project state loading should error if can’t load default

src/reducers/project-state.js

@@ -17,7 +17,7 @@ const START_AUTO_UPDATING = 'scratch-gui/project-state/START_AUTO_UPDATING';
 const START_CREATING_NEW = 'scratch-gui/project-state/START_CREATING_NEW';
 const START_ERROR = 'scratch-gui/project-state/START_ERROR';
 const START_FETCHING_NEW = 'scratch-gui/project-state/START_FETCHING_NEW';
-const START_LOADING_VM_FILE_UPLOAD = 'scratch-gui/project-state/START_LOADING_FILE_UPLOAD';
+const START_LOADING_VM_FILE_UPLOAD = 'scratch-gui/project-state/START_LOADING_VM_FILE_UPLOAD';
 const START_MANUAL_UPDATING = 'scratch-gui/project-state/START_MANUAL_UPDATING';
 const START_REMIXING = 'scratch-gui/project-state/START_REMIXING';
 const START_UPDATING_BEFORE_CREATING_COPY = 'scratch-gui/project-state/START_UPDATING_BEFORE_CREATING_COPY';
@@ -435,10 +435,21 @@ const onLoadedProject = (loadingState, canSave, success) => {
         default:
             return;
         }
+    } else {
+        switch (loadingState) {
+        case LoadingState.LOADING_VM_WITH_ID:
+        case LoadingState.LOADING_VM_FILE_UPLOAD:
+            return {
+                type: RETURN_TO_SHOWING
+            };
+        case LoadingState.LOADING_VM_NEW_DEFAULT:
+            return {
+                type: START_ERROR
+            };
+        default:
+            return;
+        }
     }
-    return {
-        type: RETURN_TO_SHOWING
-    };
 };
 
 const doneUpdatingProject = loadingState => {