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[TrimmableTypeMap] fix JavaPeerableProxy activation gref leak - #11116
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simonrozsival wants to merge 8 commits into
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[TrimmableTypeMap] fix JavaPeerableProxy activation gref leak#11116simonrozsival wants to merge 8 commits into
simonrozsival wants to merge 8 commits into
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Pull request overview
This PR addresses a remaining JNI global reference leak in the NativeAOT / trimmable typemap activation path by ensuring activated peers are constructed (and marked) before invoking inherited activation constructors, and adds regression coverage for both runtime and generator behavior.
Changes:
- Add
JavaPeerProxy.ConstructActivatedPeer()helper for typemap-generated proxy activation. - Update typemap proxy IL emission to pre-construct activated peers before calling inherited activation constructors/UCO constructors.
- Add regression tests: device-side gref leak test during inflation, and generator-side metadata coverage for the new helper reference.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| tests/Mono.Android-Tests/Mono.Android-Tests/Android.Widget/CustomWidgetTests.cs | Adds a device regression test to detect global-ref growth across repeated inflations. |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/TypeMapAssemblyGeneratorTests.cs | Extends generator tests to ensure the new helper is referenced in generated assemblies. |
| src/Mono.Android/Java.Interop/TypeManager.cs | Updates Activate() to construct the peer via ValueManager.ConstructPeer() using the shared uninitialized-object helper. |
| src/Mono.Android/Java.Interop/JavaPeerProxy.cs | Introduces ConstructActivatedPeer() to centralize “pre-construct activated peer” logic for proxies. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/TypeMapAssemblyEmitter.cs | Emits calls to ConstructActivatedPeer() for inherited activation ctor/UCO paths to prevent duplicate gref creation. |
simonrozsival
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dev/peppers/fix-activate-gref-leak
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mainApril 15, 2026 12:32
Fixes: #11101Fixes: #10989 Context: 5c23bcda8 (PR #9640) The Java.Interop Unification (5c23bcd) changed `Object` to extend `JavaObject`, introducing an additional `ConstructPeer` call in the constructor chain. `TypeManager.Activate` was updated to use `SetPeerReference` but never set the `Activatable` state flag. Without it, each `ConstructPeer` call in the constructor chain (`JavaObject()` and `Object.SetHandle()`) creates a new JNI global ref, overwriting the previous one without deleting it — leaking 3 global refs per `LayoutInflater.Inflate` call. Before the fix, the new test fails with: Global reference leak detected: 30 extra global refs after inflating/GC'ing 10 custom views. Before=207, After=237 This went unnoticed because the `Activate` path is only triggered when Java creates .NET objects (not the other way around). The two main scenarios are Activity recreation and custom C# views in Android XML layouts. Most developers use .NET MAUI, which has a single Activity and does not use custom C# views in Android layout XML files, so neither scenario was commonly hit. Changes: - Promote `GetUninitializedObject` from a local function in `CreateProxy` to a shared static method. It sets `Activatable | Replaceable`, which tells `ConstructPeer` to return early and not create duplicate global refs. - Have `Activate` call `GetUninitializedObject` then `ConstructPeer` to create one global ref while `jobject` is still a valid JNI local ref. The `Activatable` flag then prevents duplicates during the constructor chain. - Add regression test that inflates custom views and asserts JNI global reference count does not grow. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…23556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Follow-up to #11112.
This PR keeps the trimmable typemap side of the remaining activation leak fix, scoped to generated proxy activation:
JavaPeerProxy.CreateActivatedPeer(Type, IntPtr)as the shared helper for inherited Java activation pathsTypeinstead of relying on a trim suppressionTypeMapAssemblyGeneratorTestscoverage