Update to mirror JnienvCreateInstance_RegistersMultipleInstances

Context: dotnet/android#10004

It looks like dotnet/android#10004 is closely tied to dotnet/android#9862.

Might as well update tests to hit this behavior!

Author: jonpryor

Diff for: tests/Java.Interop-Tests/Java.Interop/CallVirtualFromConstructorDerived.cs

@@ -1,4 +1,7 @@
-using System;
+#nullable enable
+
+using System;
+using System.Runtime.CompilerServices;
 
 using Java.Interop;
 
@@ -35,10 +38,15 @@ public CallVirtualFromConstructorDerived (int value)
 
 		public  bool    InvokedActivationConstructor;
 
+		public  static  CallVirtualFromConstructorDerived?  Intermediate_FromCalledFromConstructor;
+		public  static  CallVirtualFromConstructorDerived?  Intermediate_FromActivationConstructor;
+
 		public CallVirtualFromConstructorDerived (ref JniObjectReference reference, JniObjectReferenceOptions options)
 			: base (ref reference, options)
 		{
 			InvokedActivationConstructor    = true;
+
+			Intermediate_FromActivationConstructor  = this;
 		}
 
 		public bool Called;
@@ -47,14 +55,16 @@ public override void CalledFromConstructor (int value)
 		{
 			Called      = true;
 			calledValue = value;
+
+			Intermediate_FromCalledFromConstructor  = this;
 		}
 
 		public static unsafe CallVirtualFromConstructorDerived NewInstance (int value)
 		{
 			JniArgumentValue* args = stackalloc JniArgumentValue [1];
 			args [0]    = new JniArgumentValue (value);
 			var o       = _members.StaticMethods.InvokeObjectMethod ("newInstance.(I)Lnet/dot/jni/test/CallVirtualFromConstructorDerived;", args);
-			return JniEnvironment.Runtime.ValueManager.GetValue<CallVirtualFromConstructorDerived> (ref o, JniObjectReferenceOptions.CopyAndDispose);
+			return JniEnvironment.Runtime.ValueManager.GetValue<CallVirtualFromConstructorDerived> (ref o, JniObjectReferenceOptions.CopyAndDispose)!;
 		}
 
 		delegate void CalledFromConstructorMarshalMethod (IntPtr jnienv, IntPtr n_self, int value);
@@ -63,7 +73,7 @@ static void CalledFromConstructorHandler (IntPtr jnienv, IntPtr n_self, int valu
 			var envp = new JniTransition (jnienv);
 			try {
 				var r_self  = new JniObjectReference (n_self);
-				var self    = JniEnvironment.Runtime.ValueManager.GetValue<CallVirtualFromConstructorDerived>(ref r_self, JniObjectReferenceOptions.Copy);
+				var self    = JniEnvironment.Runtime.ValueManager.GetValue<CallVirtualFromConstructorDerived>(ref r_self, JniObjectReferenceOptions.Copy)!;
 				self.CalledFromConstructor (value);
 				self.DisposeUnlessReferenced ();
 			}

Diff for: tests/Java.Interop-Tests/Java.Interop/InvokeVirtualFromConstructorTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.CompilerServices;
 
 using Java.Interop;
 
@@ -7,25 +8,87 @@
 namespace Java.InteropTests {
 
 	[TestFixture]
+#if !__ANDROID__
+	// We want stability around the CallVirtualFromConstructorDerived static fields
+	[NonParallelizable]
+#endif  // !__ANDROID__
 	public class InvokeVirtualFromConstructorTests : JavaVMFixture
 	{
 		[Test]
-		public void InvokeVirtualFromConstructor ()
+		public void CreateManagedInstanceFirst ()
 		{
-			using (var t = new CallVirtualFromConstructorDerived (42)) {
-				Assert.IsTrue (t.Called);
-				Assert.IsNotNull (JniRuntime.CurrentRuntime.ValueManager.PeekValue (t.PeerReference));
-			}
+			CallVirtualFromConstructorDerived.Intermediate_FromActivationConstructor    = null;
+			CallVirtualFromConstructorDerived.Intermediate_FromCalledFromConstructor    = null;
+
+			using var t = new CallVirtualFromConstructorDerived (42);
+			Assert.IsTrue (
+					t.Called,
+					"CalledFromConstructor method override should have been called.");
+			Assert.IsFalse (
+					t.InvokedActivationConstructor,
+					"Activation Constructor should have been called, as calledFromConstructor() is invoked before ManagedPeer.construct().");
+			Assert.IsTrue (
+					t.InvokedConstructor,
+					"(int) constructor should have been called, via ManagedPeer.construct().");
+
+			var registered      = JniRuntime.CurrentRuntime.ValueManager.PeekValue (t.PeerReference);
+			var acIntermediate  = CallVirtualFromConstructorDerived.Intermediate_FromActivationConstructor;
+			var cfIntermediate  = CallVirtualFromConstructorDerived.Intermediate_FromCalledFromConstructor;
+
+			Assert.AreSame (t, registered,
+					"Expected t and registered to be the same instance; " +
+					$"t={RuntimeHelpers.GetHashCode (t).ToString ("x")}, " +
+					$"registered={RuntimeHelpers.GetHashCode (registered).ToString ("x")}");
+			Assert.AreNotSame (t, acIntermediate,
+					"Expected t and registered to be the same instance; " +
+					$"t={RuntimeHelpers.GetHashCode (t).ToString ("x")}, " +
+					$"registered={RuntimeHelpers.GetHashCode (registered).ToString ("x")}");
+			Assert.AreSame (t, cfIntermediate,
+					"Expected t and cfIntermediate to be the same instance; " +
+					$"t={RuntimeHelpers.GetHashCode (t).ToString ("x")}, " +
+					$"cfIntermediate={RuntimeHelpers.GetHashCode (cfIntermediate).ToString ("x")}");
+
+			CallVirtualFromConstructorDerived.Intermediate_FromActivationConstructor    = null;
+			CallVirtualFromConstructorDerived.Intermediate_FromCalledFromConstructor    = null;
 		}
 
 		[Test]
-		public void ActivationConstructor ()
+		public void CreateJavaInstanceFirst ()
 		{
-			var t = CallVirtualFromConstructorDerived.NewInstance (42);
-			using (t) {
-				Assert.IsTrue (t.InvokedActivationConstructor);
-				Assert.IsTrue (t.InvokedConstructor);
-			}
+			CallVirtualFromConstructorDerived.Intermediate_FromActivationConstructor    = null;
+			CallVirtualFromConstructorDerived.Intermediate_FromCalledFromConstructor    = null;
+
+			using var t = CallVirtualFromConstructorDerived.NewInstance (42);
+
+			Assert.IsTrue (
+					t.Called,
+					"CalledFromConstructor method override should have been called.");
+			Assert.IsTrue (
+					t.InvokedActivationConstructor,
+					"Activation Constructor should have been called, as calledFromConstructor() is invoked before ManagedPeer.construct().");
+			Assert.IsTrue (
+					t.InvokedConstructor,
+					"(int) constructor should have been called, via ManagedPeer.construct().");
+
+			var registered      = JniRuntime.CurrentRuntime.ValueManager.PeekValue (t.PeerReference);
+			var acIntermediate  = CallVirtualFromConstructorDerived.Intermediate_FromActivationConstructor;
+			var cfIntermediate  = CallVirtualFromConstructorDerived.Intermediate_FromCalledFromConstructor;
+
+			Assert.AreSame (t, registered,
+					"Expected t and registered to be the same instance; " +
+					$"t={RuntimeHelpers.GetHashCode (t).ToString ("x")}, " +
+					$"registered={RuntimeHelpers.GetHashCode (registered).ToString ("x")}");
+			Assert.AreSame (t, acIntermediate,
+					"Expected t and registered to be the same instance; " +
+					$"t={RuntimeHelpers.GetHashCode (t).ToString ("x")}, " +
+					$"registered={RuntimeHelpers.GetHashCode (registered).ToString ("x")}");
+			Assert.AreSame (t, cfIntermediate,
+					"Expected t and cfIntermediate to be the same instance; " +
+					$"t={RuntimeHelpers.GetHashCode (t).ToString ("x")}, " +
+					$"cfIntermediate={RuntimeHelpers.GetHashCode (cfIntermediate).ToString ("x")}");
+
+			CallVirtualFromConstructorDerived.Intermediate_FromActivationConstructor    = null;
+			CallVirtualFromConstructorDerived.Intermediate_FromCalledFromConstructor    = null;
 		}
 	}
 }