From d37bb87bf240e26997a83f96244c8caba7914cc8 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Fri, 30 Sep 2016 11:29:59 -0700
Subject: [PATCH] terraform: ResourceConfig.DeepCopy should handle the nil case

---
 terraform/resource.go      | 5 +++++
 terraform/resource_test.go | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/terraform/resource.go b/terraform/resource.go
index db6db9ffd..937efdbe4 100644
--- a/terraform/resource.go
+++ b/terraform/resource.go
@@ -98,6 +98,11 @@ func NewResourceConfig(c *config.RawConfig) *ResourceConfig {
 // to modify any of the structures that are part of the resource config without
 // affecting the original configuration.
 func (c *ResourceConfig) DeepCopy() *ResourceConfig {
+	// DeepCopying a nil should return a nil to avoid panics
+	if c == nil {
+		return nil
+	}
+
 	// Copy, this will copy all the exported attributes
 	copy, err := copystructure.Config{Lock: true}.Copy(c)
 	if err != nil {
diff --git a/terraform/resource_test.go b/terraform/resource_test.go
index 85792fc2e..ab6a2273b 100644
--- a/terraform/resource_test.go
+++ b/terraform/resource_test.go
@@ -239,6 +239,14 @@ func TestResourceConfigGet(t *testing.T) {
 	}
 }
 
+func TestResourceConfigDeepCopy_nil(t *testing.T) {
+	var nilRc *ResourceConfig
+	actual := nilRc.DeepCopy()
+	if actual != nil {
+		t.Fatalf("bad: %#v", actual)
+	}
+}
+
 func TestResourceConfigEqual_nil(t *testing.T) {
 	var nilRc *ResourceConfig
 	notNil := NewResourceConfig(nil)