Fix package manager registration for CoreCLR

Author: grendello

CLR-Host-Notes.md

@@ -37,3 +37,49 @@ be shared between all targets, which then can (if needed) translate it to the ta
 Runtime currently calls `abort()` in several places.  This should probably become part of the host contract instead.
 Being part of the contract, the target platform could implement process termination on `abort()` in a uniform way
 (includes platform-specific logging, preparation etc)
+
+## Issues and workarounds
+
+### Trimmer issue (as of 14.02.2025)
+
+It appears the trimmer removes a bit too much at this point. In order to make the application run with trimming, one
+needs to add the following to their .csproj (solution found by Ivan Povazan):
+
+```xml
+  <ItemGroup>
+    <TrimmerRootDescriptor Include="MyRoots.xml" />
+  </ItemGroup>
+```
+
+and put the following in the `MyRoots.xml` file:
+
+```xml
+<linker>
+  <assembly fullname="Java.Interop">
+    <type fullname="Java.Interop.JavaArray`1">
+      <method name="get_IsReadOnly" />
+      <method name="System.Collections.ICollection.get_Count" />
+      <method name="System.Collections.ICollection.get_IsSynchronized" />
+      <method name="System.Collections.ICollection.get_SyncRoot" />
+      <method name="System.Collections.ICollection.CopyTo" />
+      <method name="System.Collections.IEnumerable.GetEnumerator" />
+      <method name="System.Collections.IList.get_IsFixedSize" />
+      <method name="System.Collections.IList.get_Item" />
+      <method name="System.Collections.IList.set_Item" />
+      <method name="System.Collections.IList.Add" />
+      <method name="System.Collections.IList.Contains" />
+      <method name="System.Collections.IList.IndexOf" />
+      <method name="System.Collections.IList.Insert" />
+      <method name="System.Collections.IList.Remove" />
+      <method name="System.Collections.IList.RemoveAt" />
+      <method name="System.Collections.Generic.ICollection&lt;T&gt;.Add" />
+      <method name="System.Collections.Generic.ICollection&lt;T&gt;.Remove" />
+      <method name="System.Collections.Generic.IList&lt;T&gt;.Insert" />
+      <method name="System.Collections.Generic.IList&lt;T&gt;.RemoveAt" />
+    </type>
+    <type fullname="Java.Interop.JavaObjectArray`1">
+      <method name="Clear" />
+    </type>
+  </assembly>
+</linker>
+```

src/Mono.Android/Android.Runtime/JNIEnv.cs

@@ -77,6 +77,11 @@ internal static bool ShouldWrapJavaException (Java.Lang.Throwable? t, [CallerMem
 			return wrap;
 		}
 
+		static void MonoDroidUnhandledException (Exception ex)
+		{
+			RuntimeNativeMethods.monodroid_unhandled_exception (ex);
+		}
+
 		internal static void PropagateUncaughtException (IntPtr env, IntPtr javaThreadPtr, IntPtr javaExceptionPtr)
 		{
 			if (!JNIEnvInit.PropagateExceptions)
@@ -95,7 +100,17 @@ internal static void PropagateUncaughtException (IntPtr env, IntPtr javaThreadPt
 				Logger.Log (LogLevel.Info, "MonoDroid", "UNHANDLED EXCEPTION:");
 				Logger.Log (LogLevel.Info, "MonoDroid", javaException.ToString ());
 
-				RuntimeNativeMethods.monodroid_unhandled_exception (innerException ?? javaException);
+				switch (JNIEnvInit.RuntimeType) {
+					case DotNetRuntimeType.MonoVM:
+						MonoDroidUnhandledException (innerException ?? javaException);
+						break;
+					case DotNetRuntimeType.CoreCLR:
+						// TODO: what to do here?
+						break;
+
+					default:
+						throw new NotSupportedException ($"Internal error: runtime type {JNIEnvInit.RuntimeType} not supported");
+				}
 			} catch (Exception e) {
 				Logger.Log (LogLevel.Error, "monodroid", "Exception thrown while raising AppDomain.UnhandledException event: " + e.ToString ());
 			}

src/Xamarin.Android.Build.Tasks/Utilities/ManifestDocument.cs

@@ -673,10 +673,12 @@ XElement CreateApplicationElement (XElement manifest, string applicationClass, L
 
 		IList<string> AddMonoRuntimeProviders (XElement app)
 		{
-			if (AndroidRuntime != AndroidRuntime.MonoVM && AndroidRuntime != AndroidRuntime.CoreCLR) {
-				//TODO: implement provider logic for non-Mono runtimes
-				return [];
-			}
+			(string packageName, string className) = AndroidRuntime switch {
+				AndroidRuntime.MonoVM => ("mono", "MonoRuntimeProvider"),
+				AndroidRuntime.CoreCLR => ("mono", "MonoRuntimeProvider"),
+				AndroidRuntime.NativeAOT => ("net.dot.jni.nativeaot", "NativeAotRuntimeProvider"),
+				_ => throw new NotSupportedException ($"Internal error: unsupported runtime type: {AndroidRuntime}")
+			};
 
 			app.Add (CreateMonoRuntimeProvider ($"{packageName}.{className}", null, --AppInitOrder));
 

src/java-runtime/java/mono/android/MonoPackageManager.java

@@ -27,6 +27,7 @@ public class MonoPackageManager {
 
 	public static void LoadApplication (Context context)
 	{
+		Log.w ("XAMONO", "MonoPackageManager.LoadApplication: start");
 		synchronized (lock) {
 			android.content.pm.ApplicationInfo runtimePackage = context.getApplicationInfo ();
 			String[] apks = null;

src/java-runtime/java/mono/android/clr/MonoPackageManager.java

@@ -18,14 +18,13 @@
 import mono.android.Runtime;
 import mono.android.DebugRuntime;
 import mono.android.BuildConfig;
+import net.dot.android.ApplicationRegistration;
 
 public class MonoPackageManager {
 
 	static Object lock = new Object ();
 	static boolean initialized;
 
-	static android.content.Context Context;
-
 	public static void LoadApplication (Context context)
 	{
 		Log.w ("XACLR", "MonoPackageManager.LoadApplication: start");
@@ -42,7 +41,7 @@ public static void LoadApplication (Context context)
 			}
 
 			if (context instanceof android.app.Application) {
-				Context = context;
+				ApplicationRegistration.Context = context;
 			}
 			if (!initialized) {
 				Log.w ("XACLR", "MonoPackageManager.LoadApplication: initializing");
@@ -89,7 +88,7 @@ public static void LoadApplication (Context context)
 				);
 
 				Log.w ("XACLR", "MonoPackageManager.LoadApplication: call registerApplications");
-				net.dot.android.ApplicationRegistration.registerApplications ();
+				ApplicationRegistration.registerApplications ();
 
 				Log.w ("XACLR", "MonoPackageManager.LoadApplication: initialized");
 				initialized = true;