objective c - ios 8: Bundle path changes

Question

I have an iOS app that stores the absolute path of files in a database and in generated html documents. I just recently updated my iPhone to iOS 8 and now when ever I run the app it seems that the app is installed in a different directory every re-compile. For example on the first build/run [[NSBundle mainBundle] bundlePath] returns something different on the next build/run. What is going on? Is this a new feature of Apple?

Update: A bug report was created

Code example:

If I run the following line over multiple build/runs then I will get a different result each time.

#define kOLD_PATH @"oldPath"
NSString* newPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];
NSString* oldPath = [[NSUserDefaults standardUserDefaults] objectForKey:kOLD_PATH];

NSLog(@"New Path: %@", newPath);
NSLog(@"Old Path: %@", oldPath);
NSLog(@"Result: %@", [oldPath isEqualToString:newPath] ? @"Same" : @"Changed");

[[NSUserDefaults standardUserDefaults] setObject:newPath forKey:kOLD_PATH];
[[NSUserDefaults standardUserDefaults] synchronize];

The output looks like this over multiple runs

New Path: /var/mobile/Containers/Data/Application/4FFCE2CB-580D-409A-90CB-EF2B8A1FB653/Library
Old Path: /var/mobile/Containers/Data/Application/B038B2DA-F85D-4E18-A5F1-8635834EC454/Library
Result: Changed

Full Disclosure: In my app the user imports a web page (ePub) that has resources. The resources are stored with the web page. The web page also accesses resources that are part of the app bundle. To achieve this when I load the web page the base url is set to the directory the web page is in and the bundle resources are accessed via absolute file paths. Now that file paths change on every update this is broken. I tried creating symbolic links to the bundle resources but that also fails un subsequent updates.

Answer 1

In iOS 8, The file system layout of app containers has changed. Applications and their content are no longer stored in one root directory.

From the iOS 8 Release Notes:

The file system layout of app containers has changed on disk. Rather than relying on hard-coded directory structure, use the NSSearchPathForDirectoriesInDomains function or the URLForDirectory:inDomain:appropriateForURL:create:error: method of the NSFileManager class. See Accessing Files and Directories in File System Programming Guide.

This is not a bug. Make sure you use the recommended APIs (from the above quote) and you won't have a problem.

So, If you are trying to access a bundled resource you added to the project, you would use:

[[NSBundle mainBundle] pathForResource:@"resourceName" ofType:@"extension"];

But if you want to use something that you put in the documents directory, you would use:

[[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject] stringByAppendingPathComponent:@"resourceName.extension"];