iCloud files keep reappearing after deleting

Question

I have the following setup: My app writes UIDocument instances to iCloud. The files get synced and everything works fine. But when I try to delete them they keep reappearing. Before I delete the files I close them. Here is the code that deletes the files:

- (void)deleteDocumentWithName:(NSString*)name completion:(void (^)(BOOL success))completion
{
[self stopQuery];
NSURL* toDelete = [self URLForFileWithName:name];

UIDocument* doc = [[UIDocument alloc] initWithFileURL:toDelete];

void (^deleteDocument)() = ^() {
    // Wrap in file coordinator
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void) {

        NSFileCoordinator* fileCoordinator = [[NSFileCoordinator alloc] initWithFilePresenter:nil];
        [fileCoordinator coordinateWritingItemAtURL:toDelete
                                            options:NSFileCoordinatorWritingForDeleting
                                              error:nil
                                         byAccessor:^(NSURL* writingURL) {
                                             // Simple delete to start
                                             NSFileManager* fileManager = [[NSFileManager alloc] init];
                                             NSError* error = nil;
                                             [fileManager removeItemAtURL:writingURL error:&error];

                                             if (error) {
                                                 LogError(@"%s - error while deleting file: %@", __PRETTY_FUNCTION__, error);
                                             }

                                             dispatch_async(dispatch_get_main_queue(), ^{
                                                 [_files removeObject:toDelete];

                                                 if (completion) {
                                                     completion((error == nil));
                                                 }

                                                 [self startQuery];
                                             });
                                         }];
    });
};

if (doc) {
    if (doc.documentState == UIDocumentStateNormal) {
        [doc closeWithCompletionHandler:^(BOOL success) {
            if (success) {
                deleteDocument();
            } else {
                if (completion) {
                    completion(NO);
                }
            }
        }];
    } else {
        deleteDocument();
    }
}
}

After this method was executed I get several NSMetadataQueryDidFinishGatheringNotifications. First it does not contain the deleted file. Then another NSMetadataQueryDidFinishGatheringNotification gets caught and it contains the deleted file again.

I can't find the reason for this. Any help is appreciated.

Why do you set up a document before you delete it? That seems unnecessary. At a guess I would say you're deleting the file on disk, but UIDocument's autosave is kicking in and saving it again. Are you certain it's closed when you perform the delete? Also, it depends on how your query is set up, but stopping and starting the query while performing a delete seems unnecessary. Also stopQuery doesn't necessarily stop immediately (if you need this probably use disableUpdates instead) - from the docs for stopQuery: `The receiver first completes gathering any unprocessed results.` — Rob Glassey, Aug 20 '13 at 12:17
Thanks for your response. I didn't figure out what the problem was but by removing the whole threading and background studd and by deleting the files directly vie the file manager solved the problem. for me the code seems a little bit buggy and dirty now. but hey, it works ;-) — ralphbert, Aug 26 '13 at 08:39
That's good! If you see documents resurrecting in future, check you don't have an instance variable somewhere else that has an open copy of that same document. No matter how often you delete off disk, if there's a UIDocument instance hanging onto an open copy somewhere else in your app, auto-save is likely to resurrect it. You need to make sure that *instance* has it's copy of the file closed too. But IMHO threading and background stuff, while really cool when it works, can be a right pain in the ass to get working! There are so many gotchas to watch out for. It's worth it though. — Rob Glassey, Aug 26 '13 at 09:29
@RobGlassey Your comment helped me a lot because making sure that `UIDocument` is closed and deallocated not only solved this file reappearance issue but also a non-trivial increased memory footprint issue in my app too. Thanks! — HuaTham, Jan 09 '18 at 07:37

score 0 · Answer 1 · answered May 06 '17 at 10:17

I faced similar issue. Remove the encapsulation of NSFileCoordinator instantiation from GCD, then you will be able to perform the delete operation (despite  documentation that it's preferable to have this operation in the background thread, which is odd because doing so actually causes this unable-to-delete issue in the first place)

void (^deleteDocument)() = ^() {
    NSFileCoordinator* fileCoordinator = [[NSFileCoordinator alloc] initWithFilePresenter:nil];
        [fileCoordinator coordinateWritingItemAtURL:toDelete
            options:NSFileCoordinatorWritingForDeleting
            error:nil
            byAccessor:^(NSURL* writingURL) {
            // Simple delete to start
            NSFileManager* fileManager = [[NSFileManager alloc] init];
            NSError* error = nil;
            [fileManager removeItemAtURL:writingURL error:&error];

            if (error) {
            LogError(@"%s - error while deleting file: %@", __PRETTY_FUNCTION__, error);
            }

            [_files removeObject:toDelete];

            if (completion) {
            completion((error == nil));
            }

            [self startQuery];
        }];
};

iCloud files keep reappearing after deleting

1 Answers1