fix destroy so incoming module vars get set

terraform/context.go

@@ -939,6 +939,22 @@ func (c *walkContext) planDestroyWalkFn() depgraph.WalkFunc {
 			// Build another walkContext for this module and walk it.
 			wc := c.Context.walkContext(c.Operation, m.Path)
 
+			// compute incoming vars
+			if m.Config != nil {
+				wc.Variables = make(map[string]string)
+
+				rc := NewResourceConfig(m.Config.RawConfig)
+				rc.interpolate(c, nil)
+				for k, v := range rc.Config {
+					wc.Variables[k] = v.(string)
+				}
+				for k, _ := range rc.Raw {
+					if _, ok := wc.Variables[k]; !ok {
+						wc.Variables[k] = config.UnknownVariableValue
+					}
+				}
+			}
+
 			// Set the graph to specifically walk this subgraph
 			wc.graph = m.Graph
 

terraform/context_test.go

@@ -3716,6 +3716,55 @@ func TestContextPlan_moduleDestroy(t *testing.T) {
 	}
 }
 
+func TestContextPlan_moduleDestroyMultivar(t *testing.T) {
+	m := testModule(t, "plan-module-destroy-multivar")
+	p := testProvider("aws")
+	p.DiffFn = testDiffFn
+	s := &State{
+		Modules: []*ModuleState{
+			&ModuleState{
+				Path:      rootModulePath,
+				Resources: map[string]*ResourceState{},
+			},
+			&ModuleState{
+				Path: []string{"root", "child"},
+				Resources: map[string]*ResourceState{
+					"aws_instance.foo.0": &ResourceState{
+						Type: "aws_instance",
+						Primary: &InstanceState{
+							ID: "bar0",
+						},
+					},
+					"aws_instance.foo.1": &ResourceState{
+						Type: "aws_instance",
+						Primary: &InstanceState{
+							ID: "bar1",
+						},
+					},
+				},
+			},
+		},
+	}
+	ctx := testContext(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: s,
+	})
+
+	plan, err := ctx.Plan(&PlanOpts{Destroy: true})
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(plan.String())
+	expected := strings.TrimSpace(testTerraformPlanModuleDestroyMultivarStr)
+	if actual != expected {
+		t.Fatalf("bad:\n%s", actual)
+	}
+}
+
 func TestContextPlan_pathVar(t *testing.T) {
 	cwd, err := os.Getwd()
 	if err != nil {

terraform/terraform_test.go

@@ -790,6 +790,24 @@ module.child:
     ID = bar
 `
 
+const testTerraformPlanModuleDestroyMultivarStr = `
+DIFF:
+
+module.child:
+  DESTROY MODULE
+  DESTROY: aws_instance.foo.0
+  DESTROY: aws_instance.foo.1
+
+STATE:
+
+<no state>
+module.child:
+  aws_instance.foo.0:
+    ID = bar0
+  aws_instance.foo.1:
+    ID = bar1
+`
+
 const testTerraformPlanModuleInputStr = `
 DIFF:
 

terraform/test-fixtures/plan-module-destroy-multivar/child/main.tf

@@ -0,0 +1,8 @@
+variable "instance_count" {
+  default = "1"
+}
+
+resource "aws_instance" "foo" {
+  count = "${var.instance_count}"
+  bar = "bar"
+}

terraform/test-fixtures/plan-module-destroy-multivar/main.tf

@@ -0,0 +1,5 @@
+module "child" {
+  source = "./child"
+  instance_count = "2"
+}
+