command: disable backup with "-" [GH-1072]

/cc @phinze

command/apply_test.go

@@ -1113,6 +1113,12 @@ func TestApply_disableBackup(t *testing.T) {
 	if err == nil || !os.IsNotExist(err) {
 		t.Fatalf("backup should not exist")
 	}
+
+	// Ensure there is no literal "-"
+	_, err = os.Stat("-")
+	if err == nil || !os.IsNotExist(err) {
+		t.Fatalf("backup should not exist")
+	}
 }
 
 func testHttpServer(t *testing.T) net.Listener {

command/state.go

@@ -154,9 +154,11 @@ func State(opts *StateOpts) (*StateResult, error) {
 			backupPath = opts.BackupPath
 		}
 
-		result.State = &state.BackupState{
-			Real: result.State,
-			Path: backupPath,
+		if backupPath != "-" {
+			result.State = &state.BackupState{
+				Real: result.State,
+				Path: backupPath,
+			}
 		}
 	}