regress-1530.js revision c7cc028aaeedbbfa11c11d0b7b243b3d9e837ed9 
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 x = { foo: 'bar' };
37f.prototype = x;
38assertSame(f.prototype, x);
39assertSame(f.prototype.foo, 'bar');
40assertSame(new f().foo, 'bar');
41assertSame(Object.getPrototypeOf(new f()), x);
42assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, x);
43
44// Verify that 'prototype' behaves like a data property when it comes to
45// redefining with Object.defineProperty() and the internal value gets
46// updated.
47var y = { foo: 'baz' };
48Object.defineProperty(f, 'prototype', { value: y, writable: true });
49assertSame(f.prototype, y);
50assertSame(f.prototype.foo, 'baz');
51assertSame(new f().foo, 'baz');
52assertSame(Object.getPrototypeOf(new f()), y);
53assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, y);
54
55// Verify that the previous redefinition didn't screw up callbacks and
56// the internal value still gets updated.
57var z = { foo: 'other' };
58f.prototype = z;
59assertSame(f.prototype, z);
60assertSame(f.prototype.foo, 'other');
61assertSame(new f().foo, 'other');
62assertSame(Object.getPrototypeOf(new f()), z);
63assertSame(Object.getOwnPropertyDescriptor(f, 'prototype').value, z);
64
65// Verify that non-writability of other properties is respected.
66assertThrows("Object.defineProperty(f, 'name', { value: {} })");
67assertThrows("Object.defineProperty(f, 'length', { value: {} })");
68assertThrows("Object.defineProperty(f, 'caller', { value: {} })");
69assertThrows("Object.defineProperty(f, 'arguments', { value: {} })");
70