Debugging on watchOS device

Notes

• Make sure the phone is connected to wifi (same network as the mac).
• Make sure "Debug over WiFi" is enabled for both the watch app project and the watch extension project
• Debugging is slow. In my tests it takes ~60 seconds + upload time (depends on the size of the app; calculate approx 60 seconds per 10mb for the watch app (myapp.app/Watch)) to hit a breakpoint at launch.
• It's flaky. If it doesn't work, try again a couple of times.
• Always use the watch charger. Without the charger it's much flakier.
• If the device doesn't show up as a target in the IDE, check if "Connect via network" (wireless debugging) is enabled for the phone in Xcode, and if so, disable it, and instead connect to the phone using the USB cable.

Known issues

• Symptom: the app doesn't launch on the watch (just a spinning wheel)

  This is printed to the device log (the signifant string is other version in use):

  Aug 30 13:37:44 WatchA gizmoappd[93] : (Error) WatchKit: <SPGizmoPlugInManager.m __72-[SPGizmoPlugInManager beginUsingExtension:serverIdentifier:completion:]_block_invoke:1120> could not activate plugin com.xamarin.testapp.watchkitapp.watchkitextension (error:Error Domain=PlugInKit Code=16 "other version in use: <PKPlugin: 0x15da4f80 com.xamarin.testapp.watchkitapp.watchkitextension(${BundleShortVersion}) (guid) 0(0) /private/var/containers/Bundle/Application/(guid)/unified-test-appsrtfh.app/PlugIns/testapp.appex>" UserInfo={NSLocalizedDescription=other version in use: <PKPlugin: 0x15da4f80 com.xamarin.testapp.watchkitapp.watchkitextension(${BundleShortVersion}) (guid) 0(0) /private/var/containers/Bundle/Application/(guid)/testapp.app/PlugIns/testapp.appex>})

  Workaround: reboot the watch

When something doesn't work

• Make sure you have the latest versions of everything (Xcode, Xamarin Studio, Xamarin.iOS) installed.
• Reboot everything (watch + phone + mac) and try again.
• File a bug (see below for information to include in the bug report).

Logs to fetch when filing a bug

• Execute the following in a terminal:

    echo 123456789 > ~/.mlaunch-verbosity
  

• Make sure to capture the device log

  • If using watchOS 3, the device log has to be enabled by installing the sysdiagnose profile that can be downloaded here: https://developer.apple.com/bug-reporting/profiles-and-logs/?platform=watchos. Follow Apple's Instructions to install it (except that you can just open that page on the phone and download the profile there, no need to email it to yourself).

  • If using watchOS 3, you might also want to capture the device log by invoking mlaunch directly and redirecting to a file (because there will be a lot of output once the sysdiagnose profile is installed):

    /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/bin/mlaunch --logdev --devname "Name of device (UUID works as well)" > mylog.txt
    

  • You can get the name of the device by executing:

    /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/bin/mlaunch --listdev
    

• Reproduce again (you'll get a lot of output in the Application Output if things are working correctly).

• Lower the verbosity again:

    rm -f ~/.mlaunch-verbosity
  

• Attach both the device log and the Application Output to the bug (as attachments / gists).