terraform: test count == zero

terraform/context.go

@@ -1559,7 +1559,6 @@ func (c *walkContext) computeResourceMultiVariable(
 	// TODO: Not use only root module
 	module := c.Context.state.RootModule()
 
-	// TODO: handle computed here
 	count, err := cr.Count()
 	if err != nil {
 		return "", fmt.Errorf(
@@ -1568,6 +1567,11 @@ func (c *walkContext) computeResourceMultiVariable(
 			err)
 	}
 
+	// If we have no count, return empty
+	if count == 0 {
+		return "", nil
+	}
+
 	var values []string
 	for i := 0; i < count; i++ {
 		id := fmt.Sprintf("%s.%d", v.ResourceId(), i)

terraform/context_test.go

@@ -2490,6 +2490,29 @@ func TestContextPlan_countVar(t *testing.T) {
 	}
 }
 
+func TestContextPlan_countZero(t *testing.T) {
+	m := testModule(t, "plan-count-zero")
+	p := testProvider("aws")
+	p.DiffFn = testDiffFn
+	ctx := testContext(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+	})
+
+	plan, err := ctx.Plan(nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(plan.String())
+	expected := strings.TrimSpace(testTerraformPlanCountZeroStr)
+	if actual != expected {
+		t.Fatalf("bad:\n%s", actual)
+	}
+}
+
 func TestContextPlan_countDecreaseToOne(t *testing.T) {
 	m := testModule(t, "plan-count-dec")
 	p := testProvider("aws")

terraform/terraform_test.go

@@ -477,6 +477,18 @@ STATE:
 <no state>
 `
 
+const testTerraformPlanCountZeroStr = `
+DIFF:
+
+CREATE: aws_instance.bar
+  foo:  "" => ""
+  type: "" => "aws_instance"
+
+STATE:
+
+<no state>
+`
+
 const testTerraformPlanCountVarStr = `
 DIFF:
 

terraform/test-fixtures/plan-count-zero/main.tf

@@ -0,0 +1,8 @@
+resource "aws_instance" "foo" {
+    count = 0
+    foo = "foo"
+}
+
+resource "aws_instance" "bar" {
+    foo = "${aws_instance.foo.*.foo}"
+}