Default/Static interface method desugar remapping not working in .NET 7

[radimitrov]

Android application type

Android for .NET (net6.0-android, etc.)

Affected platform version

VS 2022, net7.0-android

Description

App crashes at runtime for debug build with a JNI error related to default/static Java interface method binding. Doesn't matter if the debugger is attached. Might be related to #7125 but reverting to the old binding behaviour with <AndroidBoundInterfacesContainStaticAndDefaultInterfaceMethods>false</AndroidBoundInterfacesContainStaticAndDefaultInterfaceMethods> didn't help. Same for true value.

Steps to Reproduce

Bind any Java library with a default static interface method.

Did you find any workaround?

Release build

Relevant log output

12-16 22:24:43.893 18210 18210 F DEBUG   : signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
12-16 22:24:43.893 18210 18210 F DEBUG   : Abort message: 'java_vm_ext.cc:542] JNI DETECTED ERROR IN APPLICATION: can't call static org.eclipse.tm4e.core.registry.IThemeSource org.eclipse.tm4e.core.registry.IThemeSource$-CC.fromString(org.eclipse.tm4e.core.registry.IThemeSource$ContentType, java.lang.String) with class java.lang.Class<org.eclipse.tm4e.core.registry.IThemeSource>'
12-16 22:24:43.893 18210 18210 F DEBUG   :     x0  0000000000000000  x1  00000000000046e8  x2  0000000000000006  x3  0000000000000008
12-16 22:24:43.893 18210 18210 F DEBUG   :     x4  fefeff734dce4667  x5  fefeff734dce4667  x6  fefeff734dce4667  x7  7f7f7f7f7fff7f7f
12-16 22:24:43.893 18210 18210 F DEBUG   :     x8  0000000000000083  x9  dd61bb06df041932  x10 0000000000000000  x11 fffffffc7ffffbdf
12-16 22:24:43.893 18210 18210 F DEBUG   :     x12 0000000000000001  x13 ffffffffffffffff  x14 ffffffffff000000  x15 ffffffffffffffff
12-16 22:24:43.893 18210 18210 F DEBUG   :     x16 00000074528692b0  x17 0000007452788cd0  x18 0000000000000010  x19 00000000000046e8
12-16 22:24:43.893 18210 18210 F DEBUG   :     x20 00000000000046e8  x21 00000073be9f5b00  x22 000000000000000b  x23 00000073cdd27443
12-16 22:24:43.893 18210 18210 F DEBUG   :     x24 00000073cdd272f7  x25 0000000000000001  x26 0000007fd92f07e0  x27 0000000000000043
12-16 22:24:43.893 18210 18210 F DEBUG   :     x28 00000073ce513720  x29 0000007fd92f0690
12-16 22:24:43.893 18210 18210 F DEBUG   :     sp  0000007fd92f0650  lr  000000745277c144  pc  000000745277c16c
12-16 22:24:43.923 18210 18210 F DEBUG   : 
12-16 22:24:43.923 18210 18210 F DEBUG   : backtrace:
12-16 22:24:43.923 18210 18210 F DEBUG   :     #00 pc 000000000002216c  /system/lib64/libc.so (abort+116)
12-16 22:24:43.923 18210 18210 F DEBUG   :     #01 pc 0000000000465684  /system/lib64/libart.so (art::Runtime::Abort(char const*)+1196)
12-16 22:24:43.923 18210 18210 F DEBUG   :     #02 pc 0000000000008ce0  /system/lib64/libbase.so (android::base::LogMessage::~LogMessage()+724)
12-16 22:24:43.923 18210 18210 F DEBUG   :     #03 pc 00000000002e5ec8  /system/lib64/libart.so (art::JavaVMExt::JniAbort(char const*, char const*)+1640)
12-16 22:24:43.924 18210 18210 F DEBUG   :     #04 pc 00000000002e6038  /system/lib64/libart.so (art::JavaVMExt::JniAbortV(char const*, char const*, std::__va_list)+116)
12-16 22:24:43.924 18210 18210 F DEBUG   :     #05 pc 00000000000fdabc  /system/lib64/libart.so (art::(anonymous namespace)::ScopedCheck::AbortF(char const*, ...)+148)
12-16 22:24:43.924 18210 18210 F DEBUG   :     #06 pc 00000000001017d0  /system/lib64/libart.so (art::(anonymous namespace)::ScopedCheck::CheckMethodAndSig(art::ScopedObjectAccess&, _jobject*, _jclass*, _jmethodID*, art::Primitive::Type, art::InvokeType)+1160)
12-16 22:24:43.924 18210 18210 F DEBUG   :     #07 pc 0000000000101e40  /system/lib64/libart.so (art::(anonymous namespace)::CheckJNI::CallMethodA(char const*, _JNIEnv*, _jobject*, _jclass*, _jmethodID*, jvalue*, art::Primitive::Type, art::InvokeType)+748)
12-16 22:24:43.924 18210 18210 F DEBUG   :     #08 pc 000000000004d680  /data/app/com.companyname.AndroidBindingsJNICrashes-OMT4AzuyDOaf_ESYip9Szg==/lib/arm64/libmonodroid.so (java_interop_jnienv_call_static_object_method_a+48)
12-16 22:24:43.924 18210 18210 F DEBUG   :     #09 pc 00000000002af4c4  /data/app/com.companyname.AndroidBindingsJNICrashes-OMT4AzuyDOaf_ESYip9Szg==/lib/arm64/libmonosgen-2.0.so
12-16 22:24:43.924 18210 18210 F DEBUG   :     #10 pc 00000000002ae210  /data/app/com.companyname.AndroidBindingsJNICrashes-OMT4AzuyDOaf_ESYip9Szg==/lib/arm64/libmonosgen-2.0.so
12-16 22:24:43.924 18210 18210 F DEBUG   :     #11 pc 00000000002a48a0  /data/app/com.companyname.AndroidBindingsJNICrashes-OMT4AzuyDOaf_ESYip9Szg==/lib/arm64/libmonosgen-2.0.so
12-16 22:24:43.924 18210 18210 F DEBUG   :     #12 pc 00000000002afdf4  /data/app/com.companyname.AndroidBindingsJNICrashes-OMT4AzuyDOaf_ESYip9Szg==/lib/arm64/libmonosgen-2.0.so
12-16 22:24:43.924 18210 18210 F DEBUG   :     #13 pc 00000000002b035c  /data/app/com.companyname.AndroidBindingsJNICrashes-OMT4AzuyDOaf_ESYip9Szg==/lib/arm64/libmonosgen-2.0.so
12-16 22:24:43.924 18210 18210 F DEBUG   :     #14 pc 000000000000b7f0  <anonymous:000000744e8c1000>
12-16 22:24:44.237  1077  1077 E /system/bin/tombstoned: Tombstone written to: /data/tombstones/tombstone_07

[jpobst]

Simplified test case
AndroidApp2.zip

[jpobst]

Default and static methods are not supported by Android before API Level 24:
#4574

We thought we had worked around it for .NET 7, but there seems to be a bug preventing it from working like we expected. We will continue to investigate that.

The workaround is to target API-24+ by setting this in your project file:

<SupportedOSPlatformVersion>24</SupportedOSPlatformVersion>

[jonpryor]

On the investigation front, consider AndroidApp2.zip (earlier comment): it has a static method invocation on an interface:

var val = IStaticMethodsInterface.Value;

which results in a crash:

JNI DETECTED ERROR IN APPLICATION: can't call static int com.xamarin.android.StaticMethodsInterface$-CC.getValue() with class java.lang.Class<com.xamarin.android.StaticMethodsInterface>
    in call to CallStaticIntMethodA
    from void crc641149b9fe658fbe8e.MainActivity.n_onCreate(android.os.Bundle)

However, if I manually do what the binding should be doing -- I still need to verify + review that the binding is doing this -- then it works:

static void TryInvokeStaticInterfaceMethod()
{
	Console.WriteLine ("# jonp: trying to get class `com/xamarin/android/StaticMethodsInterface$-CC`…");
	var t = new Java.Interop.JniType ("com/xamarin/android/StaticMethodsInterface$-CC");
	Console.WriteLine ($"# jonp: t={t}");

	Console.WriteLine ("# jonp: trying to get static method `getValue()I`…");
	var m = t.GetStaticMethod ("getValue", "()I");
	Console.WriteLine ($"# jonp: m={m}");

	Console.WriteLine ("# jonp: Invoking static method `getValue()I`…");
	var r = Java.Interop.JniEnvironment.StaticMethods.CallStaticIntMethod (t.PeerReference, m);
	Console.WriteLine ($"# jonp: r={r}");
}

Invoking TryInvokeStaticInterfaceMethod() works as expected, with no crash:

# jonp: trying to get class `com/xamarin/android/StaticMethodsInterface$-CC`…
# jonp: t=JniType(Name='com/xamarin/android/StaticMethodsInterface$-CC' PeerReference=0x1cb6/G)
# jonp: trying to get static method `getValue()I`…
# jonp: m=JniMethodInfo(ID=0x1c3)
# jonp: Invoking static method `getValue()I`…
# jonp: r=3

TODO: figure out why the current binding infrastructure isn't doing what the above manual binding does.

[jonpryor]

@jonpryor wrote:

TODO: figure out why the current binding infrastructure isn't doing what the above manual binding does.

The answer is because we don't pass the jclass corresponding to the type where we found the method; see also:

• https://github.com/xamarin/java.interop/blob/main/src/Java.Interop/Java.Interop/JniPeerMembers.JniStaticMethods.cs#L70-L91
• https://github.com/xamarin/java.interop/blob/main/src/Java.Interop/Java.Interop/JniPeerMembers.JniStaticMethods.cs#L127

What we do is more like:

var from = new Java.Interop.JniType ("com/xamarin/android/StaticMethodsInterface");
var to   = new Java.Interop.JniType ("com/xamarin/android/StaticMethodsInterface$-CC");
var m    = to.GetStaticMethod ("getValue", "()I");

// Note: needs to use `to.PeerReference`, *not* `from.PeerReference`
var r = Java.Interop.JniEnvironment.StaticMethods.CallStaticIntMethod (from.PeerReference, m);