fix(aot): preserve grain activation constructors

[ReubenBond]

Problem

NativeAOT can remove the public constructor metadata of a concrete grain registered by generated metadata. The grain class resolves successfully, but DefaultGrainActivator cannot find its implicit public parameterless constructor. Manual grain registration needs the same constructor-retention guarantee.

Solution

Preserve public constructors alongside implemented interfaces in TypeManifestOptions.AddInterfaceImplementation, the source-generated registration boundary. Carry the constructor requirement through GrainClassMap and both default activation consumers.

Add GrainTypeOptions.AddClass(Type) as the annotated manual-registration path. Direct access to the legacy Classes collection and construction of a GrainClassMap from an arbitrary dictionary carry trimming warnings requiring separate constructor preservation. Production manifest construction consumes the registered options collection. Collection-boundary suppressions are confined to those established registration contracts.

Constructor selection stays with ActivatorUtilities, including preferred public constructors and activation-scoped dependency identity. Focused tests cover those outcomes in the existing test project and the shared GrainActivation NativeAOT scenario. The expanded native scenario also activates a private grain registered exclusively through AddClass and checks that generated metadata has not registered it. Removing constructor retention at either registration boundary reproduces the corresponding native activation failure; restoring it makes the same scenario pass.

The branch is rebased onto main and reuses the shared smoke harness and common CI from merged #11367. This scenario keeps the wider runtime diagnostic backlog visible while rejecting constructor-path diagnostics; generic grain closure and runtime facet construction retain their existing diagnostics.

The cumulative integration gate verified the original constructor-retention change alongside the existing series in a real Windows x64 NativeAOT executable with dynamic code disabled: ordinary Host.StartAsync, application IAdditionGrain.Add(17, 25) returning 42, and explicit StopAsync with graceful silo shutdown. It kept the original host configuration and deadline, the default-off generated-context setting, and source-generated grain registrations. This proof covers the exercised concrete, non-generic grain and local memory-storage host contract; the expanded focused native scenario verifies the manual-registration correction.

Fixes #11381.

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Copilot review overview

🔵 Needs a closer look

NativeAOT linker behavior and externally owned smoke infrastructure warrant final human validation.

Review effort: Balanced
Findings: None

What changed in this PR

Preserves grain public constructors through generated metadata so default activation works under trimming and NativeAOT.

Changes:

• Propagates constructor-preservation annotations through registration, mapping, and activation.
• Adds managed and NativeAOT activation coverage.
• Documents constructor selection and scoped dependency behavior.

File	Description
test/​Orleans.NativeAotSmoke/​Orleans.NativeAotSmoke.csproj	Configures NativeAOT scenarios.
test/​Orleans.NativeAotSmoke/​NativeAotEnvironment.cs	Validates native execution.
test/​Orleans.NativeAotSmoke/​GrainActivation.smoke.json	Defines diagnostic gates.
test/​Orleans.NativeAotSmoke/​GrainActivation.cs	Exercises native grain activation.
test/​Orleans.Core.Tests/​Runtime/​DefaultGrainActivatorTests.cs	Tests constructor and DI behavior.
src/​Orleans.Serialization/​Configuration/​TypeManifestOptions.cs	Preserves public constructors at registration.
src/​Orleans.Runtime/​README.md	Documents grain construction.
src/​Orleans.Runtime/​Manifest/​GrainClassMap.cs	Propagates constructor metadata guarantees.
src/​Orleans.Runtime/​Facet/​GrainConstructorArgumentFactory.cs	Annotates reflected grain types.
src/​Orleans.Runtime/​Activation/​DefaultGrainActivator.cs	Annotates activation input types.

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[Copilot]

Copilot review overview

🟡 Changes recommended

The trimming suppression is unsound for grain classes registered directly through GrainTypeOptions.Classes.

Review effort: Balanced
Findings: 1

Open (1)

• Unsound IL2067 suppression hides missing constructors for direct registrations · New

[github-actions]

Code coverage

Metric	Pull request
Lines	82.88% (115,456 / 139,303)
Branches	72.18% (33,504 / 46,419)

Report-only conclusion: current-main baseline stale.

The newest successful coverage run tested 171c262, not current main cc1a9ff.

Coverage combines every CI test matrix job, including providers, CodeGen, .NET 8/10, Linux, Windows, and macOS, using canonical physical source and branch identities.

The comparison remains report-only while normal line and branch variance is calibrated.

Coverage details

• Pull request commit: aae978cc0e
• View the pull request test run and coverage artifacts
• View the trusted coverage reporting run

[Copilot]

Copilot review overview

🟢 Approval recommended

Constructor-preservation requirements are consistently propagated and covered by focused managed and NativeAOT tests.

Review effort: Balanced
Findings: None

Resolved since last review (1)

• Unsound IL2067 suppression hides missing constructors for direct registrations