swift - iOS 9 - "attempt to delete and reload the same index path" -

this error:

coredata: error: serious application error. exception caught delegate of nsfetchedresultscontroller during call -controllerdidchangecontent:. attempt delete , reload same index path ( {length = 2, path = 0 - 0}) userinfo (null)

this typical nsfetchedresultscontrollerdelegate:

func controllerwillchangecontent(controller: nsfetchedresultscontroller) {     tableview.beginupdates() }  func controller(controller: nsfetchedresultscontroller, didchangesection sectioninfo: nsfetchedresultssectioninfo, atindex sectionindex: int, forchangetype type: nsfetchedresultschangetype) {      let indexset = nsindexset(index: sectionindex)      switch type {     case .insert:         tableview.insertsections(indexset, withrowanimation: .fade)     case .delete:         tableview.deletesections(indexset, withrowanimation: .fade)     case .update:         fallthrough     case .move:         tableview.reloadsections(indexset, withrowanimation: .fade)     } }  func controller(controller: nsfetchedresultscontroller, didchangeobject anobject: nsmanagedobject, atindexpath indexpath: nsindexpath?, forchangetype type: nsfetchedresultschangetype, newindexpath: nsindexpath?) {      switch type {     case .insert:         if let newindexpath = newindexpath {             tableview.insertrowsatindexpaths([newindexpath], withrowanimation: .fade)         }     case .delete:         if let indexpath = indexpath {             tableview.deleterowsatindexpaths([indexpath], withrowanimation: .fade)         }     case .update:         if let indexpath = indexpath {             tableview.reloadrowsatindexpaths([indexpath], withrowanimation: .none)         }     case .move:         if let indexpath = indexpath {             if let newindexpath = newindexpath {                 tableview.deleterowsatindexpaths([indexpath], withrowanimation: .fade)                 tableview.insertrowsatindexpaths([newindexpath], withrowanimation: .fade)             }         }     } }  func controllerdidchangecontent(controller: nsfetchedresultscontroller) {     tableview.endupdates() } 

in viewdidload():

private func setuponcefetchedresultscontroller() {      if fetchedresultscontroller == nil {         let context = nsmanagedobjectcontext.mr_defaultcontext()         let fetchreguest = nsfetchrequest(entityname: "dborder")         let datedescriptor = nssortdescriptor(key: "date", ascending: false)          fetchreguest.predicate = nspredicate(format: "user.identifier = %@", dbappsettings.currentuser!.identifier )         fetchreguest.sortdescriptors = [datedescriptor]         fetchreguest.fetchlimit = 10         fetchedresultscontroller = nsfetchedresultscontroller(fetchrequest: fetchreguest, managedobjectcontext: context, sectionnamekeypath: "identifier", cachename: nil)         fetchedresultscontroller.delegate = self          try! fetchedresultscontroller.performfetch()     } } 

this seems bug in ios 9 (which still beta) , discussed in apple developer forum

• ios 9 coredata nsfetchedresultscontroller update causes blank rows in uicollectionview/uitableview

i can confirm problem ios 9 simulator xcode 7 beta 3. observed updated managed object, didchangeobject: delegate method called twice: once nsfetchedresultschangeupdate event , again nsfetchedresultschangemove event (and indexpath == newindexpath).

adding explicit check indexpath != newindexpath suggested in above thread seems solve problem:

        case .move:             if indexpath != newindexpath {                 tableview.deleterowsatindexpaths([indexpath!], withrowanimation: .fade)                 tableview.insertrowsatindexpaths([newindexpath!], withrowanimation: .fade)         }