check(synchronize-folder-operation): local folder npe

app/src/main/java/com/owncloud/android/operations/SynchronizeFolderOperation.java

@@ -37,6 +37,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Vector;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -126,6 +127,10 @@ protected RemoteOperationResult run(OwnCloudClient client) {
         try {
             // get locally cached information about folder
             mLocalFolder = getStorageManager().getFileByPath(mRemotePath);
+            if (mLocalFolder == null) {
+                Log_OC.e(TAG, "Local folder is null, cannot run synchronize folder operation, remote path: " + mRemotePath);
+                return new RemoteOperationResult<>(ResultCode.FILE_NOT_FOUND);
+            }
 
             result = checkForChanges(client);
 
@@ -163,18 +168,17 @@ private RemoteOperationResult checkForChanges(OwnCloudClient client) throws Oper
 
         // remote request
         ReadFileRemoteOperation operation = new ReadFileRemoteOperation(mRemotePath);
-        RemoteOperationResult result = operation.execute(client);
-        if (result.isSuccess()) {
-            OCFile remoteFolder = FileStorageUtils.fillOCFile((RemoteFile) result.getData().get(0));
+        var result = operation.execute(client);
+        if (result.isSuccess() && result.getData().get(0) instanceof RemoteFile remoteFile) {
+            OCFile remoteFolder = FileStorageUtils.fillOCFile(remoteFile);
 
             // check if remote and local folder are different
             mRemoteFolderChanged = !(remoteFolder.getEtag().equalsIgnoreCase(mLocalFolder.getEtag()));
 
-            result = new RemoteOperationResult(ResultCode.OK);
+            result = new RemoteOperationResult<>(ResultCode.OK);
 
             Log_OC.i(TAG, "Checked " + user.getAccountName() + mRemotePath + " : " +
-                    (mRemoteFolderChanged ? "changed" : "not changed"));
-
+                (mRemoteFolderChanged ? "changed" : "not changed"));
         } else {
             // check failed
             if (result.getCode() == ResultCode.FILE_NOT_FOUND) {
@@ -549,12 +553,20 @@ public void cancel() {
         mCancellationRequested.set(true);
     }
 
-    public String getFolderPath() {
+    public Optional<String> getFolderNameFromPath() {
+        if (mLocalFolder == null) {
+            return Optional.empty();
+        }
+
         String path = mLocalFolder.getStoragePath();
         if (!TextUtils.isEmpty(path)) {
-            return path;
+            File folder = new File(path);
+            return Optional.of(folder.getName());
         }
-        return FileStorageUtils.getDefaultSavePathFor(user.getAccountName(), mLocalFolder);
+
+        String filepath = FileStorageUtils.getDefaultSavePathFor(user.getAccountName(), mLocalFolder);
+        File folder = new File(filepath);
+        return Optional.of(folder.getName());
     }
 
     private void startSyncFolderOperation(String path){

app/src/main/java/com/owncloud/android/utils/ErrorMessageAdapter.java

@@ -35,6 +35,7 @@
 
 import java.io.File;
 import java.net.SocketTimeoutException;
+import java.util.Optional;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -160,10 +161,13 @@ String getMessageForSynchronizeFolderOperation(
         Resources res) {
 
         if (!result.isSuccess() && result.getCode() == ResultCode.FILE_NOT_FOUND) {
-            return String.format(
-                res.getString(R.string.sync_current_folder_was_removed),
-                new File(operation.getFolderPath()).getName()
-                                );
+            Optional<String> folderName = operation.getFolderNameFromPath();
+            if (folderName.isEmpty()) {
+                return null;
+            }
+
+            String format = res.getString(R.string.sync_current_folder_was_removed);
+            return String.format(format, folderName.get());
         }
         return null;
     }
@@ -488,11 +492,14 @@ String getMessageForOperation(RemoteOperation operation, Resources res) {
         } else if (operation instanceof MoveFileOperation) {
             message = res.getString(R.string.move_file_error);
 
-        } else if (operation instanceof SynchronizeFolderOperation) {
-            String folderPathName = new File(
-                    ((SynchronizeFolderOperation) operation).getFolderPath()
-            ).getName();
-            message = String.format(res.getString(R.string.sync_folder_failed_content), folderPathName);
+        } else if (operation instanceof SynchronizeFolderOperation synchronizeFolderOperation) {
+            Optional<String> folderName = synchronizeFolderOperation.getFolderNameFromPath();
+            if (folderName.isEmpty()) {
+                return null;
+            }
+
+            String format = res.getString(R.string.sync_folder_failed_content);
+            message = String.format(format, folderName.get());
 
         } else if (operation instanceof CopyFileOperation) {
             message = res.getString(R.string.copy_file_error);