A Durable Object export may return a Proxy from its constructor to mediate public RPC method access, for example to bind wrapped methods to the original instance. @cloudflare/vitest-pool-workers currently validates and retrieves RPC methods directly from the constructor prototype, then binds the raw method to the returned proxy. This bypasses the proxy's get trap and causes methods using ECMAScript private fields or methods to throw a receiver-brand TypeError.

This changes Durable Object RPC resolution to continue validating prototype visibility first, but then retrieve an allowed method through the constructed instance so proxy wrappers can mediate it. Constructor-assigned own overrides remain rejected, matching native workerd behavior rather than exposing arbitrary instance methods.

The RPC fixture now covers:

• a Durable Object constructor returning a proxy that binds a prototype RPC method which reads a private field; and
• rejection of a constructor-assigned override for an otherwise prototype-visible method.

I additionally checked both behaviors through wrangler dev/native workerd: the proxy-mediated private-field method succeeds, while the constructor-assigned method override is rejected.

• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: this fixes Vitest pool emulation of existing Durable Object RPC behavior and does not introduce a public API or configuration option.

A picture of a cute animal (not mandatory, but encouraged)