Bug 27522 - Run With iOS Simulated Background Fetch Debugger does not call PerformFetch method
Summary: Run With iOS Simulated Background Fetch Debugger does not call PerformFetch m...
Alias: None
Product: iOS
Classification: Xamarin
Component: Debugger ()
Version: XI 8.6.0
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Rolf Bjarne Kvinge [MSFT]
Depends on:
Reported: 2015-02-27 18:32 UTC by Jon Goldberger [MSFT]
Modified: 2017-02-14 23:04 UTC (History)
5 users (show)

Is this bug a regression?: ---
Last known good build:

Test Project (20.26 KB, application/zip)
2015-02-27 18:32 UTC, Jon Goldberger [MSFT]

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Description Jon Goldberger [MSFT] 2015-02-27 18:32:44 UTC
Created attachment 10095 [details]
Test Project

## Description

When running an iOS project using Run With->iOS Simulated Background Fetch Debugger context menu, it is expected that the PerformFetch method will be called right away for debugging purposes. However this does not seem to be occurring.

## Steps to reproduce

1. Open the attached test project.

2. Right click on the project in the Solution Explorer and select Run With-> iOS Simulated Background Fetch Debugger.

Expected result: PerformFetch method will be called.

Actual result: method is not called.

## Note

Might not be a Xamarin issue, but it is also noted that PerformFetch does not seem to be called when the project is run on the simulator (after a long wait), but is called when run on device. To try to speed up when the method gets called, open and close the app a few times to make iOS think the app is used a lot which will cause PerformFetch to be called more often. The PerformFetch method was called on my device (iPhone 5s running iOS 8.1.3) after a few minutes of waiting, but not on the simulator.
Comment 1 Rolf Bjarne Kvinge [MSFT] 2015-03-03 13:30:15 UTC
After launching (using "Run -> Run With -> iOS Simulated Background Fetch Debugger"), do "Run ->Simulate iOS Background Fetch".
Comment 2 Jon Goldberger [MSFT] 2015-03-03 14:04:32 UTC
Thanks Rolf, sorry I missed that menu item. :-(
Comment 3 Niels 2016-06-23 07:55:59 UTC
PerformFetch never called: 

I heave tried several test projects, including the one attached in this bug report but PerformFetch is never called, not on a real device, neither on a simulator. 

I have tried the "Simulate iOS Background Fetch" option and set a breakpoint in the PerformFetch method but it is never hit. I have also run the test app for a couple of days on my device but the PerformFetch is never called. The Info.plist background modes are set correctly to "Enable Background Modes" and "Background Fetch"

I am running XS 5.10.3 (build 51) on a macbook pro with osx 10.10.5.
Real devices: Iphone 6S iOS 9.3.1, iPad mini iOS 9.3.2
Simulator: iPhone 6S iOS 9.2

Am I still missing something or are there any known issues here that I should be aware of?
Comment 4 Rolf Bjarne Kvinge [MSFT] 2016-06-23 09:33:24 UTC
Simulating background fetch should work in the simulator (there was a bug where it didn't work, but we fixed that for Xamarin.iOS 9.4). Maybe you can try a sample project that is known to work to determine if there's something different with your project: https://github.com/Redth/iOS.BackgroundFetch.Sample?
Comment 5 Niels 2016-06-23 10:06:25 UTC
Hi Rolf, I have just checked the sample project you provided. This project still uses MonoTouch so I had to migrate it to Xamarin.iOS Unified API and double checked the background modes. But the same issue occurs: I have set 2 breakpoints: 
1) in FinishedLaunching
2) in PerformFetch

breakpoint #1 is hit but #2 is hollow and is never hit when running the "Simulate iOS Background Fetch" option, both on simulator and real device (iPhone 6s ios 9.3.2)

Operating System
Mac OS X 10.10.5

Xamarin Studio Business
Version 5.10.3 (build 51)

Version: (Xamarin Business)

Would you be able to check on your side if this works? Thanks!
Comment 6 Niels 2016-06-23 11:29:46 UTC
Also, the Background.Sample uses the openweathermap api, which now requires an api key. After obtaining an api key I found out that the data scheme has changed, so this sample is outdated. Better use the attached sample because it doesn't use any third party api's.