Open Radar

 
Summary:
App is unable to resume a previously interrupted download task. 
(Session is created with backgroundSessionConfiguration) 
If the app gets terminated while download task is in progress, NSURLSessionTaskDelegate gets called and it receives the error with download task resume data. 
App stores the received data and then tries to create a download task using -[NSURLSession downloadTaskWithResumeData:].

Error received:
*** -[NSKeyedUnarchiver initForReadingWithData:]: data is NULL

Task gets created but most of it's properties are not set, for instance currentRequest or originalRequest.

That results in this error:
Invalid resume data for background download. Background downloads must use http or https and must download to an accessible file.

Steps to Reproduce:
1. Create a project for an app that uses background download with NSURLSession
2. Start downloading a file
3. Manually terminate the app before the download
4. Try to recreate a download task using resume data received in the 
- [URLSession: task:didCompleteWithError:] method

Expected Results:
Task to resume download is created and previous download continues, as it does when the app is running on iOS9.

Actual Results:
-[NSURLSession downloadTaskWithResumeData:].

Error received:
*** -[NSKeyedUnarchiver initForReadingWithData:]: data is NULL

Task gets created but most of it's properties are not set, for instance currentRequest or originalRequest.

That results in this error:
Invalid resume data for background download. Background downloads must use http or https and must download to an accessible file.


Version:
iOS 10.0 (14A5322e)

Configuration:
iPhone 6s, WiFi