terraform: import verifies the refresh results in non-nil state

/cc @jen20

terraform/context_import_test.go

@@ -163,6 +163,44 @@ func TestContextImport_refresh(t *testing.T) {
 	}
 }
 
+func TestContextImport_refreshNil(t *testing.T) {
+	p := testProvider("aws")
+	ctx := testContext2(t, &ContextOpts{
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+	})
+
+	p.ImportStateReturn = []*InstanceState{
+		&InstanceState{
+			ID:        "foo",
+			Ephemeral: EphemeralState{Type: "aws_instance"},
+		},
+	}
+
+	p.RefreshFn = func(info *InstanceInfo, s *InstanceState) (*InstanceState, error) {
+		return nil, nil
+	}
+
+	state, err := ctx.Import(&ImportOpts{
+		Targets: []*ImportTarget{
+			&ImportTarget{
+				Addr: "aws_instance.foo",
+				ID:   "bar",
+			},
+		},
+	})
+	if err == nil {
+		t.Fatal("should error")
+	}
+
+	actual := strings.TrimSpace(state.String())
+	expected := "<no state>"
+	if actual != expected {
+		t.Fatalf("bad: \n%s", actual)
+	}
+}
+
 func TestContextImport_module(t *testing.T) {
 	p := testProvider("aws")
 	ctx := testContext2(t, &ContextOpts{

terraform/eval_import_state.go

@@ -51,3 +51,26 @@ func (n *EvalImportState) Eval(ctx EvalContext) (interface{}, error) {
 
 	return nil, nil
 }
+
+// EvalImportStateVerify verifies the state after ImportState and
+// after the refresh to make sure it is non-nil and valid.
+type EvalImportStateVerify struct {
+	Info  *InstanceInfo
+	Id    string
+	State **InstanceState
+}
+
+// TODO: test
+func (n *EvalImportStateVerify) Eval(ctx EvalContext) (interface{}, error) {
+	state := *n.State
+	if state.Empty() {
+		return nil, fmt.Errorf(
+			"import %s (id: %s): Terraform detected a resource with this ID doesn't\n"+
+				"exist. Please verify the ID is correct. You cannot import non-existent\n"+
+				"resources using Terraform import.",
+			n.Info.HumanId(),
+			n.Id)
+	}
+
+	return nil, nil
+}

terraform/transform_import_state.go

@@ -195,7 +195,7 @@ func (n *graphNodeImportStateSub) EvalTree() EvalNode {
 
 	// Build the resource info
 	info := &InstanceInfo{
-		Id:         n.State.ID,
+		Id:         fmt.Sprintf("%s.%s", n.Target.Type, n.Target.Name),
 		ModulePath: n.Path_,
 		Type:       n.State.Ephemeral.Type,
 	}
@@ -221,6 +221,11 @@ func (n *graphNodeImportStateSub) EvalTree() EvalNode {
 				Info:     info,
 				Output:   &state,
 			},
+			&EvalImportStateVerify{
+				Info:  info,
+				Id:    n.State.ID,
+				State: &state,
+			},
 			&EvalWriteState{
 				Name:         key.String(),
 				ResourceType: info.Type,