From 13433687cbbb9cfd00df23920a8b6df9234063aa Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Thu, 8 Mar 2018 11:39:29 -0500
Subject: [PATCH] filter null output values from state

While null values should not normally appear in a state file, we should
filter the values rather than crash.
---
 .../providers/terraform/data_source_state.go  |  4 +++-
 .../terraform/data_source_state_test.go       | 23 ++++++++++++++++++
 .../test-fixtures/null_outputs.tfstate        | 24 +++++++++++++++++++
 3 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 builtin/providers/terraform/test-fixtures/null_outputs.tfstate

diff --git a/builtin/providers/terraform/data_source_state.go b/builtin/providers/terraform/data_source_state.go
index 1f0fbea48..e6797eb4d 100644
--- a/builtin/providers/terraform/data_source_state.go
+++ b/builtin/providers/terraform/data_source_state.go
@@ -118,7 +118,9 @@ func dataSourceRemoteStateRead(d *schema.ResourceData, meta interface{}) error {
 		log.Println("[DEBUG] empty remote state")
 	} else {
 		for key, val := range remoteState.RootModule().Outputs {
-			outputMap[key] = val.Value
+			if val.Value != nil {
+				outputMap[key] = val.Value
+			}
 		}
 	}
 
diff --git a/builtin/providers/terraform/data_source_state_test.go b/builtin/providers/terraform/data_source_state_test.go
index bfabd27b1..f80b738be 100644
--- a/builtin/providers/terraform/data_source_state_test.go
+++ b/builtin/providers/terraform/data_source_state_test.go
@@ -63,6 +63,20 @@ func TestState_complexOutputs(t *testing.T) {
 	})
 }
 
+// outputs should never have a null value, but don't crash if we ever encounter
+// them.
+func TestState_nullOutputs(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccState_nullOutputs,
+			},
+		},
+	})
+}
+
 func TestEmptyState_defaults(t *testing.T) {
 	resource.UnitTest(t, resource.TestCase{
 		PreCheck:  func() { testAccPreCheck(t) },
@@ -142,6 +156,15 @@ resource "terraform_remote_state" "foo" {
 	}
 }`
 
+const testAccState_nullOutputs = `
+resource "terraform_remote_state" "foo" {
+	backend = "local"
+
+	config {
+		path = "./test-fixtures/null_outputs.tfstate"
+	}
+}`
+
 const testAccEmptyState_defaults = `
 data "terraform_remote_state" "foo" {
 	backend = "local"
diff --git a/builtin/providers/terraform/test-fixtures/null_outputs.tfstate b/builtin/providers/terraform/test-fixtures/null_outputs.tfstate
new file mode 100644
index 000000000..fa27a1563
--- /dev/null
+++ b/builtin/providers/terraform/test-fixtures/null_outputs.tfstate
@@ -0,0 +1,24 @@
+{
+    "version": 3,
+    "terraform_version": "0.7.0",
+    "serial": 3,
+    "modules": [
+        {
+            "path": [
+                "root"
+            ],
+            "outputs": {
+                "map": {
+                    "sensitive": false,
+                    "type": "map",
+                    "value": null
+                },
+                "list": {
+                    "sensitive": false,
+                    "type": "list",
+                    "value": null
+                }
+            }
+        }
+    ]
+}