1// Copyright 2011 the V8 project authors. All rights reserved. 2// Redistribution and use in source and binary forms, with or without 3// modification, are permitted provided that the following conditions are 4// met: 5// 6// * Redistributions of source code must retain the above copyright 7// notice, this list of conditions and the following disclaimer. 8// * Redistributions in binary form must reproduce the above 9// copyright notice, this list of conditions and the following 10// disclaimer in the documentation and/or other materials provided 11// with the distribution. 12// * Neither the name of Google Inc. nor the names of its 13// contributors may be used to endorse or promote products derived 14// from this software without specific prior written permission. 15// 16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28// Test that redefining the 'prototype' property of a function object 29// does actually set the internal value and does not screw up any 30// shadowing between said property and the internal value. 31 32var f = function() {}; 33 34// Verify that normal assignment of 'prototype' property works properly 35// and updates the internal value. 36var a = { foo: 'bar' }; 37f.prototype = a; 38assertSame(f.prototype, a); 39assertSame(f.prototype.foo, 'bar'); 40assertSame(new f().foo, 'bar'); 41assertSame(Object.getPrototypeOf(new f()), a); 42assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, a); 43assertTrue(Object.getOwnPropertyDescriptor(f, 'prototype').writable); 44 45// Verify that 'prototype' behaves like a data property when it comes to 46// redefining with Object.defineProperty() and the internal value gets 47// updated. 48var b = { foo: 'baz' }; 49Object.defineProperty(f, 'prototype', { value: b, writable: true }); 50assertSame(f.prototype, b); 51assertSame(f.prototype.foo, 'baz'); 52assertSame(new f().foo, 'baz'); 53assertSame(Object.getPrototypeOf(new f()), b); 54assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, b); 55assertTrue(Object.getOwnPropertyDescriptor(f, 'prototype').writable); 56 57// Verify that the previous redefinition didn't screw up callbacks and 58// the internal value still gets updated. 59var c = { foo: 'other' }; 60f.prototype = c; 61assertSame(f.prototype, c); 62assertSame(f.prototype.foo, 'other'); 63assertSame(new f().foo, 'other'); 64assertSame(Object.getPrototypeOf(new f()), c); 65assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, c); 66assertTrue(Object.getOwnPropertyDescriptor(f, 'prototype').writable); 67 68// Verify that 'prototype' can be redefined to contain a different value 69// and have a different writability attribute at the same time. 70var d = { foo: 'final' }; 71Object.defineProperty(f, 'prototype', { value: d, writable: false }); 72assertSame(f.prototype, d); 73assertSame(f.prototype.foo, 'final'); 74assertSame(new f().foo, 'final'); 75assertSame(Object.getPrototypeOf(new f()), d); 76assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, d); 77assertFalse(Object.getOwnPropertyDescriptor(f, 'prototype').writable); 78 79// Verify that non-writability of redefined 'prototype' is respected. 80assertThrows("'use strict'; f.prototype = {}"); 81assertThrows("Object.defineProperty(f, 'prototype', { value: {} })"); 82 83// Verify that non-configurability of other properties is respected, but 84// non-writability is ignored by Object.defineProperty(). 85// name and length are configurable in ES6 86Object.defineProperty(f, 'name', { value: {} }); 87Object.defineProperty(f, 'length', { value: {} }); 88assertThrows("Object.defineProperty(f, 'caller', { value: {} })"); 89assertThrows("Object.defineProperty(f, 'arguments', { value: {} })"); 90