nucleic-windows/spikes/README.md

M1 spikes (docs/WINDOWS_PORT.md §13)

Programs that answer questions the port is currently guessing at. They are checked in and runnable on purpose: a spike whose answer nobody can reproduce six months later is a rumour.

They are deliberately not in windows/Nucleic.sln. The solution's broker contract tests must keep running on any machine against FakeWslc; these need the Microsoft.WSL.Containers preview NuGet and a real WSL stack, so they are built by path.

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WslcApiDump — what does the wslc API actually look like?

Status: it has served its original purpose (docs/WINDOWS_PORT.md §13.1). The real API is known, and it was obtained without a Windows machine at all — the package is public, so the .nupkg was downloaded, its projection assembly extracted, and its metadata read with MetadataLoadContext. What this tool is for has therefore changed: its assumption list now describes the surface actually observed in 2.9.3, so running it says what the next package version moved, not what we guessed wrong.

Why it is still reflection. Same reason as before: a typed check fails to compile on the first rename and reports one problem, where this reports all of them at once. That property is worth keeping for a preview API whose next version can break anything.

Two facts it discovered that anything referencing this package needs:

• the assembly is wslcsdkcs.dll, not Microsoft.WSL.Containers.dll — loading it by package name fails;
• the only published version is 2.9.3, targeting net8.0-windows10.0.19041.0. The 0.1.0-preview.1 pin this repo carried could never have restored.

cd windows/spikes/WslcApiDump
dotnet run                      # dump the API + check every facade assumption
dotnet run -- --probe           # + call the two read-only statics (service version, missing components)
dotnet run -- --session         # + create a real session and print its live property VALUES

It writes the full public object model to wslc-api-dump.txt (--out to relocate) and prints an ok / MISSING line per assumption, each with why that member matters and a nearest-name hint. It exits 0 even when assumptions fail — a mismatch is the product, not an error. Only a genuinely broken run (the assembly won't load) exits non-zero.

Every path in it has been exercised against a stand-in assembly carrying the observed 2.9.3 type and member names, so a failure on your machine is a finding about wslc, not about this tool.

What to send back: the console output, and wslc-api-dump.txt if anything is MISSING — which now means the package moved under us, not that we guessed wrong.

Why --session earns its risk

--session creates a real wslc session named nucleic-spike under %LOCALAPPDATA%\Nucleic\spike\wslc, starts it, and then creates a second one with the same name. That second construction is the whole point, and it is the last open question D13 turns on: the compat SDK exposes a Session constructor and no attach, so does constructing over an existing name re-adopt it, or refuse?

• Refused (expect WSLC_E_SESSION_RESERVED, 0x80040607) — D13's premise is confirmed on hardware rather than inferred from an IDL, and session reattach genuinely requires IWSLCSessionManager::OpenSessionByName on the internal interface.
• Constructed — the compat surface may re-adopt by name, and the session half of §2.3 reattach may not need the internal interface at all. Check wslc container ps for the first session's containers before believing it.

It leaves the session running on purpose, because that is the other half of the same question: broker supervision assumes wslc state is service-backed, so a crashed nucleic-brokerd can re-adopt rather than orphaning containers. If wslc session ls still shows nucleic-spike after this process exits, that holds. Tear it down with wslc when you're done.

The gateway address is not what this probe is for any more — §13.1 established that no API surfaces one, and D13 moves the control plane to hvsocket via IWSLCVirtualMachine::GetId.

The three answers that change the design

Most mismatches are a one-line edit in WslcFacade.cs — that is exactly what the IWslc seam is for, and nothing above it should move. These three are different:

Finding	Consequence
No container enumeration, stats, pty or attach in the SDK	Settled by D13. wslcsdk.dll wraps WSLCCompat.idl (the stable SDK surface), which genuinely lacks them; they all exist on wslc.idl, the service-internal COM interface wslc.exe calls — ListContainers, Stats, ResizeTty, OpenContainer/Attach, OpenSessionByName, and IWSLCVirtualMachine::GetId. The broker binds both surfaces; no CLI.
No create-or-attach on Session	Answered: IWSLCSessionManager::OpenSessionByName / EnterSession / ListSessions on the internal interface. §2.3 reattach has its mechanism.
No gateway address anywhere on the API	Skip TCP: IWSLCVirtualMachine::GetId returns the VM GUID, so §5's AF_HYPERV/AF_VSOCK path (true vsock parity with macOS) should become primary at M1 (b). Gateway TCP stays as fallback, its address from GetAdaptersAddresses over vEthernet (WSL).
No uid on ProcessSettings	Recoverable, and already planned for: exec wraps argv in setpriv/su agent -c. Interceptors and nash don't care about the numeric uid (§3.2).

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Not yet written

• WslcSpike — the typed happy path: session → GHCR pull of naros-agent → container with an NTFS ContainerVolume → exec git status in the bind-mounted worktree → stdio round-trip → SIGTERM, plus the 9P latency numbers §15 wants (git status and npm install on a real repo, mounted vs. in-VM). Deliberately held back until WslcApiDump has run: written now, against guessed names, it would not compile, and fixing it blind is the mistake this whole approach exists to avoid.
• HvSocketSpike — M1 (b), and now the primary control-plane spike rather than the fallback one (D13): bind an AF_HYPERV listener on the VM GUID from IWSLCVirtualMachine::GetId and dial AF_VSOCK from inside a wslc container. If vsock traverses the container's namespaces, the Windows control plane gets true parity with macOS and §5's firewall/NAT variance stops mattering. Measure gateway-TCP reachability in the same run so the fallback stays evidenced.