Chakra cannot override RegExp.prototype.exec property

[igor-simoes]

OS: Ubuntu 16.04 x86
Chakra: 1.10.0.0-beta

Step to reproduce:

// RegExp.prototype with overridden exec: Testing ES6 21.2.5.11: 19.b. Let z be ? RegExpExec(splitter, S).
let accesses = [];
let origDescriptor = Object.getOwnPropertyDescriptor(RegExp.prototype, "exec");
let origExec = origDescriptor.value;

Object.defineProperty(RegExp.prototype, "exec", {
    value: function(str) {
        accesses.push("exec");
        return origExec.call(this, str);
    }
});

if (!(accesses == "")) throw new Error("unexpected call to overridden props");
let result = "splitme".split(/it/);
if (!(result == "spl,me")) throw new Error("Unexpec󠁄ted result");
if (!(accesses == "exec,exec,exec,exec,exec,exec")) throw new Error("Property access󠀡es do not match expectation");

Actual results:

Error: Property access󠀡es do not match expectation

Expected results:

Pass without failures

V8, SpiderMonkey and JavascriptCore works as expected.

cinfuzz

[dilijev]

Most likely has to do with this property being configurable: false

[fatcerberus]

RegExp.prototype.exec seems to actually be both configurable and writable so I don't think that's the problem:

#/runtime/assert.mjs:33 module()
(ssj) x Object.getOwnPropertyDescriptor(RegExp.prototype, "exec")
prop  __proto__     {...} *3
prop  value         {...} *4
prop  writable      true
prop  enumerable    false
prop  configurable  true

[fatcerberus]

One thing I don’t understand about the repro above is why there should be six calls to .exec? I’d expect two at most, maybe three if it's divide-and-conquer.

[curtisman]

This test case only make sense when RegEx symbols is enabled, because String.prototype.split is not defined based on Regexp.prototype[@@split].

Currently RegEx symbols is not fully implemented. When I tried with the flag -ES6RegExSymbols, I ran into another exception:
SyntaxError: Syntax error in regular expression
at Global code (blah.js:14:1)

The error comes form the implementation of @@split, where it ask for the flags from the passed in regex and got "undefinedy" which seems wrong to me.

[rhuanjl]

Consolidating as part of #6390