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[Mono.Android] fix global ref leak in TypeManager.Activate #11112

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[Mono.Android] fix global ref leak in TypeManager.Activate #11112

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31a44fa
Bump to dotnet/java-interop/dev/peppers/gref-leak; add regression test
jonathanpeppers Apr 15, 2026
7c591e2
Improve test: use two rounds to avoid background thread noise
jonathanpeppers Apr 15, 2026
6c261df
Fix flaky test: inflate 100 times with generous threshold
jonathanpeppers Apr 15, 2026
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2 changes: 1 addition & 1 deletion external/Java.Interop
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Submodule Java.Interop updated 3 files
+2 −0 src/Java.Interop/Java.Interop/JniObjectReference.cs
+3 −2 src/Java.Interop/Java.Interop/JniRuntime.JniValueManager.cs
+38 −0 tests/Java.Interop-Tests/Java.Interop/JniRuntimeJniValueManagerContract.cs
44 changes: 43 additions & 1 deletion tests/Mono.Android-Tests/Mono.Android-Tests/Android.Widget/CustomWidgetTests.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using Android.App;
using System;
using Android.App;
using Android.Content;
using Android.Util;
using Android.Views;
Expand Down Expand Up @@ -44,6 +45,47 @@ public void UpperAndLowerCaseCustomWidget_FromLibrary_ShouldNotThrowInflateExcep
inflater.Inflate (Resource.Layout.upper_lower_custom, null);
}, "Regression test for widgets with uppercase and lowercase namespace (bug #23880) failed.");
}

// https://github.com/dotnet/android/issues/11101
[Test]
public void InflateCustomView_ShouldNotLeakGlobalRefs ()
{
var inflater = (LayoutInflater) Application.Context.GetSystemService (Context.LayoutInflaterService);
Assert.IsNotNull (inflater);

// Warm up: inflate once to populate caches and type mappings,
// and let any background thread activity from previous tests settle.
inflater.Inflate (Resource.Layout.lowercase_custom, null);
CollectGarbage (times: 3);

int grefBefore = Java.Interop.Runtime.GlobalReferenceCount;

// Use a large number of inflations so that a real leak (3+ global refs
// per inflate) produces a delta far above any background noise from
// Android system services, GC bridge processing, or finalizer threads.
const int inflateCount = 100;
for (int i = 0; i < inflateCount; i++) {
inflater.Inflate (Resource.Layout.lowercase_custom, null);
}

CollectGarbage (times: 3);

int grefAfter = Java.Interop.Runtime.GlobalReferenceCount;
int delta = grefAfter - grefBefore;

// A real leak would produce delta >= 300 (3 leaked refs per inflate).
// Use a generous threshold to tolerate background noise on real devices.
Assert.IsTrue (delta <= 100,
$"Global reference leak detected: {delta} extra global refs after inflating/GC'ing {inflateCount} custom views. Before={grefBefore}, After={grefAfter}");

static void CollectGarbage (int times)
{
for (int i = 0; i < times; i++) {
GC.Collect ();
GC.WaitForPendingFinalizers ();
}
}
}
}

public class CustomButton : Button
Expand Down