F# code generation Phase C (partial): static-response HTTP endpoints (GH-2969)

[jeremydmiller]

Phase C of the F# code-generation audit (#2969) — Wolverine.Http. Stands up the HTTP F# fixture surface and renders a real HttpChain to compilable F# for the static-response (GET) path.

Stacked on the feat-2969-fsharp-codegen-foundation branch (with A+B). Note: Phase B still needs to reach main via #2974 — watch merge order (phase→foundation before foundation→main).

What's here

• New per-surface trio under src/Testing/: Wolverine.Http.FSharpContracts (endpoint classes), Wolverine.Http.FSharpFixture (F#, checked-in Generated.fs), Wolverine.Http.FSharpTests (compile gate + HTTP fsharp-coverage smoke test). Added to wolverine_fsharp.slnx; CI now runs dotnet test wolverine_fsharp.slnx across both the Core and Http surfaces.
• No-web-host rendering: HttpChain.ChainFor<T>(x => x.Method(), httpGraph) → httpGraph.StartAssembly(rules) → AssembleTypes → GenerateFSharpCode(new ServiceCollectionServerVariableSource(container)). The generated type subclasses the public HttpHandler base (override _.Handle(httpContext) : Task).
• WriteStringFrame emits F# — HttpHandler.WriteString is static, so it resolves without a this. A [WolverineGet] string endpoint renders and compiles end to end.

Generated F#

type GET_fsharp_hello(wolverineHttpOptions: WolverineHttpOptions) =
    inherit Wolverine.Http.HttpHandler(wolverineHttpOptions)
    override _.Handle(httpContext: HttpContext) : Task =
        task {
            let thingEndpoints = ThingEndpoints()
            let result_of_Hello = thingEndpoints.Hello()
            do! Wolverine.Http.HttpHandler.WriteString(httpContext, result_of_Hello)
        }

Deferred — blocked on a JasperFx-layer gap (to be filed upstream)

HttpHandler.ReadJsonAsync<T> and WriteJsonAsync<T> are instance methods called unqualified in the generated handler. F# can't resolve them from a member _.Handle body (no self identifier), so ReadJsonBody / WriteJsonFrame — the whole JSON POST path — can't emit F# until JasperFx emits a named self for generated members (e.g. member this.Handle + frames emit this.WriteJsonAsync). This is the same root gap as RecordMessageCausationFrame (Phase B) and is the single biggest lever for HTTP coverage. The POST endpoint is kept in the contracts for that follow-up but isn't rendered yet.

Verification

• Compile-gate — the regenerated Generated.fs (GET endpoint) compiles via dotnet build.
• fsharp-coverage with Wolverine.Http loaded — 25 implemented / 2 skipped / 54 remaining of 81.
• dotnet build wolverine_fsharp.slnx -c Release + all 4 gate/coverage tests — green.
• Full dotnet build wolverine.slnx -c Release regression — 0 warnings, 0 errors.

Part of #2969.

🤖 Generated with Claude Code