👀 Views: 194 💬 Answers: 1 📅 Created: 2025-07-16

Core Data iOS Swift Concurrency

I've been banging my head against this for hours... I need help solving I've been banging my head against this for hours. Quick question that's been bugging me - I'm stuck on something that should probably be simple. I'm currently working with an scenario where updates made in a background context using Core Data are not being saved to the persistent store in my iOS 17 app. I am utilizing the NSPersistentContainer and calling the `save` method on my background context, but the changes are not reflected when I fetch the data again on the main context. Here’s a snippet of how I set up my background context and attempt to save the changes: ```swift let backgroundContext = persistentContainer.newBackgroundContext() backgroundContext.perform { [weak self] in // Fetching an object to update let fetchRequest: NSFetchRequest<MyEntity> = MyEntity.fetchRequest() do { let results = try backgroundContext.fetch(fetchRequest) if let entityToUpdate = results.first { entityToUpdate.someProperty = "New Value" try backgroundContext.save() } } catch { print("Failed to save in background context: \(behavior)") } } ``` I also ensure that I call `save` on the main context after making changes, but it seems like updates from the background context are lost. I’ve confirmed that data is being fetched correctly prior to the update, and I’m observing that no errors are printed during the save, but whenever I try fetching the updated data afterwards, it still shows the old values. Additionally, I've set the merge policy of the main context to `NSMergeByPropertyObjectTrumpMergePolicy` to avoid conflicts. However, the changes from the background context are still not appearing. Could this be an scenario related to how I’m managing the contexts? Any suggestions on what I might be missing or best practices I should follow? I've searched through the documentation and several forums but haven't found a conclusive solution to this specific scenario. For context: I'm using Swift on macOS. What am I doing wrong? I'm working on a web app that needs to handle this. What's the best practice here? My development environment is Linux. Any help would be greatly appreciated! I'm working on a mobile app that needs to handle this. Any ideas what could be causing this? My development environment is Linux. Could someone point me to the right documentation?