fix(nativeaot): generate self-writing RPC responses - #11379

Fixes #11375.

Native RPC response handling selected pooled codecs and copiers by closing open generic implementations at runtime. Generate concrete, non-generic response holders and closed construction graphs for source-known method results and proxy dependencies.

The generator emits identical invocation and registration code for managed and NativeAOT publishing. Closed factories participate through the common provider resolution pipeline, with application registration precedence selecting services in either execution mode. Full emitted-source parity covers result models, collections, primitive responses, completion responses, and explicit serializer contexts.

IInvokable.Invoke(InvocationContext) is the common invocation contract. Runtime clients and observers reuse a context containing their provider-owned serialization services. Generated implementations invoke concrete targets, isolate successful results, and rent concrete holders directly. Completed tasks and value tasks use a synchronous entry; pending results use a concrete asynchronous completion method. Non-generic runtime code supplies compatibility adaptation and envelope release, preserving custom codec/copier selection and same-instance copier results. Response pools share one implementation keyed by the actual envelope type.

Response factory dependencies resolve and undergo compatibility checks during construction. Warmed invocations retain provider-scoped transactional factory resolution, with allocation-free published lookup and reused admission traversal storage.

Exceptions remain original through filters and are copied at delivery. A shared GrainCallInvoker supplies request metadata, filter-stage progression, and response lifetime for incoming and outgoing calls. It retains selected and superseded envelopes through filter continuations, supports restoring earlier selections, and releases owned envelopes exactly once.

Completion takes ownership of its response input. Typed completion extracts the payload and releases the envelope; untyped completion transfers a successful envelope to its consumer. Void consumption and completed outgoing filter chains release their envelopes. Messages release response bodies on successful writes, terminal disposal, and replacement while retaining them during actual retries. Explicit callback handoffs clear the message's ownership before completion.

IRawResponseWriter writes the existing raw protocol directly before the sender queries a response codec. Closed IRawResponseReader registrations reconstruct holders from the wire result type. Direct holders/readers require exact canonical response codec and copier types; custom subclasses preserve their raw wire and copying behavior through compatibility dispatch. Primitive codecs, reference cycles, shared identity, pool reset, completion responses, exceptions, and custom implementation selection retain their established semantics.

Inferred defaults use the existing metadata selector and complete constructor dependency descriptors. Admission validates bound generic constraints before comparing implementation identities, using generated closed argument metadata. Automatic metadata construction retains its ordinary dependency-injection boundary throughout the call chain; inferred default leaves participate in an existing closed transaction or start a transaction as a closed root. Explicit child registrations and selected converter contracts retain precedence throughout canonical codec, copier, and activator aliases.

The combined inferred response graph admits up to 1,024 closed executable types. Aggregate failures report ORLEANS0116 in managed and native builds while retaining holder declarations. Argument failures provide argument-specific guidance, including for one-way contracts. Every response-returning RPC emits the shared non-generic Response graph independently of automatic result admission, allowing explicit-only dictionary and runtime-selected generic result contracts to use runtime response dispatch.

Explicit serializer contexts and inferred RPC response graphs share the graph collector, constructor inspection, provider-owned construction scopes, and metadata registration contracts merged into main. NativeAOT targets .NET 10+, with actual managed .NET 8 compatibility retained. Native coverage uses the shared smoke project and centralized runner.

Draft remains held for fresh CI and final human review.

Microsoft Reviewers: Open in CodeFlow