src/v8/test/mjsunit/for-in-special-cases.js

// Copyright 2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
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//       with the distribution.
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//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// Flags: --expose-gc

function for_in_null() {
  try {
    for (var x in null) {
      return false;
    }
  } catch(e) {
    return false;
  }
  return true;
}

function for_in_undefined() {
  try {
    for (var x in undefined) {
      return false;
    }
  } catch(e) {
    return false;
  }
  return true;
}

for (var i = 0; i < 10; ++i) {
  assertTrue(for_in_null());
  gc();
}

for (var j = 0; j < 10; ++j) {
  assertTrue(for_in_undefined());
  gc();
}

assertEquals(10, i);
assertEquals(10, j);


function Accumulate(x) {
  var accumulator = [];
  for (var i in x) {
    accumulator.push(i);
  }
  return accumulator;
}

for (var i = 0; i < 3; ++i) {
  assertEquals(Accumulate("abcd"), ['0', '1', '2', '3']);
}

function for_in_string_prototype() {

  var x = new String("abc");
  x.foo = 19;
  function B() {
    this.bar = 5;
    this[7] = 4;
  }
  B.prototype = x;

  var y = new B();
  y.gub = 13;

  var elements = Accumulate(y);
  var elements1 = Accumulate(y);
  // If for-in returns elements in a different order on multiple calls, this
  // assert will fail.  If that happens, consider if that behavior is OK.
  assertEquals(elements, elements1, "For-in elements not the same both times.");
  assertEquals(["7","bar","gub","0","1","2","foo"], elements)

  assertEquals(['0', '1', '2', 'foo'], Accumulate(x))
}

for_in_string_prototype();
for_in_string_prototype();


(function for_in_dictionary_prototype_1() {
  let prototype1 = {prop: 0, prop1: 1};
  let derived1 = Object.create(null, {
    prop: {enumerable: false, configurable: true, value: 0},
  });
  Object.setPrototypeOf(derived1, prototype1);

  let prototype2 = {prop: 0, prop1: 1};
  let derived2 = Object.create(prototype2, {
    prop: {enumerable: false, configurable: true, value: 0},
  });

  for (let i = 0; i < 3; i++) {
    assertEquals(['prop1'], Accumulate(derived1));
    assertEquals(['prop1'], Accumulate(derived2));
  }
})();

(function for_in_dictionary_prototype_2() {
  let prototype1 = {prop: 0, prop1: 1};
  let derived1 = Object.create(null, {
    prop: {enumerable: false, configurable: true, value: 1},
    prop2: {enumerable: true, configurable: true, value: 2},
    prop3: {enumerable: false, configurable: true, value: 3},
  });
  Object.setPrototypeOf(derived1, prototype1);

  let prototype2 = {prop: 0, prop1: 1};
  let derived2 = Object.create(prototype2, {
    prop: {enumerable: false, configurable: true, value: 0},
    prop2: {enumerable: true, configurable: true, value: 2},
    prop3: {enumerable: false, configurable: true, value: 3},
  });

  for (let i = 0; i < 3; i++) {
    assertEquals(['prop2', 'prop1'], Accumulate(derived1));
    assertEquals(['prop2', 'prop1'], Accumulate(derived2));
  }
})();