Identifying DO namespaces by the existence of idFromName will soon have false positives

[kentonv]

itty-durable currently scans all bindings (the contents of env) to find Durable Object namespace bindings. It decides that a binding is a DO namespace if it has a method idFromName.

itty-durable/src/itty-durable.js

Lines 32 to 36 in 86c8f01

	for (const [key, binding] of Object.entries(env)) {
	this.state[key] = typeof binding.idFromName === 'function'
	? proxyDurable(binding, { name: key, parse: true })
	: binding
	}

In the near future, Workers will introduce a binding type that is a proxy object which appears to have methods of every possible name. Hence, this binding type will incorrectly be detected as a Durable Object namespace.

It appears the effects of this are mostly benign, but it might be worth tightening the test. I think you could perhaps detect these proxy objects by also checking for the presence of an unlikely method name, like __methodThatWillNeverBeDefined or something. If that exists and is a function, you are probably looking at a proxy and not a DO namespace.

[kwhitley]

Awesome catch - I appreciate the heads up!