Illegal invocation error using ES6 Proxy and node.js

Hello,
I am unable to call a node.js native function through a No-op forwarding proxy.

The following case works properly with a v8 native function:

var p = new Proxy(Math, {});
console.log( p.cos.toString() ); // function cos() { [native code] }
console.log( p.cos(0) ); // 1

Whereas the following case throw TypeError: Illegal invocation

var p = new Proxy(require('os'), {});
console.log( p.cpus.toString() ); // function getCPUs() { [native code] }
console.log( p.cpus() ); // TypeError: Illegal invocation

what's wrong ?

Maybe it is because the Math methods are static, while the Node.js modules' methods could require an appropriate receiver. This works:

const os = require('os');
const p = new Proxy(os, {});
console.log(p.cpus);
console.log(p.cpus.call(os));

See also: Exploring ES6 by Dr. Axel Rauschmayer: 28. Metaprogramming with proxies: 28.3.2 Intercepting method calls

receiver for the default get proxy handler is handled with Reflect.get(target, property, receiver)

This case is also weird (note that I use node.js v7.7.1):

const p = new Proxy(require('os'), {});

var cpus = p.cpus;
console.log(cpus()); // ok

console.log(p.cpus()); // Illegal invocation

@FranckFreiburger

@FranckFreiburger
Maybe this is somehow connected with C++ bindings, This works:

var p = new Proxy(require('os'), {});
console.log(p.arch.toString());
console.log(p.arch());

os.arch() does not use bindings. os.cpus() does use them.

This issue isn't reproducible on master or v7.x-staging, probably as a side effect of #11564. Either way, the next release of v7.x will have this fixed.

cpus is only one function affected by this bug. Other methods that directly call C++ bindings are also vulnerable. On the V8 level, it is probably because the API call helper cannot find a compatible receiver in a Proxy object.

This bug has already been reported upstream by as issue 5773.

/cc @nodejs/v8

Note that all binding.* functions seems to be affected by this bug.

new Proxy(require('os'), {}).hostname() // Illegal invocation ...

Is there anything Node.js can/should do about this other than await https://bugs.chromium.org/p/v8/issues/detail?id=5773 getting fixed in V8? Should this issue remain open?

This is still an issue but AFAICT there is nothing Node.js can do about it.

Repro on v8.x:

const binding = process.binding('util');
const isDate = binding.isDate;
console.log(isDate(new Date)); // true
console.log(isDate.call(binding, new Date)); // true
console.log(isDate.call(new Proxy(binding, {}), new Date)); // illegal invocation

This is still an issue as of Node v9.8.0. Can/should anyone push for a v8 fix, or should there be any sort of Node workaround? Or are users expected to rebind to the unproxied contexts for all of these calls?

BTW, this comes up in surprisingly common places, e.g. trying to stringify a Proxied Buffer.

let buf = new Proxy(Buffer.from('test'), { get: (t, n) => t[n] })
console.log(buf)

fwiw this is intended behavior on the side of proxies. check out https://github.com/nodejs/node/pull/18131/files#diff-cc63475f116262e9cbea02374e344c01R671 for an example of a proxy that covers this use case.

Even if this is fully compliant with the spec, it's quite a pain. As Proxies become a more widely adopted feature I expect many more people will run into this. At the very least, there should be a workaround on the Node side.

@mappum

@mappum that's the general idea of the membrane concept: https://www.npmjs.com/package/es7-membrane

The examples listed in this issue work with master so I think this can be closed out.

As to this example (edited for brevity):

new Proxy(Buffer.from('test'), { get: (t, n) => t[n] }).toString()

That invokes Buffer.prototype.toString() with the proxy as the receiver and fails the way it is expected to.

Talk of "there should be a workaround on the Node side" is misguided because it's not a sensible construct. Write it like this and note the .bind() call:

new Proxy(Buffer.from('test'), { get: (t, n) => t[n].bind(t) }).toString()

- https://bugs.chromium.org/p/v8/issues/detail?id=5773 and nodejs/nod…

On chrome I have same problem for events (eg. click event) - here is solution

const eventProxy = new Proxy(event, {
    get: (target, prop) => ()=> target[prop].apply(target),
});

working editable example here which shows how to add your code before/after original function execution

Navigation Menu

Repository navigation

Illegal invocation error using ES6 Proxy and node.js #11629

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Illegal invocation error using ES6 Proxy and node.js #11629

Description

Activity

vsemozhetbyt commented on Mar 1, 2017

vsemozhetbyt commented on Mar 1, 2017

FranckFreiburger commented on Mar 5, 2017

FranckFreiburger commented on Mar 5, 2017

vsemozhetbyt commented on Mar 5, 2017

TimothyGu commented on Mar 6, 2017

TimothyGu commented on Mar 6, 2017

FranckFreiburger commented on Mar 6, 2017

Trott commented on Jul 30, 2017

targos commented on Aug 3, 2017

mappum commented on Mar 11, 2018

mappum commented on Mar 12, 2018

devsnek commented on Mar 12, 2018

mappum commented on Mar 12, 2018

devsnek commented on Mar 12, 2018

bnoordhuis commented on Mar 13, 2018

kamil-kielczewski commented on May 31, 2023

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions