result.Reserved = result.Reserved.Merge(b.Reserved)
 	}
 	if b.GCInterval != 0 {