From 54b961630dc13e3a5802f4f931a72a8425bda939 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Wed, 24 Jun 2015 21:23:37 -0700
Subject: [PATCH] terraform: module computed vars with splat vars don't error

---
 terraform/context_test.go                       | 17 +++++++++++++++++
 terraform/interpolate.go                        |  8 ++++++++
 .../refresh-module-computed-var/child/main.tf   |  5 +++++
 .../refresh-module-computed-var/main.tf         |  8 ++++++++
 4 files changed, 38 insertions(+)
 create mode 100644 terraform/test-fixtures/refresh-module-computed-var/child/main.tf
 create mode 100644 terraform/test-fixtures/refresh-module-computed-var/main.tf

diff --git a/terraform/context_test.go b/terraform/context_test.go
index db16e4e0894d..fb8d98ce00c2 100644
--- a/terraform/context_test.go
+++ b/terraform/context_test.go
@@ -1935,6 +1935,23 @@ func TestContext2Refresh_targetedCountIndex(t *testing.T) {
 	}
 }
 
+func TestContext2Refresh_moduleComputedVar(t *testing.T) {
+	p := testProvider("aws")
+	m := testModule(t, "refresh-module-computed-var")
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+	})
+
+	// This was failing (see GH-2188) at some point, so this test just
+	// verifies that the failure goes away.
+	if _, err := ctx.Refresh(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}
+
 func TestContext2Refresh_delete(t *testing.T) {
 	p := testProvider("aws")
 	m := testModule(t, "refresh-basic")
diff --git a/terraform/interpolate.go b/terraform/interpolate.go
index 15b51fcb2f0c..c51000a3720e 100644
--- a/terraform/interpolate.go
+++ b/terraform/interpolate.go
@@ -437,6 +437,14 @@ func (i *Interpolater) computeResourceMultiVariable(
 	}
 
 	if len(values) == 0 {
+		// If the operation is refresh, it isn't an error for a value to
+		// be unknown. Instead, we return that the value is computed so
+		// that the graph can continue to refresh other nodes. It doesn't
+		// matter because the config isn't interpolated anyways.
+		if i.Operation == walkRefresh {
+			return config.UnknownVariableValue, nil
+		}
+
 		return "", fmt.Errorf(
 			"Resource '%s' does not have attribute '%s' "+
 				"for variable '%s'",
diff --git a/terraform/test-fixtures/refresh-module-computed-var/child/main.tf b/terraform/test-fixtures/refresh-module-computed-var/child/main.tf
new file mode 100644
index 000000000000..38260d6373c5
--- /dev/null
+++ b/terraform/test-fixtures/refresh-module-computed-var/child/main.tf
@@ -0,0 +1,5 @@
+variable "value" {}
+
+output "value" {
+    value = "${var.value}"
+}
diff --git a/terraform/test-fixtures/refresh-module-computed-var/main.tf b/terraform/test-fixtures/refresh-module-computed-var/main.tf
new file mode 100644
index 000000000000..a8573327b154
--- /dev/null
+++ b/terraform/test-fixtures/refresh-module-computed-var/main.tf
@@ -0,0 +1,8 @@
+module "child" {
+    source = "./child"
+    value = "${join(" ", aws_instance.test.*.id)}"
+}
+
+resource "aws_instance" "test" {
+    value = "yes"
+}