Memory Leak: MainActivity instances are not garbage-collected after destroy

[markusroessler]

Description

MainActivity instances (and everything referenced from them) never get garbage-collected with MAUI 10.0.51.
Last working version: 9.0.120.

Please have a look at: https://github.com/markusroessler/MauiActivityMemoryleak
This sample app does the following:

• Starts an Android Foreground Service (see MainApplication.OnCreate) - this prevents the Application from terminating when the last Activity closes
• Periodically invokes the garbage collector (see GCHelper)
• Monitors the MainActivity instance count (see GCHelper)

Steps to Reproduce

• Start the sample app: https://github.com/markusroessler/MauiActivityMemoryleak
• Close and reopen the MainActivity several times (via app drawer)
• Wait for the some GC runs (see console output MauiActivityMemoryleak.GCHelper: Information: GC.Collect)

in the console you will see something like:

MauiActivityMemoryleak.GCHelper: Information: Instance count (MauiActivityMemoryleak.MainActivity): 3

A .NET heap dump showed that there are actually no live MainActivity instances. But in the Java heap dump there are still 3 active instance all referenced by JNI GlobalRefs:

Link to public reproduction project repository

https://github.com/markusroessler/MauiActivityMemoryleak

Version with bug

10.0.50

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

9.0.120 SR12

Affected platforms

Android

Affected platform versions

Android 16

Did you find any workaround?

no, even an explicit MainActivity.Dispose() doesn't help.

Relevant log output

[dartasen]

Might be related to dotnet/android#10989

[HarishKumarSF4517]

This issue has been validated in Visual Studio Code 1.115.0 with .NET MAUI versions 9.0.120, 10.0.0-preview1 and 10.0.51. It can be reproducible from 10.0.0-preview1 on the Android Platform. I have attached the snap for reference:

9.0.120	10.0.0-preview1