JSTests/microbenchmarks/string-prototype-split-observable-side-effects.js

//@ runNoFTL

function assert(testedValue, msg) {
    if (!testedValue)
        throw Error(msg);
}

//======================================================================================
// Testing the string that we're calling split on.

// Proxied String subclass.
(function () {
    let accesses = [];
    class ExtString extends String { }
    var obj = new ExtString("splitme");
    var proxy = new Proxy(obj, {
        get(obj, prop) {
            accesses.push(prop.toString());
            if (prop === "toString") {
                return function() {
                    accesses.push("in_toString");
                    return obj.toString();
                }
            }
            return obj[prop];
        }
    });

    assert(accesses == "", "unexpected call to overridden props");
    let result = String.prototype.split.call(proxy, "it");    
    assert(accesses == "Symbol(Symbol.toPrimitive),toString,in_toString", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// Object that looks like a string.
(function () {
    let accesses = [];
    var obj = {
        [Symbol.toPrimitive]() {
            accesses.push(Symbol.toPrimitive.toString());
            return "splitme";
        }
    }

    assert(accesses == "", "unexpected call to overridden props");
    let result = String.prototype.split.call(obj, "it");    
    assert(accesses == "Symbol(Symbol.toPrimitive)", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// Object that looks like a string.
(function () {
    let accesses = [];
    var obj = {
        toString() {
            accesses.push("toString");
            return "splitme";
        }
    }

    assert(accesses == "", "unexpected call to overridden props");
    let result = String.prototype.split.call(obj, "it");    
    assert(accesses == "toString", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// String subclass with overridden @@split.
(function () {
    let accesses = [];
    class ExtString extends String {
        [Symbol.split] (str) {
            accesses.push("Symbol(Symbol.split)");
            return RegExp.prototype[Symbol.split].call(/it/, str);
        }
    };

    var obj = new ExtString;

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);    
    assert(accesses == "Symbol(Symbol.split)", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();


// Object with overridden @@search.
(function () {
    let accesses = [];
    var obj = {
        [Symbol.split] (str) {
            accesses.push("Symbol(Symbol.split)");
            return RegExp.prototype[Symbol.split].call(/it/, str);
        },
    }

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);    
    assert(accesses == "Symbol(Symbol.split)", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

//======================================================================================
// Testing the regexp object that we're calling split with.

// Subclass with overridden [@@species]: Testing ES6 21.2.5.11: 4. Let C be ? SpeciesConstructor(rx, %RegExp%).
(function () {
    let accesses = [];
    class TestRegExp extends RegExp { }
    Object.defineProperty(TestRegExp, Symbol.species, {
        value: function() {
            accesses.push(Symbol.species.toString());
            return /it/y;
        }
    });
    let obj = new TestRegExp;
    let errorStr;

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "Symbol(Symbol.species)", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// RegExp subclass with constructor: Testing ES6 21.2.5.11: 4. Let C be ? SpeciesConstructor(rx, %RegExp%).
(function () {
    let accesses = [];
    class TestRegExp extends RegExp {
        constructor(str, flags) {
            super(str, flags);
            accesses.push("constructor");
        }
    }
    let obj = new TestRegExp("it");

    assert(accesses == "constructor", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "constructor,constructor", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// An object with species constructor: Testing ES6 21.2.5.11: 4. Let C be ? SpeciesConstructor(rx, %RegExp%).
(function () {
    let accesses = [];
    let obj = { constructor: {} };
    obj.constructor[Symbol.species] = function() {
        accesses.push("constructor");
        return /it/y;
    };
    obj[Symbol.split] = function(str, limit) {
        accesses.push(Symbol.split.toString());
        return RegExp.prototype[Symbol.split].call(this, str, limit);
    };

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "Symbol(Symbol.split),constructor", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// RegExp object with overridden flags: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let flags = [ "flags", "global", "ignoreCase", "multiline", "sticky", "unicode" ];
    let flagValues = [ "", false, false, false, false, false ];
    for (let index in flags) {
        (function(flag, flagValue) {
            let accesses = [];
            let obj = /it/;
            Object.defineProperty(obj, flag, {
                get: function() {
                    accesses.push(flag);
                    passed = true;
                    return flagValue;
                }
            });

            assert(accesses == "", "unexpected call to overridden props");
            let result = "splitme".split(obj);
            assert(accesses == flag, "Property accesses do not match expectation");
            assert(result == "spl,me", "Unexpected result");
        }) (flags[index], flagValues[index]);
    }
})();

// RegExp subclass with overridden flags in subclass method: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let flags = [ "flags", "global", "ignoreCase", "multiline", "sticky", "unicode" ];
    let flagValues = [ "", false, false, false, false, false ];
    for (let index in flags) {
        (function(flag, flagValue) {
            let accesses = [];
            class TestRegExp extends RegExp {
                get [flag]() {
                    accesses.push(flag);
                    return flagValue;
                }
            };
            let obj = new TestRegExp(/it/);

            assert(accesses == "", "unexpected call to overridden props");
            let result = "splitme".split(obj);
            assert(accesses == flag, "Property accesses do not match expectation");
            assert(result == "spl,me", "Unexpected result");

        }) (flags[index], flagValues[index]);
    }
})();

// RegExp subclass with overridden flags using Object.defineProperty: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let flags = [ "flags", "global", "ignoreCase", "multiline", "sticky", "unicode" ];
    let flagValues = [ "", false, false, false, false, false ];
    for (let index in flags) {
        (function(flag, flagValue) {
            let accesses = [];
            class TestRegExp extends RegExp { };
            let obj = new TestRegExp(/it/);

            Object.defineProperty(obj, flag, {
                get: function() {
                    accesses.push(flag);
                    return flagValue;
                }
            });

            assert(accesses == "", "unexpected call to overridden props");
            let result = "splitme".split(obj);
            assert(accesses == flag, "Property accesses do not match expectation");
            assert(result == "spl,me", "Unexpected result");

        }) (flags[index], flagValues[index]);
    }
})();

// Any object with species constructor: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let accesses = [];
    let obj = { constructor: {} };
    obj.constructor[Symbol.species] = function() {
        accesses.push("constructor");
        return /it/y;
    };
    obj[Symbol.split] = function(str, limit) {
        accesses.push(Symbol.split.toString());
        return RegExp.prototype[Symbol.split].call(this, str, limit);
    };

    Object.defineProperty(obj, "flags", {
        get: function() {
            accesses.push("flags");
            return "";
        }
    });

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "Symbol(Symbol.split),flags,constructor", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// Any object with custom prototype: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let accesses = [];
    let TestRegExpProto = {
        get flags() {
            accesses.push("flags");
            return "";
        },
        toString() {
            accesses.push("toString");
            return this._regex.toString();
        },
        get source() {
            accesses.push("source");
            return this._regex.source;
        }
    }
    TestRegExpProto.__proto__ = RegExp.prototype;

    let TestRegExp = function(regex) {
        accesses.push("constructor");
        this._regex = new RegExp(regex);
    }
    TestRegExp.prototype = TestRegExpProto;
    TestRegExpProto.constructor = TestRegExp;

    let obj = new TestRegExp(/it/);

    assert(accesses == "constructor", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "constructor,flags,source", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// 2 levels of subclasses: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let accesses = [];

    class RegExpB extends RegExp {
        get flags() {
            accesses.push("flags");
            return "";
        }
    }
    class RegExpC extends RegExpB { }

    assert(RegExpB.__proto__ == RegExp);
    assert(RegExpC.__proto__ == RegExpB);

    let obj = new RegExpC(/it/);

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "flags", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// 2 levels of subclasses with substituted prototype before instantiation: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let accesses = [];

    class B extends RegExp { }
    class C extends B { }

    assert(B.__proto__ === RegExp);
    assert(C.__proto__ === B);
    assert(B.prototype.__proto__ === RegExp.prototype);
    assert(C.prototype.__proto__ === B.prototype);

    let X = function () {}
    Object.defineProperty(X.prototype, "flags", {
        get: function() {
            accesses.push("flags");
            return "";
        }
    });
    Object.defineProperty(X.prototype, "exec", {
        value: function(str) {
            accesses.push("exec");
            var matchResult = /it/y.exec(str.substr(this.lastIndex));
            if (matchResult)
                this.lastIndex += 2; // length of "it".
            return matchResult;
        }
    });

    // Monkey with the prototype chain before instantiating C.
    X.__proto__ = RegExp;
    X.prototype.__proto__ = RegExp.prototype;
    C.__proto__ = X;
    C.prototype.__proto__ = X.prototype;

    assert(X.__proto__ === RegExp);
    assert(C.__proto__ === X);
    assert(X.prototype.__proto__ === RegExp.prototype);
    assert(C.prototype.__proto__ === X.prototype);

    let obj = new C;

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "flags,exec,exec,exec,exec,exec,exec", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// 2 levels of subclasses with substituted prototype after instantiation: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let accesses = [];

    class B extends RegExp { }
    class C extends B { }

    assert(B.__proto__ === RegExp);
    assert(C.__proto__ === B);
    assert(B.prototype.__proto__ === RegExp.prototype);
    assert(C.prototype.__proto__ === B.prototype);

    let X = function () {}
    Object.defineProperty(X.prototype, "flags", {
        get: function() {
            accesses.push("flags");
            return "";
        }
    });
    Object.defineProperty(X.prototype, "exec", {
        value: function(str) {
            accesses.push("exec");
            var matchResult = /it/y.exec(str.substr(this.lastIndex));
            if (matchResult)
                this.lastIndex += 2; // length of "it".
            return matchResult;
        }
    });

    // Instantiate C before monkeying with the prototype chain.
    let obj = new C();

    X.__proto__ = RegExp;
    X.prototype.__proto__ = RegExp.prototype;
    C.__proto__ = X;
    C.prototype.__proto__ = X.prototype;

    assert(X.__proto__ === RegExp);
    assert(C.__proto__ === X);
    assert(X.prototype.__proto__ === RegExp.prototype);
    assert(C.prototype.__proto__ === X.prototype);

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "flags,exec,exec,exec,exec,exec,exec", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// 2 levels of subclasses with proxied prototype: Testing ES6 21.2.5.11: 5. Let flags be ? ToString(? Get(rx, "flags")).
(function () {
    let accesses = [];

    class B extends RegExp { };

    assert(B.__proto__ === RegExp);
    assert(B.prototype.__proto__ === RegExp.prototype);

    let proxy = new Proxy(RegExp.prototype, {
        get: function(obj, prop) {
            accesses.push(prop.toString());
            if (prop === "exec") {
                return function(str) {
                    accesses.push("in_exec");
                    var matchResult = /it/y.exec(str.substr(this.lastIndex));
                    if (matchResult)
                        this.lastIndex += 2; // length of "it".
                    return matchResult;
                }
            }
            return obj[prop];
        }
    });
    B.prototype.__proto__ = proxy;

    let obj = new B();

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "Symbol(Symbol.split),flags,Symbol(Symbol.match),exec,in_exec,exec,in_exec,exec,in_exec,exec,in_exec,exec,in_exec,exec,in_exec", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// RegExp subclass with overridden exec: Testing ES6 21.2.5.11: 19.b. Let z be ? RegExpExec(splitter, S).
(function () {
    let accesses = [];
    class TestRegExp extends RegExp {
        exec(str) {
            accesses.push("exec");
            return RegExp.prototype.exec.call(this, str);
        }
    };
    let obj = new TestRegExp(/it/);

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "exec,exec,exec,exec,exec,exec", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();

// Proxied RegExp observing every get.
(function () {
    let accesses = [];
    let regexp = new RegExp(/it/);
    let proxy = new Proxy(regexp, {
        get(obj, prop) {
            accesses.push(prop.toString());
            return obj[prop];
        }
    });

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(proxy);
    // Note: @@split creates a new instance of the RegExp using its @@species, and performs
    // the split operation with that new instance. Hence, the proxy is only able to observe
    // gets up to the creation of the new instance.
    assert(accesses == "Symbol(Symbol.split),constructor,flags,Symbol(Symbol.match),source",
        "Proxy not able to observe some gets");
    assert(result == "spl,me", "Unexpected result");
})();

// Proxied RegExp (without @@match) observing every get.
// This is to force the RegExp @species constructor to access source.
(function () {
    let accesses = [];
    let regexp = new RegExp(/it/);
    let proxy = new Proxy(regexp, {
        get(obj, prop) {
            accesses.push(prop.toString());
            if (prop == Symbol.match)
                return undefined;
            return obj[prop];
        }
    });

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(proxy);
    // Note: @@split creates a new instance of the RegExp using its @@species, and performs
    // the split operation with that new instance. Hence, the proxy is only able to observe
    // gets up to the creation of the new instance.
    assert(accesses == "Symbol(Symbol.split),constructor,flags,Symbol(Symbol.match),Symbol(Symbol.toPrimitive),toString,source,flags",
        "Proxy not able to observe some gets");
    // The new instance of the RegExp would have been constructed with the pattern from
    // the proxy toString() i.e. "\/lt\/" instead of source, because the proxy is an
    // object without a [@@match] property.
    assert(result == "splitme", "Unexpected result");
})();