From f3d1fb3aff94fc1595e6111cfc778eccc31cba69 Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Fri, 9 Mar 2018 18:38:41 -0500
Subject: [PATCH] failing test for interpolated count from plan

An interpolated count value that is determined during plan, is lost
during plan serialization, causing apply to fail when the interpolation
string can't be evaluated.
---
 terraform/context_apply_test.go               | 67 +++++++++++++++++++
 .../apply-interpolated-count/main.tf          | 11 +++
 2 files changed, 78 insertions(+)
 create mode 100644 terraform/test-fixtures/apply-interpolated-count/main.tf

diff --git a/terraform/context_apply_test.go b/terraform/context_apply_test.go
index 28e42b02e8..69da40cfcb 100644
--- a/terraform/context_apply_test.go
+++ b/terraform/context_apply_test.go
@@ -9472,5 +9472,72 @@ func TestContext2Apply_providersFromState(t *testing.T) {
 
 		})
 	}
+}
+
+func TestContext2Apply_plannedInterpolatedCount(t *testing.T) {
+	m := testModule(t, "apply-interpolated-count")
+
+	p := testProvider("aws")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+
+	providerResolver := ResourceProviderResolverFixed(
+		map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+	)
+
+	s := &State{
+		Modules: []*ModuleState{
+			&ModuleState{
+				Path: rootModulePath,
+				Resources: map[string]*ResourceState{
+					"aws_instance.test": {
+						Type: "aws_instance",
+						Primary: &InstanceState{
+							ID: "foo",
+						},
+						Provider: "provider.aws",
+					},
+				},
+			},
+		},
+	}
+
+	ctx := testContext2(t, &ContextOpts{
+		Module:           m,
+		ProviderResolver: providerResolver,
+		State:            s,
+	})
+
+	plan, err := ctx.Plan()
+	if err != nil {
+		t.Fatalf("plan failed: %s", err)
+	}
 
+	// We'll marshal and unmarshal the plan here, to ensure that we have
+	// a clean new context as would be created if we separately ran
+	// terraform plan -out=tfplan && terraform apply tfplan
+	var planBuf bytes.Buffer
+	err = WritePlan(plan, &planBuf)
+	if err != nil {
+		t.Fatalf("failed to write plan: %s", err)
+	}
+	plan, err = ReadPlan(&planBuf)
+	if err != nil {
+		t.Fatalf("failed to read plan: %s", err)
+	}
+
+	ctx, err = plan.Context(&ContextOpts{
+		ProviderResolver: providerResolver,
+	})
+	if err != nil {
+		t.Fatalf("failed to create context for plan: %s", err)
+	}
+
+	// Applying the plan should now succeed
+	_, err = ctx.Apply()
+	if err != nil {
+		t.Fatalf("apply failed: %s", err)
+	}
 }
diff --git a/terraform/test-fixtures/apply-interpolated-count/main.tf b/terraform/test-fixtures/apply-interpolated-count/main.tf
new file mode 100644
index 0000000000..c4ed06dc70
--- /dev/null
+++ b/terraform/test-fixtures/apply-interpolated-count/main.tf
@@ -0,0 +1,11 @@
+variable "instance_count" {
+  default = 1
+}
+
+resource "aws_instance" "test" {
+  count = "${var.instance_count}"
+}
+
+resource "aws_instance" "dependent" {
+  count = "${aws_instance.test.count}"
+}