Save data but crashed at try super.save()

[gizcloud]

When I try to save data with Swift2.0. The program broke down at , When I ran again, the data has been saved into the database when fetch them. how to solve that?

  public override func save() throws {
        guard self.hasChanges else { return }

        try super.save()   <------------- This point

        var error: ErrorType? = nil
        self.rootSavingDataContext.performBlockAndWait {
            self.enableMergeFromRootSavingDataContext = false
            defer { self.enableMergeFromRootSavingDataContext = true }

            do {
                try self.rootSavingDataContext.save()
            }
            catch let innerError {
                error = innerError
            }
        }

        if let error = error {
            throw error
        }
    }

My Code is:

  @IBAction func doCreate(sender: AnyObject) {

        let dataContext = DataContext();
        let gang = dataContext.gangs.createEntity();
        gang.nick = randomStringWithLength(5);

        gang.nick_py = randomStringWithLength(5);


        do {
           try dataContext.save()
        }
        catch let error {
           print("data saved error \(error)")
        }
}



    }

[vmartinelli]

Hello. Do you have a description of the innerError?

[gizcloud]

[ssxenon01]

Hi @gizcloud did you find solution? I'm also getting this error 👍

[vmartinelli]

Without a description of the error is very difficult to say something. The screenshot you posted does not show it.

[vmartinelli]

I mean I need to know what is the result of the print.

[ssxenon01]

There where no error log. Just crash with pointer.
In my case:Error was I initialized DataContext() 2 times in 2 different controller. When i changed it to one. Error has gone.

[thellimist]

I had a similar bug.

let album = dataContext.collectionAlbums.filter({ $0.text ==  text}).first
album.user = user
if album != nil { // Adding this block fixed the bug
  do {
   try dataContext.save()
  }
  catch let error {
   QL4Error("error \(error)")
  }
}

[waltermvp]

Same issue with me the print never executes

[waltermvp]

Update:
Passing around one DataContext object instead of creating them over again solves this issue. Does is make sense to create a singleton function? @vmartinelli

[amayatsky]

I have the same issue which is resolved when I use static DataContext

[vmartinelli]

Well... Usually only one main thread context is used by an app. Other background contexts can be used as well (temporary or not). Anyway, can you test if this issue occurs using the version from develop branch as well?

[lie-an]

Hello, I'm having the same error.

I have tested using the version from develop branch as well.

I am saving JSON data (multiple entities) concurrently and the app crash in

try super.save()

inside DataContext.swift.

[amayatsky]

I had that problem too and ended up using a static instance:

extension DataContext {
    class var sharedInstance: DataContext {
        struct Static {
            static let instance: DataContext = DataContext()
        }
        return Static.instance
    }
}

I've also moved the saving to a single place, since I use the ACD for a cache only and don't care much about validity of the stored data:

func applicationDidEnterBackground(application: UIApplication) {
        do {
            try DataContext.sharedInstance.save()
            print("applicationDidEnterBackground data saved")
        } catch {
            print("applicationDidEnterBackground:\(error)")
        }   
    }