[moetemp]

What changed?

This PR lets a resource declare its type parameters, in Python, TypeScript and .NET. With @nexus.type-parameter "<alias>", the resource class is generic.

• An operation that returns the resource takes a runtime type for each parameter. So the stream sample's Python create_stream(Turn, id=...) returns a Stream[Turn].
• A method takes a runtime type only for a parameter that only its output uses. So the read takes one, and the append takes none. Each language decodes generic response values with the handle's runtime types.
• Go and Java refuse a generic resource. nexgen also refuses one as a record field, or as the result of an operation with no @nexus.proto message, since neither gives the type arguments.

Why?

The proposal's Stream API is generic in its value type, as in Stream[Turn], so a read must decode the body as the handle's type, not as a raw payload. A resource couldn't use a type parameter at all.

How did you test it?

Link to a test plan if any -

• Unit Tests
• Staging
• End to End Tests

The Python, TypeScript and .NET tests read typed values. A parser unit test covers a type parameter alias that use brings in from another interface.

[moetemp]

GitHub marked this as merged after the restack, since its old base came to contain it. It continues upstream as temporalio#358.