Switch to root folder if current folder cannot be loaded

CHANGELOG.unreleased.md

@@ -25,6 +25,7 @@ For upgrade instructions, please check the [migration guide](MIGRATIONS.released
 - Added more documentation for N5 and Neuroglancer precomputed web upload. [#7622](https://github.com/scalableminds/webknossos/pull/7622)
 - Added the config key `webKnossos.user.timeTrackingOnlyWithSignificantChanges`, which when set to `true` will only track time if the user has made significant changes to the annotation. [#7627](https://github.com/scalableminds/webknossos/pull/7627)
 - Only display UI elements to launch background jobs if the (worker) backend actually supports them. [#7591](https://github.com/scalableminds/webknossos/pull/7591)
+- If the current dataset folder in the dashboard cannot be found (e.g., because somebody else deleted it), the page navigates to the root folder automatically. [#7669](https://github.com/scalableminds/webknossos/pull/7669)
 
 ### Fixed
 - Fixed rare SIGBUS crashes of the datastore module that were caused by memory mapping on unstable file systems. [#7528](https://github.com/scalableminds/webknossos/pull/7528)

frontend/javascripts/dashboard/dataset/dataset_collection_context.tsx

@@ -86,7 +86,7 @@ export default function DatasetCollectionContextProvider({
   const mostRecentlyUsedActiveFolderId = usePrevious(activeFolderId, true);
   const [isChecking, setIsChecking] = useState(false);
   const isMutating = useIsMutating() > 0;
-  const { data: folder } = useFolderQuery(activeFolderId);
+  const { data: folder, isError: didFolderLoadingError } = useFolderQuery(activeFolderId);
 
   const [selectedDatasets, setSelectedDatasets] = useState<APIDatasetCompact[]>([]);
   const [selectedFolder, setSelectedFolder] = useState<FolderItem | null>(null);
@@ -110,12 +110,16 @@ export default function DatasetCollectionContextProvider({
   useEffect(() => {
     // Persist last active folder to localStorage. We
     // check folder against null to avoid that invalid ids are persisted.
-    if (activeFolderId != null && folder != null) {
+    if (activeFolderId != null && folder != null && !didFolderLoadingError) {
       UserLocalStorage.setItem(ACTIVE_FOLDER_ID_STORAGE_KEY, activeFolderId);
     } else {
       UserLocalStorage.removeItem(ACTIVE_FOLDER_ID_STORAGE_KEY);
     }
-  }, [folder, activeFolderId]);
+
+    if (didFolderLoadingError) {
+      setActiveFolderId(null);
+    }
+  }, [folder, activeFolderId, didFolderLoadingError]);
 
   const folderHierarchyQuery = useFolderHierarchyQuery();
   const datasetsInFolderQuery = useDatasetsInFolderQuery(

frontend/javascripts/dashboard/dataset/queries.tsx

@@ -46,6 +46,13 @@ export function useFolderQuery(folderId: string | null) {
     {
       refetchOnWindowFocus: false,
       enabled: folderId != null,
+      // Avoid default retry delay with exponential back-off
+      // to shorten the delay after which webKnossos will switch
+      // to the root folder.
+      // This is relevant for the case where the current folder
+      // does not exist, anymore (e.g., was deleted by somebody
+      // else).
+      retryDelay: 500,
     },
   );
 }