don't load the backend when -state is provided

When using a `state` command, if the `-state` flag is provided we do not
want to modify the Backend state. In this case we should always create a
local state instance.

The backup flag was also being ignored, and some tests were relying on
that, which have been fixed.

command/state_meta.go

@@ -18,6 +18,16 @@ type StateMeta struct{}
 // backups to be timestamped rather than just the original state path plus a
 // backup path.
 func (c *StateMeta) State(m *Meta) (state.State, error) {
+	var realState state.State
+	backupPath := m.backupPath
+	stateOutPath := m.statePath
+
+	// use the specified state
+	if m.statePath != "" {
+		realState = &state.LocalState{
+			Path: m.statePath,
+		}
+	} else {
 		// Load the backend
 		b, err := m.Backend(nil)
 		if err != nil {
@@ -38,26 +48,33 @@ func (c *StateMeta) State(m *Meta) (state.State, error) {
 			panic(err)
 		}
 		localB := localRaw.(*backendlocal.Local)
-	_, stateOutPath, _ := localB.StatePaths(env)
+		_, stateOutPath, _ = localB.StatePaths(env)
 		if err != nil {
 			return nil, err
 		}
 
+		realState = s
+	}
+
+	// We always backup state commands, so set the back if none was specified
+	// (the default is "-", but some tests bypass the flag parsing).
+	if backupPath == "-" || backupPath == "" {
 		// Determine the backup path. stateOutPath is set to the resulting
 		// file where state is written (cached in the case of remote state)
-	backupPath := fmt.Sprintf(
+		backupPath = fmt.Sprintf(
 			"%s.%d%s",
 			stateOutPath,
 			time.Now().UTC().Unix(),
 			DefaultBackupExtension)
+	}
 
 	// Wrap it for backups
-	s = &state.BackupState{
-		Real: s,
+	realState = &state.BackupState{
+		Real: realState,
 		Path: backupPath,
 	}
 
-	return s, nil
+	return realState, nil
 }
 
 // filterInstance filters a single instance out of filter results.

command/state_mv_test.go

@@ -213,12 +213,7 @@ func TestStateMv_backupExplicit(t *testing.T) {
 	// Test it is correct
 	testStateOutput(t, statePath, testStateMvOutput)
 
-	// Test we have backups
-	backups := testStateBackups(t, filepath.Dir(statePath))
-	if len(backups) != 1 {
-		t.Fatalf("bad: %#v", backups)
-	}
-	testStateOutput(t, backups[0], testStateMvOutputOriginal)
+	// Test backup
 	testStateOutput(t, backupPath, testStateMvOutputOriginal)
 }
 

command/state_rm_test.go

@@ -130,12 +130,7 @@ func TestStateRm_backupExplicit(t *testing.T) {
 	// Test it is correct
 	testStateOutput(t, statePath, testStateRmOutput)
 
-	// Test we have backups
-	backups := testStateBackups(t, filepath.Dir(statePath))
-	if len(backups) != 1 {
-		t.Fatalf("bad: %#v", backups)
-	}
-	testStateOutput(t, backups[0], testStateRmOutputOriginal)
+	// Test backup
 	testStateOutput(t, backupPath, testStateRmOutputOriginal)
 }