From 983e4f13c613ae361b52984abde1a6397e549d09 Mon Sep 17 00:00:00 2001
From: James Nugent <james@jen20.com>
Date: Thu, 23 Jun 2016 21:11:36 +0100
Subject: [PATCH] core: Add context test for empty lists as module outputs

This test illustrates a failure which occurs during the Input walk, if
an interpolation is used with the input of a splat operation resulting
in a multi-variable.

The bug was found during use of the RC2, but does not correspond to an
open issue at present.
---
 terraform/context_input_test.go               | 21 +++++++++++++++++++
 .../main.tf                                   |  9 ++++++++
 .../moda/main.tf                              |  3 +++
 .../modb/main.tf                              |  7 +++++++
 4 files changed, 40 insertions(+)
 create mode 100644 terraform/test-fixtures/input-module-computed-output-element/main.tf
 create mode 100644 terraform/test-fixtures/input-module-computed-output-element/moda/main.tf
 create mode 100644 terraform/test-fixtures/input-module-computed-output-element/modb/main.tf

diff --git a/terraform/context_input_test.go b/terraform/context_input_test.go
index 08e017b4c..f953645c8 100644
--- a/terraform/context_input_test.go
+++ b/terraform/context_input_test.go
@@ -49,6 +49,27 @@ func TestContext2Input(t *testing.T) {
 	}
 }
 
+func TestContext2Input_moduleComputedOutputElement(t *testing.T) {
+	m := testModule(t, "input-module-computed-output-element")
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+	})
+
+	p.InputFn = func(i UIInput, c *ResourceConfig) (*ResourceConfig, error) {
+		return c, nil
+	}
+
+	if err := ctx.Input(InputModeStd); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}
+
 func TestContext2Input_badVarDefault(t *testing.T) {
 	m := testModule(t, "input-bad-var-default")
 	p := testProvider("aws")
diff --git a/terraform/test-fixtures/input-module-computed-output-element/main.tf b/terraform/test-fixtures/input-module-computed-output-element/main.tf
new file mode 100644
index 000000000..bb96e24a3
--- /dev/null
+++ b/terraform/test-fixtures/input-module-computed-output-element/main.tf
@@ -0,0 +1,9 @@
+module "b" {
+  source = "./modb"
+}
+
+module "a" {
+  source = "./moda"
+
+  single_element = "${element(module.b.computed_list, 0)}"
+}
diff --git a/terraform/test-fixtures/input-module-computed-output-element/moda/main.tf b/terraform/test-fixtures/input-module-computed-output-element/moda/main.tf
new file mode 100644
index 000000000..eb09eb192
--- /dev/null
+++ b/terraform/test-fixtures/input-module-computed-output-element/moda/main.tf
@@ -0,0 +1,3 @@
+variable "single_element" {
+  type = "string"
+}
diff --git a/terraform/test-fixtures/input-module-computed-output-element/modb/main.tf b/terraform/test-fixtures/input-module-computed-output-element/modb/main.tf
new file mode 100644
index 000000000..ebe4a7eff
--- /dev/null
+++ b/terraform/test-fixtures/input-module-computed-output-element/modb/main.tf
@@ -0,0 +1,7 @@
+resource "aws_instance" "test" {
+  count = 3
+}
+
+output "computed_list" {
+  value = ["${aws_instance.test.*.id}"]
+}