tests/mozilla/js1_5/Scope/scope-001.js

   1 /*
   2 * The contents of this file are subject to the Netscape Public
   3 * License Version 1.1 (the "License"); you may not use this file
   4 * except in compliance with the License. You may obtain a copy of
   5 * the License at http://www.mozilla.org/NPL/
   6 *
   7 * Software distributed under the License is distributed on an "AS
   8 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
   9 * implied. See the License for the specific language governing
  10 * rights and limitations under the License.
  11 *
  12 * The Original Code is mozilla.org code.
  13 *
  14 * The Initial Developer of the Original Code is Netscape
  15 * Communications Corporation.  Portions created by Netscape are
  16 * Copyright (C) 1998 Netscape Communications Corporation. All
  17 * Rights Reserved.
  18 *
  19 * Contributor(s): pschwartau@netscape.com
  20 *
  21 *
  22 * The idea behind bug 53268 is as follows. The item 'five' below is defined
  23 * as const, hence is a read-only property of the global object. So if we set
  24 * obj.__proto__  = this,  'five' should become a read-only propery of obj.
  25 *
  26 * If we then change obj.__proto__  to null, obj.five should initially be
  27 * undefined. We should be able to define obj.five to whatever we want,
  28 * and be able to access this value as obj.five.
  29 *
  30 * Bug 53268 was filed because obj.five could not be set or accessed after
  31 * obj.__proto__  had been set to the global object and then to null.
  32 */
  33 //-----------------------------------------------------------------------------
  34 var bug = '53268';
  35 var status = 'Testing scope after changing obj.__proto__';
  36 var expect= '';
  37 var actual = '';
  38 var obj = {};
  39 const five = 5;
  40
  41
  42 //-----------------------------------------------------------------------------
  43 test();
  44 //-----------------------------------------------------------------------------
  45
  46
  47 function test()
  48 {
  49    enterFunc ("test");
  50    printBugNumber (bug);
  51    printStatus (status);
  52
  53
  54    status= 'Step 1:  setting obj.__proto__ = global object';
  55    obj.__proto__ = this;
  56
  57    actual = obj.five;
  58    expect=5;
  59    reportCompare (expect, actual, status);
  60
  61    obj.five=1;
  62    actual = obj.five;
  63    expect=5;
  64    reportCompare (expect, actual, status);
  65
  66
  67
  68    status= 'Step 2:  setting obj.__proto__ = null';
  69    obj.__proto__ = null;
  70
  71    actual = obj.five;
  72    expect=undefined;
  73    reportCompare (expect, actual, status);
  74
  75    obj.five=2;
  76    actual = obj.five;
  77    expect=2;
  78    reportCompare (expect, actual, status);
  79
  80
  81
  82    status= 'Step 3:  setting obj.__proto__  to global object again';
  83    obj.__proto__ = this;
  84
  85    actual = obj.five;
  86    expect=2;  //<--- (FROM STEP 2 ABOVE)
  87    reportCompare (expect, actual, status);
  88
  89    obj.five=3;
  90    actual = obj.five;
  91    expect=3;
  92    reportCompare (expect, actual, status);
  93
  94
  95
  96    status= 'Step 4:  setting obj.__proto__   to  null again';
  97    obj.__proto__ = null;
  98
  99    actual = obj.five;
 100    expect=3;  //<--- (FROM STEP 3 ABOVE)
 101    reportCompare (expect, actual, status);
 102
 103    obj.five=4;
 104    actual = obj.five;
 105    expect=4;
 106    reportCompare (expect, actual, status);
 107
 108
 109    exitFunc ("test");
 110 }