[native, Mono.Android] Remove WeakReference support #9454
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Context: dotnet/java-interop#1255 Context: xamarin/monodroid@a5c5290 Context: https://issuetracker.google.com/issues/36986478 Context: https://github.com/dotnet/android/blob/b56d68fe2a2c2dffa47eb7e41ae08a00fda86367/Documentation/workflow/SystemProperties.md#debugmonowref Android did not support [JNI Weak Global References][0] until API-8 (Android 2.2). To allow Mono for Android applications to run on API-7 and earlier devices, while using JNI Weak Global References when possible (fewer GC allocations, better performance), the GC bridge supported two modes of operation: * `debug.mono.wref=jni`: Use JNI Weak Global References. * `debug.mono.wref=java`: Use [`java.lang.ref.WeakReference`][1]. With the exception of a ["minor" (lol) issue][2] in KitKat v4.4.2 (API-19) -- in which `JNIEnv::NewGlobalRef()` around a collected JNI Weak Global Reference would return a non-`NULL` value, which would result in app crashes; xamarin/monodroid@a5c52905 added a workaround to use the `WeakReference` backend on Android 4.4.2 -- the `debug.mono.wref=java` backend has not been used since *2014*. Apps *could* use [`@(AndroidEnvironment)`][3] to set `debug.mono.wref=java`, but there is no reason to do so (worse performance!), [nor has anyone done so on GitHub.com][4] (no matches for `debug.mono.wref` within files that would be used with `@(AndroidEnvironment)`). Cleanup src/native and src/Mono.Android, and *remove* support for the `debug.mono.wref=java` backend. [0]: https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#weak_global_references [1]: https://developer.android.com/reference/java/lang/ref/WeakReference [2]: https://issuetracker.google.com/issues/36986478 [3]: https://learn.microsoft.com/dotnet/android/building-apps/build-items#androidenvironment [4]: https://github.com/search?type=code&q=debug.mono.wref
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grendello
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Oct 23, 2024
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Context: dotnet/java-interop#1255
Context: https://github.com/xamarin/monodroid/commit/a5c52905293d7eecdb3c078da62100081b338045
Context: https://issuetracker.google.com/issues/36986478
Context: https://github.com/dotnet/android/blob/b56d68fe2a2c2dffa47eb7e41ae08a00fda86367/Documentation/workflow/SystemProperties.md#debugmonowref
Android did not support JNI Weak Global References until API-8 (Android 2.2). To allow Mono for Android applications to run on API-7 and earlier devices, while using JNI Weak Global References when possible (fewer GC allocations, better performance), the GC bridge supported two modes of operation:
debug.mono.wref=jni: Use JNI Weak Global References.debug.mono.wref=java: Usejava.lang.ref.WeakReference.With the exception of a "minor" (lol) issue in KitKat v4.4.2 (API-19) -- in which
JNIEnv::NewGlobalRef()around a collected JNI Weak Global Reference would return a non-NULLvalue, which would result in app crashes; xamarin/monodroid@a5c52905 added a workaround to use theWeakReferencebackend on Android 4.4.2 -- thedebug.mono.wref=javabackend has not been used since 2014.Apps could use
@(AndroidEnvironment)to setdebug.mono.wref=java, but there is no reason to do so (worse performance!), nor has anyone done so on GitHub.com (no matches fordebug.mono.wrefwithin files that would be used with@(AndroidEnvironment)).Cleanup src/native and src/Mono.Android, and remove support for the
debug.mono.wref=javabackend.