From fc4ac52014c2ed80f72b1d21278ea4ecdf3aa0ec Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Thu, 19 May 2016 10:46:51 -0700
Subject: [PATCH] Module variables not being interpolated

Variables weren't being interpolated during the Input phase, causing a
syntax error on the interpolation string. Adding `walkInput` to the
EvalTree operations prevents skipping the interpolation step.
---
 terraform/context_input_test.go               | 23 +++++++++++++++++++
 terraform/eval_context_builtin.go             |  1 +
 terraform/eval_interpolate.go                 |  4 +---
 terraform/graph_config_node_output.go         |  2 +-
 terraform/interpolate.go                      |  1 +
 .../input-interpolate-var/child/main.tf       |  5 ++++
 .../input-interpolate-var/main.tf             |  7 ++++++
 .../input-interpolate-var/source/main.tf      |  1 +
 8 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 terraform/test-fixtures/input-interpolate-var/child/main.tf
 create mode 100644 terraform/test-fixtures/input-interpolate-var/main.tf
 create mode 100644 terraform/test-fixtures/input-interpolate-var/source/main.tf

diff --git a/terraform/context_input_test.go b/terraform/context_input_test.go
index dae45e0d0..08e017b4c 100644
--- a/terraform/context_input_test.go
+++ b/terraform/context_input_test.go
@@ -569,3 +569,26 @@ func TestContext2Input_varPartiallyComputed(t *testing.T) {
 		t.Fatalf("err: %s", err)
 	}
 }
+
+// Module variables weren't being interpolated during the Input walk.
+// https://github.com/hashicorp/terraform/issues/5322
+func TestContext2Input_interpolateVar(t *testing.T) {
+	input := new(MockUIInput)
+
+	m := testModule(t, "input-interpolate-var")
+	p := testProvider("null")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"template": testProviderFuncFixed(p),
+		},
+		UIInput: input,
+	})
+
+	if err := ctx.Input(InputModeStd); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}
diff --git a/terraform/eval_context_builtin.go b/terraform/eval_context_builtin.go
index 4dff93a4c..d85cb77fc 100644
--- a/terraform/eval_context_builtin.go
+++ b/terraform/eval_context_builtin.go
@@ -291,6 +291,7 @@ func (ctx *BuiltinEvalContext) Interpolate(
 			Path:     ctx.Path(),
 			Resource: r,
 		}
+
 		vs, err := ctx.Interpolater.Values(scope, cfg.Variables)
 		if err != nil {
 			return nil, err
diff --git a/terraform/eval_interpolate.go b/terraform/eval_interpolate.go
index 063473079..6825ff590 100644
--- a/terraform/eval_interpolate.go
+++ b/terraform/eval_interpolate.go
@@ -1,8 +1,6 @@
 package terraform
 
-import (
-	"github.com/hashicorp/terraform/config"
-)
+import "github.com/hashicorp/terraform/config"
 
 // EvalInterpolate is an EvalNode implementation that takes a raw
 // configuration and interpolates it.
diff --git a/terraform/graph_config_node_output.go b/terraform/graph_config_node_output.go
index 8410102d2..ac364a308 100644
--- a/terraform/graph_config_node_output.go
+++ b/terraform/graph_config_node_output.go
@@ -44,7 +44,7 @@ func (n *GraphNodeConfigOutput) DependentOn() []string {
 // GraphNodeEvalable impl.
 func (n *GraphNodeConfigOutput) EvalTree() EvalNode {
 	return &EvalOpFilter{
-		Ops: []walkOperation{walkRefresh, walkPlan, walkApply, walkDestroy},
+		Ops: []walkOperation{walkRefresh, walkPlan, walkApply, walkDestroy, walkInput},
 		Node: &EvalSequence{
 			Nodes: []EvalNode{
 				&EvalWriteOutput{
diff --git a/terraform/interpolate.go b/terraform/interpolate.go
index 0a627aca6..8ed74490d 100644
--- a/terraform/interpolate.go
+++ b/terraform/interpolate.go
@@ -129,6 +129,7 @@ func (i *Interpolater) valueModuleVar(
 	n string,
 	v *config.ModuleVariable,
 	result map[string]ast.Variable) error {
+
 	// If we're computing all dynamic fields, then module vars count
 	// and we mark it as computed.
 	if i.Operation == walkValidate {
diff --git a/terraform/test-fixtures/input-interpolate-var/child/main.tf b/terraform/test-fixtures/input-interpolate-var/child/main.tf
new file mode 100644
index 000000000..9a2ff39cc
--- /dev/null
+++ b/terraform/test-fixtures/input-interpolate-var/child/main.tf
@@ -0,0 +1,5 @@
+variable "list" { }
+resource "template_file" "temp" {
+  count     = "${length(split(",", var.list))}"
+  template  = "foo"
+}
diff --git a/terraform/test-fixtures/input-interpolate-var/main.tf b/terraform/test-fixtures/input-interpolate-var/main.tf
new file mode 100644
index 000000000..ae6cf627f
--- /dev/null
+++ b/terraform/test-fixtures/input-interpolate-var/main.tf
@@ -0,0 +1,7 @@
+module "source" {
+  source = "./source"
+}
+module "child" {
+  source  = "./child"
+  list = "${module.source.list}"
+}
diff --git a/terraform/test-fixtures/input-interpolate-var/source/main.tf b/terraform/test-fixtures/input-interpolate-var/source/main.tf
new file mode 100644
index 000000000..fb7b33fb3
--- /dev/null
+++ b/terraform/test-fixtures/input-interpolate-var/source/main.tf
@@ -0,0 +1 @@
+output "list" { value = "foo,bar,baz" }