[Bug] Xamarin.Forms iOS 14 - 'SensorKit' not found error during debug build/launch

[mmacneil]

Description

Greetings,

After bumping up the Minimum System Version (MinimumOSVersion) from 13.6 to 14.0 and updating an iPad to iOS 14 we're unable to build/launch our application in debug mode from Visual Studio for Mac. The code compiles, builds, deploys, and launches without issue but quickly crashes as soon as it begins launching on the device. The app splash screen flashes up for a fraction of a second, and then it dies instantly. There are no exceptions thrown or any other visible output in the IDE I can see to indicate an error. The IDE remains in debug mode with Waiting for the debugger to connect to Mark's iPad on port ...

The device log does report the issue which seems to point to a missing SensorKit framework: '/System/Library/Frameworks/SensorKit.framework/SensorKit' not found

Incident Identifier: 45EB9EFA-B987-40C7-BE49-E150D7AFC983
CrashReporter Key:   1b617e530dfdeb11cc71e112e25d5095737c4d78
Hardware Model:      iPad7,5
Process:             App.iOS [387]
Path:                /private/var/containers/Bundle/Application/06EEA9D8-A820-4847-8AD8-15BBD4CB0510/App.app/App.iOS
Identifier:          com.company.app
Version:             14.0.10310.0 (5.0.0)
Code Type:           ARM-64 (Native)
Role:                Foreground
Parent Process:      launchd [1]
Coalition:           com.app [529]

Date/Time:           2020-10-19 14:31:05.2812 -0300
Launch Time:         2020-10-19 14:31:05.1731 -0300
OS Version:          iPhone OS 14.0.1 (18A393)
Release Type:        User
Baseband Version:    n/a
Report Version:      104 

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
Termination Description: DYLD, dyld: Using shared cache: 576E48BE-CF7D-3813-BCF6-3D1EFD8C96D3 | dependent dylib '/System/Library/Frameworks/SensorKit.framework/SensorKit' not found for '/private/var/containers/Bundle/Application/06EEA9D8-A820-4847-8AD8-15BBD4CB0510/app/app.iOS', tried but didn't find: '/System/Library/Frameworks/SensorKit.framework/SensorKit'
Highlighted by Thread:  0

Backtrace not available

Unknown thread crashed with ARM Thread State (64-bit):
    x0: 0x0000000000000006   x1: 0x0000000000000001   x2: 0x000000016b9c1f50   x3: 0x00000000000000d9
    x4: 0x000000016b9c1b50   x5: 0x0000000000000000   x6: 0x0000000000000000   x7: 0x0000000000000000
    x8: 0x0000000000000020   x9: 0x0000000000000009  x10: 0x6d6172662e74694b  x11: 0x65532f6b726f7765
   x12: 0x694b726f736e6553  x13: 0x77656d6172662e74  x14: 0x736e65532f6b726f  x15: 0x00202774694b726f
   x16: 0x0000000000000209  x17: 0x00000000000000bc  x18: 0x0000000000000000  x19: 0x0000000000000000
   x20: 0x000000016b9c1b50  x21: 0x00000000000000d9  x22: 0x000000016b9c1f50  x23: 0x0000000000000001
   x24: 0x0000000000000006  x25: 0x000000016b9c2818  x26: 0x000000010c0fc778  x27: 0x000000010c0fc000
   x28: 0x0000000000000000   fp: 0x000000016b9c1b20   lr: 0x000000010c0e0394
    sp: 0x000000016b9c1ae0   pc: 0x000000010c0d93e8 cpsr: 0x00000000
   esr: 0x00000000  Address size fault 

Binary images description not available 

Error Formulating Crash Report:
Failed to create CSSymbolicatorRef - corpse still valid ¯\_(ツ)_/¯`

Steps to Reproduce

1. Change MinimumOSVersion in info.plist from 13.6 to 14.0 within our existing project.

Expected Behavior

IDE builds and launches the application on the device as expected.

Actual Behavior

The application dies quickly when launched in debug.

Basic Information

• Version with issue: Xamarin.Forms 4.8.0.1560

• Last known good version: Xamarin.Forms 4.8.0.1560

• IDE: Visual Studio for Mac 8.7.8 (build 4)

• Platform Target Frameworks:

  • iOS: 14.0.0.0

• Affected Devices:
  iPad (6th gen) - 14.1

Workaround

Rolling back MinimumOSVersion in info.plist from 14.0 to 13.6.

[mmacneil]

Some more info - it appears a workaround is available by changing the Linking Behavior in the iOS project's build options from Don't Link to Link Framework SDKs Only. After this adjustment, the app launches and runs as expected. We also noticed when creating a new, blank iOS project targeting iOS 14 this setting defaults to Link Framework SDKs Only, and when flipped back to Don't Link the blank projects crashes in the same fashion.

[rolfbjarne]

Sounds like the device in question doesn't have the SensorKit framework, even though iOS 14 is supposed to (maybe because it's an iPad?)

My guess is that adding --weak-framework SensorKit to the additional mtouch arguments in the project's iOS Build options will work around the crash.

We'll probably have to treat this like CoreNFC, and always weak link.

[mmacneil]

Thanks, @rolfbjarne - I tried adding --weak-framework SensorKit to the mtouch args but still received the same result with the Don't Link linking option.

Also of note, I just applied the latest iOS update from Apple (14.1) on my iPad but unfortunately no luck. I updated the version in the issue description to reflect that change. We'll continue to use the Link Framework SDKs Only to bypass this for now, thanks!

[tipa]

I see the same issue in my Xamarin.iOS app - will there be any efforts to fix this?

[TheCaveOfWonders]

@rolfbjarne suggestion works, the proper syntax is --weak-framework=SensorKit.framework/SensorKit

[flimtix]

For me the workaround doesn't work. Because of another bug I need to set the behaviour to Don't Link. Is there another workaround or a fix?

Why does Xamarin try to access these frameworks? The SensorKit is only for iPhones and paired Apple Watches.

[flimtix]

@spouliot can you give an update on this issue? I saw tat you have been working on this... (commit) in #9142

[MattePozzy]

Still no answer from devs teams?..

[rolfbjarne]

If adding --weak-framework SensorKit to the additional mtouch arguments in the project's iOS build options does not make the app work, then please:

1. Add -v -v -v -v to the additional mtouch arguments in the project's iOS Build options (in addition to --weak-framework SensorKit).
2. Upload a diagnostic build log. The build can be found in the Build Output tab of the Errors pad in Visual Studio
   To get full build logs, set the log verbosity to diagnostic at the following locations:
   • On Visual Studio for Mac: Preferences > Projects > Build
   • On Visual Studio for Windows: Tools > Options > Projects and Solutions > Build and Run