core: fix `terraform show` with remote state

fixes #1810

command/show.go

@@ -6,7 +6,6 @@ import (
 	"os"
 	"strings"
 
-	statelib "github.com/hashicorp/terraform/state"
 	"github.com/hashicorp/terraform/terraform"
 )
 
@@ -66,16 +65,15 @@ func (c *ShowCommand) Run(args []string) int {
 				stateErr = err
 			}
 		}
-
 	} else {
-		// We should use the default state if it exists.
-		stateStore := &statelib.LocalState{Path: DefaultStateFilename}
-		if err := stateStore.RefreshState(); err != nil {
+		stateOpts := c.StateOpts()
+		stateOpts.RemoteCacheOnly = true
+		result, err := State(stateOpts)
+		if err != nil {
 			c.Ui.Error(fmt.Sprintf("Error reading state: %s", err))
 			return 1
 		}
-
-		state = stateStore.State()
+		state = result.State.State()
 		if state == nil {
 			c.Ui.Output("No state.")
 			return 0

command/show_test.go

@@ -4,6 +4,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/hashicorp/terraform/config/module"
@@ -124,6 +125,45 @@ func TestShow_plan(t *testing.T) {
 	}
 }
 
+func TestShow_noArgsRemoteState(t *testing.T) {
+	tmp, cwd := testCwd(t)
+	defer testFixCwd(t, tmp, cwd)
+
+	// Pretend like we have a local cache of remote state
+	remoteStatePath := filepath.Join(tmp, DefaultDataDir, DefaultStateFilename)
+	if err := os.MkdirAll(filepath.Dir(remoteStatePath), 0755); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	f, err := os.Create(remoteStatePath)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	err = terraform.WriteState(testState(), f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	ui := new(cli.MockUi)
+	c := &ShowCommand{
+		Meta: Meta{
+			ContextOpts: testCtxConfig(testProvider()),
+			Ui:          ui,
+		},
+	}
+
+	args := []string{}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: \n%s", ui.OutputWriter.String())
+	}
+
+	expected := "test_instance.foo"
+	actual := ui.OutputWriter.String()
+	if !strings.Contains(actual, expected) {
+		t.Fatalf("expected:\n%s\n\nto include: %q", actual, expected)
+	}
+}
+
 func TestShow_state(t *testing.T) {
 	originalState := testState()
 	statePath := testStateFile(t, originalState)