From 22f09b487b9e48d363f515cbc65241f65132565d Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 20 Oct 2014 23:08:17 -0700
Subject: [PATCH] terraform: refresh ignores variables with no values [GH-478]

---
 terraform/context.go                          | 20 ++++++++++++-------
 terraform/context_test.go                     | 16 +++++++++++++++
 .../child/main.tf                             |  9 +++++++++
 .../main.tf                                   |  8 ++++++++
 4 files changed, 46 insertions(+), 7 deletions(-)
 create mode 100644 terraform/test-fixtures/refresh-module-input-computed-output/child/main.tf
 create mode 100644 terraform/test-fixtures/refresh-module-input-computed-output/main.tf

diff --git a/terraform/context.go b/terraform/context.go
index 47b9d1fae..e2d8bbd33 100644
--- a/terraform/context.go
+++ b/terraform/context.go
@@ -1611,19 +1611,25 @@ func (c *walkContext) computeResourceVariable(
 	// Get the relevant module
 	module := c.Context.state.ModuleByPath(c.Path)
 
-	r, ok := module.Resources[id]
-	if !ok {
-		if v.Multi && v.Index == 0 {
+	var r *ResourceState
+	if module != nil {
+		var ok bool
+		r, ok = module.Resources[id]
+		if !ok && v.Multi && v.Index == 0 {
 			r, ok = module.Resources[v.ResourceId()]
 		}
 		if !ok {
-			return "", fmt.Errorf(
-				"Resource '%s' not found for variable '%s'",
-				id,
-				v.FullKey())
+			r = nil
 		}
 	}
 
+	if r == nil {
+		return "", fmt.Errorf(
+			"Resource '%s' not found for variable '%s'",
+			id,
+			v.FullKey())
+	}
+
 	if r.Primary == nil {
 		goto MISSING
 	}
diff --git a/terraform/context_test.go b/terraform/context_test.go
index ef4b3f5b1..5ad260763 100644
--- a/terraform/context_test.go
+++ b/terraform/context_test.go
@@ -4110,6 +4110,22 @@ func TestContextRefresh_modules(t *testing.T) {
 	}
 }
 
+func TestContextRefresh_moduleInputComputedOutput(t *testing.T) {
+	m := testModule(t, "refresh-module-input-computed-output")
+	p := testProvider("aws")
+	p.DiffFn = testDiffFn
+	ctx := testContext(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+	})
+
+	if _, err := ctx.Refresh(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}
+
 // GH-70
 func TestContextRefresh_noState(t *testing.T) {
 	p := testProvider("aws")
diff --git a/terraform/test-fixtures/refresh-module-input-computed-output/child/main.tf b/terraform/test-fixtures/refresh-module-input-computed-output/child/main.tf
new file mode 100644
index 000000000..fff03a60f
--- /dev/null
+++ b/terraform/test-fixtures/refresh-module-input-computed-output/child/main.tf
@@ -0,0 +1,9 @@
+variable "input" {}
+
+resource "aws_instance" "foo" {
+    foo = "${var.input}"
+}
+
+output "foo" {
+    value = "${aws_instance.foo.foo}"
+}
diff --git a/terraform/test-fixtures/refresh-module-input-computed-output/main.tf b/terraform/test-fixtures/refresh-module-input-computed-output/main.tf
new file mode 100644
index 000000000..3a0576434
--- /dev/null
+++ b/terraform/test-fixtures/refresh-module-input-computed-output/main.tf
@@ -0,0 +1,8 @@
+module "child" {
+    input = "${aws_instance.bar.foo}"
+    source = "./child"
+}
+
+resource "aws_instance" "bar" {
+    compute = "foo"
+}