🐛 Bug: WorkerEntrypoint wrapped with Proxy throws error when invoked

[rtbenfield]

A WorkerEntrypoint class implementation that is wrapped in a Proxy throws the following runtime error when the service binding is invoked. This was created in a Worker with a service binding to its own entrypoint for testing.

✘ [ERROR] workerd/io/worker.c++:1819: error: worker is not an actor but class name was requested; n = RpcEntrypoint

class RpcEntrypointImpl extends WorkerEntrypoint {
	myRpcCall() {
		return { ok: true }
	}
}
export const RpcEntrypoint = new Proxy(RpcEntrypointImpl, {})

// logs RpcEntrypoint__proto__ [Function: WorkerEntrypoint]
console.log('RpcEntrypoint__proto__', RpcEntrypoint.__proto__)

I found the error at the line below and attempted to trace how WorkerEntrypoint exports are determined. From what I understand, it should be detecting from __proto__, though in the JS side this seems to be retained by the proxy wrapper. This is my first time digging through the workerd code though so I could be off track.

workerd/src/workerd/io/worker.c++

Line 1819 in 92c30c9

LOG_ERROR_PERIODICALLY("worker is not an actor but class name was requested", n);

Why proxy a WorkerEntrypoint?

I'm attempting the Proxy wrapper as a way to apply OpenTelemetry instrumentation to a WorkerEntrypoint class. The proxy would extract the env form the constructor for configuration, wrap all RPC method invocations in spans, and export those spans automatically when the RPC method completes.