EW-10529 Route OutgoingFactory subrequests through getSubrequestNoChecks

[harrishancock]

TcpPortOutgoingFactory (containers) and StreamOutgoingFactory (TCP sockets) constructed WorkerInterface instances directly, bypassing getSubrequestNoChecks() and missing the external memory adjustment that pressures V8's GC. Route them through getSubrequestNoChecks() so they get the same accounting as other subrequest types.

Also add comments on OutgoingFactory, CrossContextOutgoingFactory, getSubrequestNoChecks(), getCapnpChannel(), and getClientWithTracing() documenting the contract: implementations that create HTTP connections should route through getSubrequestNoChecks() internally.

Assisted-by: Claude

[github-actions]

The generated output of @cloudflare/workers-types matches the snapshot in types/generated-snapshot 🎉

[ask-bonk]

I now have a complete understanding of the change. Let me summarize my analysis:

What the PR does:

1. Routes TcpPortOutgoingFactory::newSingleUseClient() (containers) and StreamOutgoingFactory::newSingleUseClient() (TCP sockets) through getSubrequestNoChecks() to get the external memory adjustment (8KB pressure on V8 GC).
2. Adds documentation comments on OutgoingFactory, CrossContextOutgoingFactory, getSubrequestNoChecks(), and getCapnpChannel() explaining the contract.

Analysis:

The change is well-structured. The two factories that were previously constructing WorkerInterface instances directly now route through getSubrequestNoChecks(), which provides:

• External memory adjustment (8KB) to pressure V8's GC
• Tracing support (though neither caller passes operationName)
• Optional metrics wrapping (both pass wrapMetrics = false)

Both use {.inHouse = false, .wrapMetrics = false} which is reasonable — containers and TCP sockets are external and don't need metrics wrapping at this level.

The callback parameters (tracing, channelFactory) are unused in both cases since these factories don't need tracing or channel factory access — they construct their own WorkerInterface directly. This is fine; the important part is the wrapping that getSubrequestNoChecks applies after the callback returns.

The actor factories (GlobalActorOutgoingFactory, LocalActorOutgoingFactory, ReplicaActorOutgoingFactory, FacetOutgoingFactory) already route through getSubrequest() which calls getSubrequestNoChecks() internally — so they're already covered.

The documentation comments are accurate and helpful, clearly stating the contract.

I don't see any actionable issues — the change is correct, well-scoped, and the documentation additions are valuable.

LGTM

github run

[jasnell]

PR will need to be rebased on main for CI to run successfully.

[harrishancock]

Rebased on main.