android - Xamarin proguard.ParseException: Unknown option '' in line 1 of file 'Properties/proguard.cfg'

Question

I'm trying to use proguard with Xamarin. So I enabled it in project options (checked Enable ProGuard), and I created a file proguard.cfg in Properties, (as new Text file, is it right?) and checked the BuildAction -> ProguardConfiguration

The proguard file contains only a -keep configuration, with a comment. Whether I leave or remove the comment, I always get a parse error on line 1 :

# test comment 
-keep class !android.support.v7.view.menu.**, !android.support.design.internal.NavigationMenu, !android.support.design.internal.NavigationMenuPresenter, !android.support.design.internal.NavigationSubMenu, android.support.** {*;}

I get a Unknown option '?' in line 1 error.

/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets: Error: Tool exited with code: 1. Output: proguard.ParseException: Unknown option '?' in line 1 of file 'Properties/proguard.cfg'
included from argument number 10 at proguard.ConfigurationParser.parse(ConfigurationParser.java:191) at proguard.ProGuard.main(ProGuard.java:484) (WheezMe.Droid)

Any idea ?

Answer 1

I added this section of the docs awhile back to mention that you need to remove the BOM(Byte order mark):

Note: If you get an error like the following, then your configuration file contains a byte order mark (BOM), which the ProGuard tool cannot handle:

Unknown option '-keep' in line 1 of file 'proguard.cfg'

To prevent this problem, save your custom configuration file from a text editor that allows you to omit the BOM. For example, if you are saving from Notepad++, you can use the Encoding > Encode in UTF-8 Without BOM option to save your ProGuard configuration file without BOM.

https://developer.xamarin.com/guides/android/deployment,_testing,_and_metrics/publishing_an_application/part_1_-_preparing_an_application_for_release/#ProGuard

By all means you can use whatever method you'd like to remove the BOM. Notepad++ makes it pretty simple. Adding the full solution here to help others for visibility.

EDIT:

The proper link can be found here:

https://developer.xamarin.com/guides/android/deployment,_testing,_and_metrics/proguard/#File_Issues