Proxy passed as vm context hides built-in properties.

[psrok1]

• Version: v6.0.0-pre (node-vee-eight-4.9, node-vee-eight-5.0)
• Platform: Linux ubuntu 4.2.0-35-generic Working with nvm, nvmw and similar installation managers #40-Ubuntu SMP Tue Mar 15 22:15:45 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Proxy object is not correctly contextified by vm.createContext routine.

I've tried to create vm with traps on global context, so I made one based on Proxy object.
Unfortunately, code executed inside vm doesn't have any access to built-ins.

> vm.runInNewContext("String", {})
[Function: String]
> vm.runInNewContext("String", new Proxy({},{}))
undefined

Passing required built-ins this way:

ctx = new Proxy({String:String}, {})
vm.runInNewContext("String", ctx)

seems to be (a bit dirty) workaround, but it doesn't resolve a problem at all...

vm.runInNewContext("String.prototype.f = function(){}; ''.f()", ctx)
... because passed String differs from used built-in by string literal, so this code raises an exception (''.f is undefined)

Tested on builds from branches node-vee-eight-4.9/5.0
Proxies doesn't work with older V8s and VMs, because of "not an object" bug.

[Fishrock123]

cc ... @domenic maybe? @ofrobots any idea?

[ofrobots]

I think the issue is because v8::Object::GetRealNamedProperty in node_contextify.cc ends up behaving differently for Proxy objects. I'm not sure this behaviour is intended. I have opened an issue upstream: https://bugs.chromium.org/p/v8/issues/detail?id=4932.

[ofrobots]

This should be fixed upstream in V8 5.2: https://codereview.chromium.org/1929853002. I will request a merge back to V8 5.0 in upstream.